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Welcome to Microbiology at Delta College!

Bio 203, General Microbiology & Infection Control

Joyce Howard, Delta College

Bio 203, General Microbiology & Infection Control
Bio 203 Exam Two Lecture Notes

These lecture notes are a compilation of the information you are learning through your assignments. Some of the information has been organized to assist you with preparation and study for Exam Two. The rest of the information will be yours to organize from the assignments.

From assignment, Isolation Precautions & Hand Hygiene:

Isolation Precautions:

The link to the Isolation Precautions Guideline: http://www.cdc.gov/ncidod/hip/isolat/isolat.htm
In the health care field, we refer to measures employed to protect yourself and your patients as isolation precautions. Since the need for such precautions was first recognized in 1877, a series of precaution guidelines have evolved.
To assist hospitals in maintaining up-to-date isolation practices, the Centers for Disease Control and Prevention (CDC) and the Hospital Infection Control Practices Advisory Committee (1) (HICPAC) have revised the "CDC Guideline for Isolation Precautions in Hospitals."
HICPAC was established in 1991 to provide advice and guidance to the Secretary, Department of Health and Human Services (DHHS); the Assistant Secretary for Health, DHHS; the Director, CDC; and the Director, National Center for Infectious Diseases, regarding the practice of hospital infection control and strategies for surveillance, prevention, and control of nosocomial infections in US hospitals. HICPAC also advises the CDC on periodic updating of guidelines and other policy statements regarding prevention of nosocomial infections.

Universal Precautions (UP):

In 1985, largely because of the HIV epidemic, Universal Precautions (UP) were developed for all health care workers. These guidelines emphasized applying blood and body fluid precautions universally to all persons regardless of their infection status. UP were updated in 1987 and 1988.

Universal Precautions included:
All health care workers should use barrier precautions to prevent skin and mucous membrane exposure when contact is anticipated with blood, semen, vaginal secretions, cerebrospinal fluid, synovial fluid, pleural fluid, peritoneal fluid, pericardial fluid, amniotic fluid, or any body fluid containing visible blood.
Barrier protection should also be used for handling items and/or surfaces soiled with blood or body fulids.
Gloves should be worn for venipuncture and for touching blood and body fluids, mucous membranes, or nonintact skin.
Masks, owns, and protective eyewear should be worn for procedures likkely to generate droplets, splashes, or sparys of blood or body fluids.
Gloves should be changed after contact with each patient. Gloves should not be washed or reused. Hands should be washed immediately after gloves are removed.
Precautions should be used to prevent injuries when using , cleaning, or disposing of needles, scalpels, and other sharp instruments or devices. These should be placed in puncture-resistant contianers for disposal.
Resuscitation bags should be available to avoid mouth-to-mouth contact.
Health care workers with open lesions should not be involved in direct patient care or handling patient-care equipment.

Body Substance Isolation (BSI):

In 1987, Body Substance Isolation (BSI) guidelines were proposed.
BSI emphasized isolation of all moist and potentially infectious body substances from all patients, primarily through the use of gloves.
In BSI, signs are placed on the doors of patients with airborne infections, referring visitors to the floor nurse before entering.
BSI stressed the application of fresh gloves before contact with moist body substances.
It did not emphasize hand washing after removal of gloves, unless the hands were visibly soiled because of glove punctures.

OSHA Bloodborne Pathogens Standard:

In 1991, OSHA’s final rule of the Bloodborne Pathogens Standard was published. It emphasized universal precautions.

Standard and Transmission-Based Precautions:

By the 1990s many healthcare workers were uncertain about which guidelines to follow!
Besides Universal Precautions, other guidelines for infection control being practiced included Body Substance Isolation, Blood and Body Fluid Precautions, Category-Specific Isolation, and Disease-Specific Isolation. Most health care settings were using a mixed combination of all the guidelines, referring to them as universal precautions.
As a result, the Standard and Transmission-Based Precautions were agreed upon by the CDC, HICPAC, Public Health Service, and U.S. Department of Health and Human Services.
These came out in draft form in 1994 and final form in 1996.

Five Routes of Transmission:

There are five main routes of transmission: contact, droplet, airborne, common vehicle, and vectorborne.
Contact transmission is the most important and frequent mode of transmission of nosocomial infections. It is divided into two subgroups:

Direct-contact transmission involves a direct body surface to body surface contact and physical transfer of microorganisms between a susceptible host and an infected or colonized person, such as occurs when a person turns a patient, gives a patient a bath, or performs other patient-care activities that require direct personal contact.

Direct-contact transmission also can occur between two patients, with one serving as the source of the infectious microorganisms and the other as a susceptible host.

Indirect-contact transmission involves contact of a susceptible host with a contaminated intermediate object, usually inanimate, such as contaminated instruments, needles, or dressings, or contaminated hands that are not washed and gloves that are not changed between patients.
Droplet transmission involves the formation of droplets, which are generated from the source person primarily during coughing, sneezing, and talking, and during the performance of certain procedures such as suctioning and bronchoscopy.

Transmission occurs when droplets containing microorganisms generated from the infected person are propelled a short distance through the air and deposited on the host's conjunctivae, nasal mucosa, or mouth.
Because droplets do not remain suspended in the air, special air handling and ventilation are not required to prevent droplet transmission; that is, droplet transmission must not be confused with airborne transmission.

Airborne transmission occurs by dissemination of either airborne droplet nuclei (small-particle residue, 5 µm or smaller in size, of evaporated droplets containing microorganisms that remain suspended in the air for long periods of time) or dust particles containing the infectious agent.

Microorganisms carried in this manner can be dispersed widely by air currents and may become inhaled by a susceptible host within the same room or over a longer distance from the source patient, depending on environmental factors.
Special air handling and ventilation are required to prevent airborne transmission.
Microorganisms transmitted by airborne transmission include Mycobacterium tuberculosis, the Rubeola virus, and the Varicella virus.

Common vehicle transmission applies to microorganisms transmitted by contaminated items such as food, water, medications, devices, and equipment.
Vectorborne transmission occurs when vectors such as mosquitoes, flies, rats, and other vermin transmit microorganisms.

This route of transmission is of less significance in hospitals in the United States than in other regions of the world.

Standard Precautions:

You are to apply Standard Precautions as a healthcare worker:

Each and every time you work with a patient.
Apply to blood.
Apply to all body fluids, secretions, and excretions except sweat, regardless of whether or not they contain visible blood. Body fluids include urine, feces, pus, saliva, spit, tears, mucus, vomit, sputum, vaginal or penal secretions, afterbirth and any other fluid-like substance which could come from a patient.
Apply to nonintact skin.
Apply to mucous membranes.
Standard Precautions are designed to reduce the risk of transmission of microorganisms from both recognized and unrecognized sources of infection and are meant to bring about the control of infections.
An obvious time you will be exposed directly to bodily fluids is during specimen collection. Therefore, as you learn to collect specimens in the lab you will learn how to employ isolation precautions.

Standard Precautions Include:

Handwashing:

Handwashing is the single most important measure to reduce the risks of transmitting organisms from one person to another or from one site to another on the same patient.
Wash hands after touching blood, body fluids, secretions, excretions, and contaminated items, regardless of whether gloves were worn.
Wash hands (1) immediately after removing gloves, (2) between patient contacts (i.e., as you move from one patient to your next patient), and (3) whenever it would be wise and prudent.
Wash hands between tasks and procedures on the same patient to prevent cross contamination of different body sites.
Use a plain (nonantimicrobial) soap for routine handwashing.
Use an antimicrobial agent or a waterless antiseptic agent for specific circumstances.

Use of Clean, Nonsterile Gloves:

Gloves are worn to provide a protective barrier and to prevent gross contamination of the hands when touching blood, body fluids, secretions, excretions, mucous membranes, and nonintact skin.
The wearing of gloves in specified circumstances to reduce the risk of exposures to bloodborne pathogens is mandated by the OSHA bloodborne pathogens final rule.
Gloves are worn to reduce the likelihood that microorganisms present on the hands of personnel will be transmitted to patients during invasive or other patient-care procedures that involve touching a patient's mucous membranes and nonintact skin.
Gloves are worn to reduce the likelihood that hands of personnel contaminated with microorganisms from a patient or a fomite can transmit these microorganisms to another patient.

In this situation, gloves must be changed between patient contacts and hands washed after gloves are removed.

Wear clean, nonsterile gloves when touching blood, body fluids, secretions, excretions, and contaminated items.
Put on clean gloves just before touching mucous membranes and nonintact skin.
Change gloves between tasks and procedures on the same patient to prevent cross contamination of different body sites.
Remove gloves (1) promptly after use, (2) before touching noncontaminated items and environmental surfaces, and (3) before going to another patient.
Wash hands immediately after removing gloves.
Wearing gloves does not replace the need for handwashing, because gloves may have small, inapparent defects or may be torn during use, and hands can become contaminated during removal of gloves.

Use of Clean, Nonsterile Masks, Eye Protection, Face Shields:

Wear a mask that covers both the nose and the mouth, eye protection (goggles or safety glasses), or a face shield to protect mucous membranes of the eyes, nose, and mouth during procedures and patient-care activities that are likely to generate splashes or sprays of blood, body fluids, secretions, and excretions.
The wearing of masks, eye protection, and face shields in specified circumstances to reduce the risk of exposures to bloodborne pathogens is mandated by the OSHA bloodborne pathogens final rule.
A surgical mask is worn to prevent droplet transmission.

It provides protection against spread of large-particle droplets that are transmitted by close contact and generally travel only short distances (up to 3 ft) from infected patients who are coughing or sneezing.

Use of Clean, Nonsterile Gowns and Protective Apparel:

Wear a clean, nonsterile gown whenever the likelihood of splashes or sprays of blood, body fluids, secretions, and excretions exists.
The type of gown worn should be appropriate for the activity.
Wear a clean, nonsterile gown during procedures that will cause soiling of clothing.
Remove a soiled gown as soon as possible and wash hands.
Gowns especially treated to make them impermeable to liquids, leg coverings, boots, or shoe covers provide greater protection to the skin when splashes or large quantities of infective material are present or anticipated.
The wearing of gowns and protective apparel under specified circumstances to reduce the risk of exposures to bloodborne pathogens is mandated by the OSHA bloodborne pathogens final rule.
Gowns are also worn by personnel during the care of patients infected with epidemiologically important microorganisms (such as MRSA, VRE, VISA, and VRSA) to reduce the opportunity for transmission of pathogens from patients or items in their environment to other patients or environments.

When gowns are worn for this purpose, they are removed before leaving the patient's environment and hands are washed.

Patient-Care Equipment and Articles:

Handle equipment soiled with blood, body fluids, secretions, and excretions in a manner that prevents contamination to yourself, other patients, and environmental surfaces.
Contaminated, reusable critical medical devices or patient-care equipment (i.e., equipment that enters normally sterile tissue or through which blood flows) are sterilized after use to reduce the risk of transmission of microorganisms to other patients.
Contaminated, reusable semicritical medical devices or patient-care equipment (i.e., equipment that touches mucous membranes) are sterilized or disinfected (reprocessed) after use to reduce the risk of transmission of microorganisms to other patients.

The type of reprocessing is determined by the article and its intended use, the manufacturer's recommendations, hospital policy, and any applicable guidelines and regulations.

Contaminated, reusable noncritical equipment (i.e., equipment that touches intact skin) is cleaned and disinfected after use, according to hospital policy.
Contaminated disposable (single-use) patient-care equipment is handled and transported in a manner that reduces the risk of transmission of microorganisms and decreases environmental contamination in the hospital.

The equipment is disposed of according to hospital policy and applicable regulations.

Environmental Control:

There must be adequate procedures for the routine care, cleaning, and disinfection of environmental surfaces and equipment.
Routine cleaning: The day-to-day cleaning of a room while a patient is there.

The room, or cubicle, and bedside equipment of patients on Transmission-Based Precautions are cleaned using the same procedures used for patients on Standard Precautions, unless the infecting microorganism(s) and the amount of environmental contamination indicates special cleaning.
The methods, thoroughness, and frequency of cleaning and the products used are determined by hospital policy.

In addition to thorough routine cleaning, adequate disinfection of bedside equipment and environmental surfaces (e.g., bedrails, bedside tables, carts, commodes, doorknobs, faucet handles) is indicated for certain pathogens, especially Enterococci , which can survive in the inanimate environment for prolonged periods of time.
The process of cleaning after the patient leaves is known as terminal cleaning.

Patients admitted to hospital rooms that previously were occupied by patients infected or colonized with infectious pathogens are at increased risk of infection from contaminated environmental surfaces and bedside equipment if they have not been cleaned and disinfected adequately.

No special precautions are needed for dishes, glasses, cups, or eating utensils.
Either disposable or reusable dishes and utensils can be used for patients on isolation precautions.
The combination of hot water and detergents used in hospital dishwashers is sufficient to decontaminate dishes, glasses, cups, and eating utensils.

Linen and Laundry:

Although soiled linen may be contaminated with pathogenic microorganisms, the risk of disease transmission is negligible if it is handled, transported, and laundered in a manner that avoids transfer of microorganisms to patients, personnel, and environments.
Rather than rigid rules and regulations, hygienic and common sense storage and processing of clean and soiled linen are recommended.
The methods for handling, transporting, and laundering of soiled linen are determined by hospital policy and any applicable regulations.
Used linen (bed sheets, blankets, towels, bibs, diapers, etc) must be handled, transported, and processed in a manner that prevents contamination to yourself, other patients, and environmental surfaces.

Occupational Health and Bloodborne Pathogens:

Care must be taken with needles, scalpels, and all sharp instruments or devices to prevent injuries.
Never recap needles.
Never use techniques which would direct the point of a needle toward any part of your body.
Place used disposable syringes and needles, scalpel blades, and other sharps in puncture-resistant containers located as close as practical to the area of use.
Place reusable syringes in puncture-resistant containers for transport.
Use mouthpieces, resuscitation bags, or other ventilation devices as an alternative to mouth-to-mouth resuscitation.

Patient Placement:

A private room is used to prevent direct- or indirect-contact transmission when the source patient has poor hygienic habits, contaminates the environment, or cannot be expected to assist in maintaining infection control precautions to limit transmission of microorganisms (i.e., infants, children, and patients with altered mental status).
When possible, a patient with highly transmissible or epidemiologically important microorganisms (such as MRSA, VRE, VISA, and VRSA) is placed in a private room with handwashing and toilet facilities, to reduce opportunities for transmission of microorganisms.
When a private room is not available, an infected patient is placed with an appropriate roommate.

Sharing of rooms, referred to as cohorting patients, is useful especially during outbreaks.
Patients infected by the same microorganism usually can share a room, provided they are not infected with other potentially transmissible microorganisms and the likelihood of reinfection with the same organism is minimal.

When an infected patient shares a room with a noninfected patient, it is important that patients, personnel, and visitors take precautions to prevent the spread of infection and that roommates are selected carefully.
A private room with appropriate air handling and ventilation is important for reducing the risk of transmission of microorganisms spread by airborne transmission.
Some hospitals use an isolation room with an anteroom as an extra measure of precaution to prevent airborne transmission.

Transport of Infected Patients:

Limiting the movement and transport of patients infected with virulent or epidemiologically important microorganisms reduces opportunities for transmission of microorganisms in hospitals.
When transport of infected patients is necessary:

Appropriate barriers (e.g., masks, impervious dressings) must be used by the patient to reduce the opportunity for transmission of pertinent microorganisms to other patients, personnel, and visitors and to reduce contamination of the environment.
Personnel in the area to which the patient is to be taken should be notified of the impending arrival of the patient and of the precautions to be used to reduce the risk of transmission of infectious microorganisms.
Patients should be informed of ways by which they can assist in preventing the transmission of their infectious microorganisms to others.

Transmission-Based Precautions:

Transmission-Based Precautions apply to patients known or suspected to be infected with (1) a pathogen which is highly transmissible, and (2) an epidemiologically important pathogen, such as a multidrug-resistant microorganism.
Transmission-Based Precautions are used in addition to Standard Precautions.
This means you employ all Standard Precautions, plus the additional precautions which relate to the situation.
There are three types of Transmission-Based Precautions: (1) airborne, (2) droplet, and (3) contact.

Airborne Precautions:

Are used in addition to Standard Precautions for patients known or suspected to have serious illnesses transmitted by airborne droplet nuclei, such as tuberculosis, measles, and chickenpox. Small, infective particles (less than 5 µm in size) can be free floating or combined with dust particles in the air.

Airborne Precautions Include:

Patient Placement:

The patient is to be placed in a private room that has (1) monitored negative air pressure, (2) six to twelve air changes per hour, and (3) appropriate discharge of the air to the outdoors or monitored filtration of the air before it is circulated (i.e., HEPA or high-efficiency particulate air filter).
The door to the room must be kept closed.
If cohorting (sharing a room) is necessary, patients with an active infection caused by the same microorganism and no other infections may be placed together.

Respiratory Protection:

Approved respiratory masks are to be worn in patient's room whenever airborne precautions are in place.
HEPA and N95 (N category at 95% efficiency) filter respirators meet the CDC performance criteria for tuberculosis respirators.
Susceptible workers should not enter the room of patients with known or suspected measles or chickenpox if other workers are available.

If no other workers are available, susceptible workers are to wear approved respiratory masks.
Persons immune to measles or chickenpox need not wear such masks.

Patient Transport:

The transport of such patients is only for essential purposes.
Patients should wear a surgical mask to prevent dispersal of droplet nuclei.

Tuberculosis:

When tuberculosis is suspected or confirmed, follow CDC Guidelines for Preventing the Transmission of Tuberculosis in Health-Care Facilities.

Droplet Precautions:

Are used in addition to Standard Precautions for patients known or suspected to have serious illnesses transmitted by large-particle droplets, greater than5 µm in size, which can be spread by coughing, sneezing, or talking.
Diseases fitting this category include: invasive Haemophilus influenzae type b (causing meningitis, pneumonia, epiglottitis, and sepsis), invasive Neisseria meningitidis (causing meningitis, pneumonia, and sepsis), diphtheria, Mycoplasma pneumonia, pertussis, pneumonic plague, streptococcal infections (pharyngitis, pneumonia, or scarlet fever), adenovirus, influenza, mumps, parvo virus B19, and rubella.

Droplet Precautions Include:

Patient Placement:

The patient is to be placed in a private room.
If cohorting is necessary, patients with an active infection caused by the same microorganism and no other infections may be placed together.
If private rooms or cohorting are not available options, patients must be separated by at least 3 feet from other patients or visitors. (This is known as the 3-foot rule.)

Mask:

A mask must be worn when working within 3 feet of the patient.

Patient Transport:

The transport of such patients is only for essential purposes.

Patients should wear a surgical mask to prevent dispersal of large-particle droplets.

Contact Precautions:

Are used in addition to Standard Precautions for patients known or suspected to have serious illnesses transmitted by direct patient contact or by contact with patient-care equipment and articles.
These illnesses include:

Multidrug resistant bacteria causing GI, respiratory, skin, or wound infections
Enteric infections involving Clostridium difficile, E. coli O157:H7, Shigella, Salmonella, Hepatitis A, Hepatitis E, Rotavirus, Giardia lamblia, and all other gastroenteral infections which are passed fecal-oral. You will apply contact precautions for all diapered or incontinent patients, irregardless of their age.
RSV (respiratory syncytial virus)
Viral hemorrhagic conjunctivitis
Viral hemorrhagic infections (Ebola, Lassa, or Marburg)
Skin infections involving cutaneous diphtheria, herpes simplex virus, impetigo, major abscesses or cellulitis, pediculosis, scabies, staphylococcal furunculosis, and disseminated zoster.

Contact Precautions Include:

Patient Placement:

The patient is to be placed in a private room.
If cohorting is necessary, patients with an active infection caused by the same microorganism and no other infections may be placed together.

Gloves and Hand Washing:

Wear gloves when entering the room.
Change gloves after having contact with infective material.
Remove gloves before leaving the patient's room and wash hands with an antimicrobial agent or a water less antiseptic agent.
After washing, be certain not to recontaminate hands.

Gown:

Wear a gown when entering the room.
Remove gown before leaving the patient's room. After removing, be certain not to contaminate your clothing.

Patient Transport:

The transport of such patients is only for essential purposes.
Take precautions to prevent transmission to other patients, environmental surfaces, and equipment.

Patient-Care Equipment:

As much as possible, use equipment with a single patient or cohorted patients.
Equipment must be thoroughly cleaned and disinfected before being used with another patient.
There are additional guidelines to be followed when dealing with such drug-resistant organisms as MRSA (methicillin-resistant Staphylococcus aureus ) and VRE (vancomycin-resistant Enterococcus).

New Links to summaries of Standard Precautions, Contact Precautions, Droplet Precautions, and Airborne Precautions:

The CDC has recently added summary links for Standard Precautions, plus the 3 forms of Transmission-Based Precautions: Contact Precautions, Droplet Precautions, and Airborne Precautions. They are an excellent way for you to review the main point of the precautions. Here are the links:

Standard Precautions: http://www.cdc.gov/ncidod/hip/isolat/std_prec_excerpt.htm
Contact Precautions: http://www.cdc.gov/ncidod/hip/isolat/contact_prec_excerpt.htm
Droplet Precautions: http://www.cdc.gov/ncidod/hip/isolat/droplet_prec_excerpt.htm
Airborne Precautions: http://www.cdc.gov/ncidod/hip/isolat/airborne_prec_excerpt.htm

Guideline for Hand Hygiene in Health-Care Settings:

The primary functions of the skin are to reduce water loss, provide protection against abrasive action and microorganisms, and act as a permeability barrier to the environment.
To decontaminate the hands means to reduce bacterial counts on the hands by performing an antiseptic hand rub or antiseptic handwash.
Types of Hand Hygiene:

Hand hygiene is a general term that applies to either (1) handwashing, (2) antiseptic handwash, (3) antiseptic hand rub, or (4) surgical hand antisepsis. In other words, it includes either handwashing or some form of hand antisepsis.
Handwashing is washing hands with plain (non-antimicrobial) soap and water.
Hand antisepsis is a general term that refers to either antiseptic handwash or antiseptic hand rub. In other words, use of an antiseptic (antimicrobial) agent in one form or another.
Antiseptic agent is an antimicrobial substances that are applied to the skin to reduce the number of microbial flora. Examples include alcohols, chlorhexidine, chlorine, hexachlorophene, iodine, chloroxylenol (PCMX), quaternary ammonium compounds, and triclosan. Triclosan is the main ingredient used in antimicrobial soaps.
Antiseptic handwash is washing hands with water and antimicrobial soap or other detergents containing an antiseptic agent.

Antimicrobial soap is a soap (i.e., detergent) containing an antiseptic agent, usually 0.2-2% triclosan.
So if you use an antimicrobial soap at home, you're not just washing your hands, you're performing an antiseptic handwash!

Antiseptic hand rub means applying an antiseptic hand-rub product to all surfaces of the hands to reduce the number of microorganisms present.
Alcohol-based hand rub is an example of an antiseptic hand rub.

It is an alcohol-containing preparation designed for application to the hands for reducing the number of viable microorganisms on the hands.
In the United States, such preparations usually contain 60%--95% ethanol or isopropanol.

Transmission of health-care-associated pathogens from one patient to another via the hands of HCWs requires the following sequence of events:

Organisms present on the patient's skin, or that have been shed onto inanimate objects in close proximity to the patient, must be transferred to the hands of HCWs.
These organisms must then be capable of surviving for at least several minutes on the hands of personnel.
Handwashing or hand antisepsis by the worker must be inadequate or omitted entirely, or the agent used for hand hygiene must be inappropriate.
The contaminated hands of the caregiver must come in direct contact with another patient, or with an inanimate object that will come into direct contact with the patient.

Regulation on Antiseptic Handwash Products:

In the United States, antiseptic handwash products intended for use by HCWs are regulated by the FDA's Division of Over-the-Counter Drug Products ( OTC).
Requirements for in vitro and in vivo testing of HCW handwash products and surgical hand scrubs are outlined in the FDA Tentative Final Monograph for Healthcare Antiseptic Drug Products (TFM).

Shortcomings of Traditional Testing Methods:

Accepted methods of evaluating hand-hygiene products intended for use by HCWs require that test volunteers wash their hands with a plain or antimicrobial soap for 30 seconds or 1 minute, despite the observation in the majority of studies that the average duration of handwashing by hospital personnel is actually <15 seconds.
Methods for evaluating waterless antiseptic agents for use as antiseptic hand rubs require that 3 mL of alcohol be rubbed into the hands for 30 seconds, followed by a repeat application for the same duration. This method does not reflect actual usage patterns among HCWs.

Review of Preparations Used for Hand Hygiene:

Plain (Non-Antimicrobial) Soap

Soaps are detergent-based products that contain esterified fatty acids and sodium or potassium hydroxide.
They are available in various forms including bar soap, tissue, leaflet, and liquid preparations.
Their cleaning activity can be attributed to their detergent properties, which result in removal of dirt, soil, and various organic substances from the hands.
Plain soaps have minimal, if any, antimicrobial activity.
Handwashing with plain soap can remove loosely adherent transient flora.

Alcohols

The majority of alcohol-based hand antiseptics contain either isopropanol, ethanol, n-propanol, or a combination of two of these products.
The antimicrobial activity of alcohols can be attributed to their ability to denature proteins.
Alcohol solutions containing 60%--95% alcohol are most effective, and higher concentrations are less potent because proteins are not denatured easily in the absence of water.
Alcohols have excellent in vitro germicidal activity against gram-positive and gram-negative vegetative bacteria, including multidrug-resistant pathogens (e.g., MRSA and VRE), Mycobacterium tuberculosis ,and various fungi.
Certain enveloped (lipophilic) viruses (e.g., herpes simplex virus, human immunodeficiency virus [HIV], influenza virus, respiratory syncytial virus, and vaccinia virus) are susceptible to alcohols when tested in vitro.
Hepatitis B virus is an enveloped virus that is somewhat less susceptible but is killed by 60%--70% alcohol,
Hepatitis C virus is killed by 60%--70% alcohol.
Alcohols, when used in concentrations present in alcohol-based hand rubs, have in vivo activity against three nonenveloped viruses: rotavirus, adenovirus, and rhinovirus.
Alcohols have poor activity against bacterial spores, protozoan oocysts, and certain nonenveloped (nonlipophilic) viruses.
Alcohols are not appropriate for use when hands are visibly dirty or contaminated with proteinaceous materials.
The effectiveness of alcohol-based hand-hygiene products is determined by several factors:

The type of alcohol used
Concentration of alcohol
Contact time
Volume of alcohol used
Whether the hands are wet when the alcohol is applied

Frequent use of alcohol-based formulations for hand antisepsis can cause drying of the skin unless emollients, humectants, or other skin-conditioning agents are added to the formulations.
Alcohols are both flammable and volatile.

Chlorhexidine

Chlorhexidine gluconate is a cationic bisbiguanide.
The antimicrobial activity of chlorhexidine is likely attributable to attachment to, and subsequent disruption of, cytoplasmic membranes, resulting in precipitation of cellular contents.
Chlorhexidine has good activity against gram-positive bacteria, less activity against gram-negative bacteria and fungi, and only minimal activity against tubercle bacilli.
Chlorhexidine is not sporicidal.
It has in vitro activity against enveloped viruses (e.g., herpes simplex virus, HIV, cytomegalovirus, influenza, and RSV) but substantially less activity against nonenveloped viruses (e.g., rotavirus, adenovirus, and enteroviruses).
Addition of low concentrations (0.5%--1.0%) of chlorhexidine to alcohol-based preparations results in greater residual activity than alcohol alone.

Hexachlorophene

Hexachlorophene is a bisphenol composed of two phenolic groups and three chlorine moieties.
The antimicrobial activity of hexachlorophene results from its ability to inactivate essential enzyme systems in microorganisms.
Hexachlorophene is bacteriostatic, with good activity against S. aureus and relatively weak activity against gram-negative bacteria, fungi, and mycobacteria.
In the early 1970s, certain infants bathed with hexachlorophene developed neurotoxicity. As a result, in 1972, the FDA warned that hexachlorophene should no longer be used routinely for bathing infants. Current guidelines still recommend against the routine bathing of neonates with hexachlorophene because of its potential neurotoxic effects.
Hexachlorophene is classified by FDA TFM as not generally recognized as safe and effective for use as an antiseptic handwash.
Hexachlorophene should not be used to bathe patients with burns or extensive areas of susceptible, sensitive skin.
Soaps containing 3% hexachlorophene are available by prescription only.

Iodine and Iodophors

Iodine has been recognized as an effective antiseptic since the 1800s. Because iodine often causes irritation and discoloring of skin, iodophors have largely replaced iodine as the active ingredient in antiseptics.
Iodine molecules rapidly penetrate the cell wall of microorganisms and inactivate cells by forming complexes with amino acids and unsaturated fatty acids, resulting in impaired protein synthesis and alteration of cell membranes.
Iodophors are composed of elemental iodine, iodide or triiodide, and a polymer carrier (i.e., the complexing agent) of high molecular weight.
The amount of molecular iodine present (so-called "free" iodine) determines the level of antimicrobial activity of iodophors.
"Available" iodine refers to the total amount of iodine that can be titrated with sodium thiosulfate. Typical 10% povidone-iodine formulations contain 1% available iodine and yield free iodine concentrations of 1 ppm.
The antimicrobial activity of iodophors also can be affected by pH, temperature, exposure time, concentration of total available iodine, and the amount and type of organic and inorganic compounds present (e.g., alcohols and detergents).
Iodine and iodophors have bactericidal activity against gram-positive, gram-negative, and certain spore-forming bacteria (e.g., clostridia and Bacillus spp.) and are active against mycobacteria, viruses, and fungi.
In concentrations used in antiseptics, iodophors are not sporicidal.
Povidone-iodine 5%--10% has been tentatively classified by FDA TFM as a Category I agent (i.e., a safe and effective agent for use as an antiseptic handwash and an HCW handwash).
The majority of iodophor preparations used for hand hygiene contain 7.5%--10% povidone-iodine.

Quaternary Ammonium Compounds

Quaternary ammonium compounds are composed of a nitrogen atom linked directly to four alkyl groups.

Alkyl benzalkonium chlorides are the most widely used as antiseptics.
Other compounds that have been used as antiseptics include benzethonium chloride, cetrimide, and cetylpyridium chloride.

The antimicrobial activity of this group of compounds involves adsorption to the cytoplasmic membrane, with subsequent leakage of low molecular weight cytoplasmic constituents.
Quaternary ammonium compounds are primarily bacteriostatic and fungistatic.
They are more active against gram-positive bacteria than against gram-negative bacilli.
Quaternary ammonium compounds have relatively weak activity against mycobacteria and fungi and have greater activity against lipophilic viruses.
Because of weak activity against gram-negative bacteria, benzalkonium chloride is prone to contamination by these organisms. Several outbreaks of infection or pseudoinfection have been traced to quaternary ammonium compounds contaminated with gram-negative bacilli.

Triclosan

Triclosan (chemical name: 2,4,4'-trichloro-2'-hydroxy-diphenyl ether) is a nonionic, colorless substance.
It has been incorporated into soaps for use by HCWs and the public and into other consumer products.
Concentrations of 0.2%--2% have antimicrobial activity.
Triclosan enters bacterial cells and affects the cytoplasmic membrane and synthesis of RNA, fatty acids, and proteins.

Activity of Antiseptic Agents Against Spore-Forming Bacteria:

The widespread prevalence of healthcare-associated diarrhea caused by Clostridium difficile, and the recent occurrence in the United States of human Bacillus anthracis infections associated with contaminated items sent through the mail, has raised concern regarding the activity of antiseptic agents against spore-forming bacteria.
None of the agents (including alcohols, chlorhexidine, hexachlorophene, iodophors, PCMX, and triclosan) used in antiseptic handwash or antiseptic hand-rub preparations are reliably sporicidal against Clostridium spp. or Bacillus spp.
Washing hands with non-antimicrobial or antimicrobial soap and water may help to physically remove spores from the surface of contaminated hands.
HCWs should be encouraged to wear gloves when caring for patients with C. difficile-associated diarrhea.

Other Policies Related to Hand Hygiene:

Fingernails and Artificial Nails:

The subungual areas of the hand harbor high concentrations of bacteria, most frequently coagulase-negative staphylococci, gram-negative rods (including Pseudomonas spp.), Corynebacteria, and yeasts.
Freshly applied nail polish does not increase the number of bacteria recovered from periungual skin, but chipped nail polish supports the growth of larger numbers of organisms on the fingernails.
HCWs who wear artificial nails are more likely to harbor gram-negative pathogens on their fingertips than are those who have natural nails, both before and after handwashing

Jewelry:

Skin underneath rings is more heavily colonized than comparable areas of skin on fingers without rings.
One study found that 40% of nurses harbored gram-negative bacilli (e.g., E. cloacae, Klebsiella, and Acinetobacter ) on skin under rings and that certain nurses carried the same organism under their rings for several months.

New Recommendations - Indications for Handwashing and Hand Antisepsis:

When hands are visibly dirty or contaminated with proteinaceous material or are visibly soiled with blood or other body fluids, wash hands with either a non-antimicrobial soap & water or an antimicrobial soap & water.
If hands are not visibly soiled, use an alcohol-based hand rub for routinely decontaminating hands.
Decontaminate hands:

Before having direct contact with patients.
Before donning sterile gloves when inserting a central intravascular catheter.
Before inserting indwelling urinary catheters, peripheral vascular catheters, or other invasive devices that do not require a surgical procedure.
After contact with a patient's intact skin (e.g., when taking a pulse or blood pressure, and lifting a patient).
After contact with body fluids or excretions, mucous membranes, nonintact skin, and wound dressings if hands are not visibly soiled.
If moving from a contaminated-body site to a clean-body site during patient care.
After contact with inanimate objects (including medical equipment) in the immediate vicinity of the patient.
After removing gloves.
Before eating and after using a restroom, wash hands with a non-antimicrobial soap & water or with an antimicrobial soap & water.

Antimicrobial-impregnated wipes (i.e., towelettes) may be considered as an alternative to washing hands with non-antimicrobial soap & water.
Wash hands with non-antimicrobial soap & water or with antimicrobial soap & water if exposure to Bacillus anthracis is suspected or proven.

Hand-Hygiene Technique:

When decontaminating hands with an alcohol-based hand rub, apply product to palm of one hand and rub hands together, covering all surfaces of hands and fingers, until hands are dry. Follow the manufacturer's recommendations regarding the volume of product to use.
When washing hands with soap and water , wet hands first with water, apply an amount of product recommended by the manufacturer to hands, and rub hands together vigorously for at least 15 seconds, covering all surfaces of the hands and fingers. Rinse hands with water and dry thoroughly with a disposable towel. Use towel to turn off the faucet. Avoid using hot water, because repeated exposure to hot water may increase the risk of dermatitis.

Surgical Hand Antisepsis:

Remove rings, watches, and bracelets before beginning the surgical hand scrub.
Remove debris from underneath fingernails using a nail cleaner under running water.
Surgical hand antisepsis using either an antimicrobial soap or an alcohol-based hand rub with persistent activity is recommended before donning sterile gloves when performing surgical procedures.
When performing surgical hand antisepsis using an antimicrobial soap, scrub hands and forearms for the length of time recommended by the manufacturer, usually 2-6 minutes. Long scrub times (e.g., 10 minutes) are not necessary.
When using an alcohol-based surgical hand-scrub product with persistent activity, follow the manufacturer's instructions. Before applying the alcohol solution, prewash hands and forearms with a non-antimicrobial soap and dry hands and forearms completely. After application of the alcohol-based product as recommended, allow hands and forearms to dry thoroughly before donning sterile gloves.

Skin Care:

Provide HCWs with hand lotions or creams to minimize the occurrence of irritant contact dermatitis associated with hand antisepsis or handwashing.
Solicit information from manufacturers regarding any effects that hand lotions, creams, or alcohol-based hand antiseptics may have on the persistent effects of antimicrobial soaps.

Other Aspects of Hand Hygiene:

Do not wear artificial fingernails or extenders when having direct contact with patients at high risk (e.g., those in intensive-care units or operating rooms).
Keep natural nails tips less than 1/4-inch long).
Wear gloves when contact with blood or other potentially infectious materials, mucous membranes, and nonintact skin could occur.
Remove gloves after caring for a patient. Do not wear same pair of gloves for the care of more than one patient, and do not wash gloves between uses with different patients.
Change gloves during patient care if moving from a contaminated body site to a clean body site.
No recommendation can be made regarding wearing rings in health-care settings.

Based on what has been learned through research and practice, the current recommendation with regard to hand hygiene in healthcare is:

Begin with washing hands with plain soap to remove dirt and debris.
In between hand washing with plain soap, clean hands using alcohol-based hand gels.

Alcohol-based hand gels may be used to clean the hands between several activities or patient contacts.
Alcohol-based hand gels may be used before and after gloving to perform routine activities and procedures.

Wash hands with plain soap whenever hands are visibly dirty or begin to feel gritty (i.e., as if there is a build-up of the gel on them).

Alcohol loses its effectiveness in the presence of dirt and organic matter.

Use hand lotions to support good skin health.

Make certain the lotion is not contaminated.
Lotions used with products containing chlorhexidine gluconate (CHG) must be selected to avoid neutralization by anionic surfactants.

Based on what has been learned through research and practice, current recommendation in clinical areas such as operating rooms and neonatal and transplant units is:

Shorter, less traumatic washing regimens may be used instead of lengthy scrub protocols with brushes or other harsh mechanical action.

Hand Washing:

The purpose of hand washing is to remove dirt, organic matter, and transient microorganisms.
Transient flora do not normally colonize the skin (i.e., multiply in high numbers) and the types of transient flora found on the skin vary from person to person.
These transient flora can be transmitted by a health care worker's hands unless they are removed by proper hand washing.
Proper hand washing includes mechanical friction, use of appropriate soap, proper rinsing and drying.
The facility you work in will determine when a plain soap is OK and when an antimicrobial soap (or water-less antiseptic agent) is required.
Washing:

Use warm water.
Your dampened hands should be thoroughly covered with the hand washing substance (3 to 5 ml is recommended), then rubbed vigorously for 10 to 15 seconds, generating friction on all surfaces of the hands and fingers.
Fingernails should be thoroughly cleaned. Washing should proceed from the tips of the fingers up to and including the wrists.

Rinsing:

Use warm water.
Rinsing should begin from the fingertips downward to the wrists.
Hands should be thoroughly rinsed to remove soap and debris. (Note: Some hand washing procedures include the cleansing of the forearms.)

Drying:

Hands should be dried using paper towels.
Drying should proceed from the tips of the fingers up to and including the wrists.
A paper towel should be used to turn off the faucet, trying not to contaminate the hands.
Sinks with foot controls or automatic shutoff are best.
Warm-air dryers are used in public rest rooms, but are rarely employed in the health care setting.

These type of dryers dry the hands slowly, often have timed cycles that are too brief, can only be used by one person at a time, and could cause organisms to be blown back onto the hands.

Hand Antisepsis:

The purpose of hand antisepsis is to remove or destroy transient microorganisms.
There are two ways hand antisepsis can occur:

During hand washing by using a soap or detergent containing an antiseptic ingredient in an appropriate concentration.
By using an alcohol-containing antiseptic handrub on clean hands.

Hand antisepsis using alcohol:

This process requires the hands already be free of dirt.
Alcohol is not a good cleaning agent, losing its effectiveness in the presence of dirt and organic matter.

The recommended method:

Thoroughly wet pre-cleaned hands with an alcohol solution.
Vigorously rub the hands for one minute, generating friction on all surfaces of the hands and fingers.
60% to 70% ethanol or isopropyl alcohol preparations, containing emollients to minimize skin drying, are considered the best.
The technique is only effective if a sufficient amount of alcohol, of an appropriate concentration, is used.

From assignment, Physical & Chemical Control:

Sterilization & Disinfection - Terminology:

Sterilization is the complete elimination or destruction of all forms of microbial life. It can be accomplished by physical or chemical means. Objects must first be cleaned before they can be successfully sterilized.
Disinfection is a process that eliminates many or all pathogenic microorganisms, except for bacterial spores, from inanimate objects. Objects must first be cleaned before they can be successfully disinfected.
Cleaning is the removal of all foreign material, such as soil or organic material, from an object. It is normally accomplished with water, mechanical action, and detergents or enzymatic products.
A germicide is a generic name for a disinfectant that kills "germs." (Unspecified what the germs really are!)

A bactericide kills bacteria. (Unspecified which bacteria really are killed!)
A virucide kills viruses. (Unspecified which viruses really are killed!)
A fungicide kills fungi. (Unspecified which fungi really are killed!)
A sporicide kills spores. (Unspecified to what degree bacterial endospores really are killed!)

Sterilants are chemicals used to kill all microbial life on inanimate objects. The FDA (Food and Drug Administration) regulates sterilants.

Sterilants are high-level disinfectants which are being used in such a way as to create sterilization, usually by increasing the exposure time to the chemical and/or concentration of chemical.
It usually requires 6-10 hours of soaking time in the chemical in order to kill endospores.

Disinfectants kill some, but not all, microbial life on inanimate objects. The EPA (Environmental Protective Agency) regulates disinfectants.
Antiseptics are chemicals safe to use on human skin and tissue to kill some, but not all, microbial life. They should not be used to disinfect inanimate objects. The FDA (Food and Drug Administration) regulates antiseptics.
Pasteurization is the process of heating food or other substances under controlled conditions of time and temperature to kill pathogens and reduce the total number of mircroorganisms without damaging the substance.

Sterilization Methods:

The three major sterilizing agents used in hospitals and other healthcare settings are: autoclaving (moist heat under pressure), dry heat sterilization, and ethylene oxide (ETO).

ETO is rarely used any more. Ionizing radiation is often used instead of ETO.

Boiling is not an effective means of achieving sterilization because it does not kill endospores.
Autoclave: The most common setting for use is: 121C for 15-20 minutes at 15 psi.

The autoclave used moist heat under pressure to achieve sterilization.
The autoclave can damage heat-sensitive materials.
Autoclaving must allow for drying of items at the end of its cycle. If not, moist items could again become contaminated.

Flash sterilization is used in emergency situations only. The autoclave setting is 135C for 10 minutes at 15 psi. Increasing the temp decreases the required time needed to achieve sterilization.
Dry Heat Sterilization: The most common setting is: 200C for 1 1/2 hours.

It requires increased temps and times as compared to moist heat sterilization.

Ethylene Oxide (ETO) is a gaseuous sterilizing agent used for commercial and medical applications.

It is explosive and must be mixed with an inert gas such as carbon dioxide. Gas leaks are a medical emergency.
It is effected by temperature and humidity.
Requires 3-12 hours to achieve sterilization. Toxic residue must be removed for objects, which may require an additional 8-12 hours.

Ionizing Radiation involves the use of gamma radiation.

As normally used, ionizing radiation does not sterilize, as it doesn’t destroy endospores.

Increasing the dosage and exposure time can lead to sterilization.

Normally, ionizing radiation is used to pasteurize food products, such as poultry, beef, lamb, pork, fruit, vegetables, grains, spices, and herbs.

UV Radiation involves the use of ultraviolet light to kill bacteria by damaging the bacterial DNA.

Thymine dimers are formed within the DNA from adjacent thymine molecules.
UV light cannot penetrate grease, plastic, glass, etc. and, therefore, is NOT an effective method for sterilization.
UV light is harmful to the eyes and skin and can promote the development of skin cancer.

Biological Indicators:

Biological indicators are used to ensure autoclaves are sterilizing.

A tube containing the endospores of Bacillus stearothermophilus is placed in the autoclave with a regular load.
The tube also contains growth media in a separate container. After autoclaving, the container is crushed, exposing the endospores to the growth media, and then allowed to incubate.
If the media changes color after incubating, that means the endospores were able to survive in the autoclave, then germinated and grew in the incubator. This would mean the autoclaving did NOT work!

The genus-species name of the indicator organism recommended for testing of steam sterilizers (autoclaves) is Bacillus stearothermophilus.
The genus-species-strain name of the indicator organism recommended for testing of dry heat sterilizers is Bacillus subtilis var. niger.
The genus-species-strain name of the indicator organism recommended for testing of ethylene oxide sterilizers is Bacillus subtilis var. niger.

Factors Effecting the Disinfection Process:

Previous cleaning of the object
Organic load on the object
The type and level of microbial contamination
The concentration of and exposure time to the disinfectant
The condition of the object (grooves, crevices, hinges, lumens, etc)
The temperature and pH of the disinfection process

Order of Resistance of Microorganisms:

Order of resistance of microorganisms to chemical disinfectants from most to least resistant:

bacterial endospores (most resistant)
mycobacteria
nonlipid (non-enveloped) viruses
fungi
vegetative bacteria
lipid (enveloped) viruses (least resistant)

Levels of Disinfection:

High-level disinfection destroys all microorganisms and some bacterial endospores.
Intermediate-level disinfection destroys mycobacteria, vegetative bacteria, most viruses, most fungi, but not bacterial endospores.
Low-level disinfection destroys most vegetative bacteria, some viruses, some fungi, but not mycobacteria and not bacterial endospores.

Spaulding's Classification System of Healthcare Items

Critical Care Items: Items which enter sterile tissue or the vascular system. Include items such as implants, scalpels, needles, cardiac and urinary catheters, and other surgical instruments. These items must be processed by sterilization.
Semicritical Care Items: Items which come in contact with mucous membranes or non-intact skin. Include items such as respiratory therapy and anesthesia equipment, flexible endoscopes, cervical diaphragm fitting rings, laryngoscopes, and endotracheal tubes. These items must be processed by high-level disinfection. It is recommended that semicritical items be rinsed with sterile water after disinfection. Semicritical items, such as thermometers and hydrotherapy tanks, only require intermediate-level disinfection.
Noncritical Care Items: Items which come in contact with intact skin but not mucous membranes. Include bedpans, blood pressure cuffs, crutches, bed rails, linens, some food utensils, bedside tables, wheelchairs, and patient furniture. These items are processed by low-level disinfection.

Types of Chemical Disinfectants:

Alcohol:

The maximum microbicidal activity of alcohol is achieved when its concentration is between 50%-80% (or 60%-90%).
Alcohol can be used as an intermediate-level disinfectant. It's use is limited by its disadvantages (given below).
Alcohols can be used effectively as antiseptics for skin preparation of injection sites.
Alcohol-based hand gels are recommended for handwashing in healthcare settings, in between washing with nonantimicrobial soaps.

Alcohol is inactivated by organic matter, such as bodily secretions and excretions (blood, urine, feces, etc.). Hands need to be washed whenever there is exposure to such substances.

They function by denaturing proteins.
Alcohols leave no residue, are relatively nontoxic, are easy to obtain, and are inexpensive.
Alcohols are volatile, they evaporate quickly not allowing for extended contact time, and do not kill endospores.

Chlorine:

Is an intermediate-level disinfectant.
It functions by oxidizing proteins and nucleic acids.
It is effective, convenient, and inexpensive.
It may be corrosive and can be inactivated by organic molecules.
Its high pH decreases its effectiveness.
Solutions used in healthcare must be made up fresh daily.
It reacts with many organics to form carcinogenic (cancer-causing) compounds.
Its common uses include glassware and surface disinfection, water and wastewater treatment, and to disinfect food-processing equipment.

Iodine Tincture:

Is an intermediate-level disinfectant.
It functions by oxidizing proteins.
It is not as quickly inactivated by organic molecules as is chlorine.
It is effective at a wide pH range.
It may be corrosive and can be inactivated by organic molecules.
It stains instruments, clothing, and the skin.
It is painful on nonintact skin.
It is used for small-scale drinking water treatment and as a skin antiseptic.

Iodophors:

Is a low to intermediate-level disinfectant.
It functions by oxidizing proteins.
It is less corrosive and less staining, but also less effective, than iodine tinctures.
It is essential that it be used in proper dilution.
Pseudomonas aeruginosa can grow in and contaminate some iodophor solutions.
Is used as a skin antiseptic.

Phenolics:

Is a low to intermediate-level disinfectant.
It functions by destroying cell membranes and denaturing proteins.
It remains active in the presence of organics.
Are irritating to tissue.
Leave a toxic residue.
Create toxic vapors.
Is used to clean surfaces.

Chlorhexidine:

Is a low to intermediate-level disinfectant.
Is a phenol derivative commonly used for surgeons' hand scrubs, for disinfecting patients' skin prior to an operation, and as a wound cleanser.
It works well against Staphylococci, plus is effective against many gram-negative organisms.
Sold under brand names such as Hibitane and Hibiclens.

QUATS (Quaternary Ammonium Compounds):

Is a low-level disinfectant.
It functions by destroying cell membranes.
It is inexpensive.
It is readily inactivated by detergents, fibers, and other compounds.
Pseudomonas aeruginosa can grow in and contaminate some QUAT solutions.
It is used to clean surfaces, in the food industry, and in general housekeeping.

Glutaraldehyde:

Can be used as a sterilant if a treatment time of 10-12 hours is employed.
Have intermediate to high activity level.
Are commonly used for high level disinfection at a 1.0-1.5% MEC (minimum effective concentration).
Is noncorrosive to metal and does not damage lensed instruments, rubber, or plastics.
Should not be used for noncritical items because too toxic and expensive.
Create toxic vapors. Ceiling limit cannot exceed 0.2 ppm. 7 to 15 air exchanges per hour provide proper ventilation.
Workers should wear PPE, including nitrile rubber, butyl rubber, or polyethelyne gloves and gogles to minimize skin or mucous membrane contact.

Hydrogen peroxide:

It functions by creating hydoxyl free radicals which destroy cell membranes, DNA, and other cell components.
3% hydrogen peroxide is used as a skin antiseptic.
3-6% hydrogen peroxide is a stable and effective disinfectant.
6-25% hydrogen peroxide concentrations can be used as chemical sterilants.
The STERRAD 200 Sterilization System uses low-temperature hydrogen peroxide gas plasma technology.

This combination process allows medical instruments to be sterilized.

Peracetic Acid:

Is characterized by rapid action against all microorganisms, including bacterial endospores, and can be used as a chemical sterilant.
It remains effective in the presence of organics.
It functions by destroying cell membranes and denaturing proteins.
Can corrode copper, brass, bronze, plain steel, and galvanized iron.
Is unstable when diluted.

From assignment, Gram Positive Bacteria:

Gram Positive Cocci:

The three main Gram positive cocci are: Staphylococcus, Streptococcus, and Enterococcus .
Staphylococci :

Staphylococci are divided into two major groups based on the coagulase test:

Coagulase positive (CoPS), includes Staphylococcus aureus.
Coagulase negative (CoNS) includes all other species of staph, including Staphyloccus epidermidis, S. saprophyticus , and S. haemolyticus.

30% of people carry S. aureus as normal flora of their nose.
Staph species colonize skin, external eye, external ear, and mucous membranes.
Staphylococcus aureus is the main cause of staph infections. Infections vary from skin infections to serious progressive, invasive diseases.
Microscopically, Staphylococcus is a genus of Gram-positive, nonmotile, nonsporing cocci. They are 0.5 - 1.5 micrometers (mm) in size and occur in grapelike clusters. Sometimes those clusters are disturbed by the staining process, leaving staphylococci in singles, pairs, short chains, and tetrads, along with the clusters.
We are most interested in three species of the genus Staphylococcus: S. aureus, S. epidermidis, and S. saprophyticus. When seen as colonies on Petri plates, all staph colonies are 1-3 mm in diameter. They are opaque, smooth, convex, and circular. They have a butyrous (buttery) appearance.

Colonies of Staphylococcus aureus are usually yellow to orange to white, plus they show beta-hemolysis on a blood agar plate.
Colonies of Staphylococcus epidermidis are usually gray-white and are nonhemolytic (called gamma-hemolysis) on a blood agar plate.
Colonies of Staphylococcus saprophyticus are often yellow to orange and are also nonhemolytic on a blood agar plate.

Staphylococci and Streptococci are distinguished using the catalase test:

Staph are catalase positive while Strep are catalase negative.
This test demonstrates the ability of a bacterium to produce the enzyme, catalase, capable of converting hydrogen peroxide (produced as part of oxygen usage) to water and oxygen. Add several drops of 3% hydrogen peroxide drop-by-drop in the tube. In a positive test, bubbling occurs along the streak. The bacterium is aerobic or facultatively anaerobic. As part of its oxygen usage, it has produced hydrogen peroxide. It then produced catalase enzyme to break down the hydrogen peroxide to water and oxygen. In a negative test, no bubbling occurs.

Streptococci :

Microscopically, Streptococcus is a genus of Gram-positive, nonmotile, nonsporing cocci. They are 0.5 - 2.0 micrometers in size and occurs in pairs or chains. Often, especially in a young culture, they will appear elongated, ovoid to rodlike in shape.
- We are most interested in four species of the genus Streptococcus: S. pyogenes, S. pneumoniae, S. mutans, and S. sanguis.
- All Strep colonies are small, being around 0.5 mm in diameter. When seen as colonies on Petri plates, they are transparent to opaque, smooth, and circular.
- All Strep colonies are coagulase negative.

Beta-hemolytic Strep.

Beta-hemolytic Strep include Lancefield Groups A (Streptococcus pyogenes), B ( Streptococcus agalactiae ), C, F, and G.

Alpha-hemolytic Strep.

Alpha-hemolytic Strep include Streptococcus pneumoniae and the viridans strep ( S. mutans, S. salivaricus, S. sanguis, S. mitis, and S. oralis ).

Group A Strep ( Streptococcus pyogenes) are not usually considered part of a person's normal flora. They are the main cause of strep infections, especially strep throat (streptococcal pharyngitis).

Distinguishing Between Staphylococci and Streptococci
.	Staphylococci	Streptococci
Catalase Test	(+)	(-)
MSA: Growth in 7.5% NaCl	(+)	(-)

Distinguishing Between Species of Staphylococci
.	*S. aureus*	*S. epidermidis*	*S. saprophyticus*
Coagulase results	Coag-positive	Coag-negative	Coag-negative
Hemolytic pattern	Beta-hemolytic	Nonhemolytic	Nonhemolytic
MSA results	Ferments mannitol	Does not ferment mannitol	Some strains ferment mannitol

Enterococci:

Enterococcus faecalis and Enterococcus faecium are the two most common species of Enterococci.

Enterococci are found as normal flora of the skin, mucous membranes, and GI tract.
Nosocomial infections involving Enterococci include UTIs, wound infections, intra-abdominal infections, and bloodstream infections.

Gram Positive Bacilli:

Listeria monocytogenous is the most common species of Listeria associated with human disease.
Listeria can resist cold and salt, which allows them to survive through the processing and storage of food products.
Listeria monocytogenous can cause bloodstream infections and meningitis in neonates and immunocompromised patients. In pregnant women, infections can result in abortion, still birth, or premature birth.
Corynebacterium diphtheriae causes diphtheria. Due to the administration on the DTaP vaccine, diphtheria is very rare in the United States.
Facts about Anthrax:

Bacillus anthracis is the cause of anthrax. Anthrax is a disease usually associated with animals that can spread to humans in close contact with infected animals.
Bacillus anthracis has been implicated in biological warfare.
The endospores gain entry through cuts or through mucous membranes.
Human infections usually occur in workers whose occupations expose them to infected animals (ex: farmers, veterinarians, and slaughter house personnel) or animal products (hides, wook, or hair).
The infection begins as lesions, then spreads through the lymphatic system to the bloodstream.
5 to 20% of untreated cases result in death.

Signs and symptoms of Anthrax:

Symptoms of disease vary depending on how the disease was contracted, but symptoms usually occur within 7 days.
Cutaneous anthrax is the most common naturally occurring type of infection (>95%) and usually occurs

after skin contact with contaminated meat, wool, hides, or leather from infected animals. The incubation period ranges from 1-12 days. The skin infection begins as a small papule, progresses to a vesicle in 1-2 days followed by a necrotic ulcer. The lesion is usually painless, but patients also may have fever, malaise, headache, and regional lymphadenopathy. Most (about 95%) anthrax infections occur when the bacterium enters a cut of abrasion on the skin. Skin infection begins as a raised bump that resembles a spider bite, but (within 1-2 days) it develops into a vesicle and then a painless ulcer, usually 1-3 cm in diameter, with a characteristic black necrotic (dying) area in the center. Lymph glands in the adjacent area may swell. About 20% of untreated cases of cutaneous anthrax will result in death. Deaths are rare if patients are given appropriate antimicrobial therapy.

Inhalational anthrax is the most lethal form of anthrax. Anthrax spores must be aerosolized in order to cause inhalational anthrax. The number of spores that cause human infection is unknown. The incubation period of inhalational anthrax among humans is unclear, but it is reported to range from 1 to 7 days, possibly ranging up to 60 days. It resembles a viral respiratory illness and initial symptoms include sore throat, mild fever, muscle aches and malaise. These symptoms may progress to respiratory failure and shock with meningitis frequently developing.
Gastrointestinal anthrax usually follows the consumption of raw or undercooked contaminated meat and has an incubation period of 1-7 days. It is associated with severe abdominal distress followed by fever and signs of septicemia. The disease can take an oropharyngeal or abdominal form. Involvement of the pharynx is usually characterized by lesions at the base of the tongue, sore throat, dysphagia, fever, and regional lymphadenopathy. Lower bowel inflammation usually causes nausea, loss of appetite, vomiting and fever, followed by abdominal pain, vomiting blood, and bloody diarrhea.

Foodborne Intoxication and Foodborne Infection:

Foodborne intoxication results when a person eats a food product containing an already-produced exotoxin.

The exotoxin was produced by bacteria living and reproducing in the food product before it was consumed.
The exotoxin is causing the rapid development of the illness in the person.
Symptoms can appear within hours of consumption.
Staphylococcus aureus and Clostridium botulinum produce foodborne intoxication.

The toxin produced by S. aureus is heat-stable, so is not destroyed by cooking or boiling the food.
The toxin produced by C. botulinum is heat-labile, so would be destroyed by boiling the food for 15 minutes immediately before consumption.

Foodborne infection results when a person eats a food product containing living microorganisms.

Symptoms usually don't appear until after 24 hours of consumption.
Proper cooking of food will kill microorganisms living in the food, thus preventing infection.
However, properly cooked food can be contaminated with microorganisms by food preparers after cooking is completed.
For foodborne infection by Clostridium perfringes to develop, the patient has to eat food which has been contaminated with the Clostridial organisms. The toxin released acts upon the gastrointestinal system (i.e., as an enterotoxin) causing abdominal pain and diarrhea. It is usually a self-limiting illness, resolving over time without treatment.

Key points for anaerobic infections:

Foul odor.
Mixed infections.
Abscess formation.
Endogenous (from the person's own flora).

Facts about endospores and endospore-forming bacteria:

The two genera Gram-positive endospore-forming bacteria Bacillus and Clostridium.

Clostridia are anaerobes.
Bacilli are aerobes or facultative anaerobes.

When the endospores enter into a favorable environment, such as the human body, they undergo germination to their natural growing stage, known as the vegetative cells. These grow and reproduce, colonizing and infecting the person.
Endospores can survive heat, lack of water, antimicrobial agents, chemicals and disinfectants, sunlight, ultraviolet radiation, and boiling.

Endospores are a survival mechanism. It is not a reproductive process. There is no increase in cell numbers.
Endospores form within a vegetative cell. One vegetative cell forms one endospore in order to survive, which germinates into one vegetative cells when environmental conditions are again favorable.
Endospores form by a process called sporulation, also known as sporogenesis.
Endospores return to vegetative cells by a process called germination.

Only autoclaving (when done correctly) can kill all endospores.

When autoclaving is not possible, sporicidal disinfectants should be used to kill endospores. They will kill most, but not all, of the endospores.

Mixed infections involve anaerobes and facultative anaerobes.

The facultative anaerobes use up the oxygen, allowing for growth of the anaerobes.
This often leads to the formation of an abscess.

An abscess is a localized accumulation of pus in a tissue.

The pus is a combination of the bacteria growing and reproducing in the area and the response of the immune system cells.
The bacteria in a mixed infection attempt to "wall themselves off" further removing the oxygen from the area.

Sterilization of Endospores:

Today, the "golden standard" for achieving sterilization is through autoclaving.
Sterilization is a process by which we remove all microorganisms, including endospores, from an object. Once treated, the object is considered to be sterile.
Autoclaving involves the use of moist heat under pressure.
Typical autoclave settings are 121°C at 15 psi for 15-20 minutes.
Chemical and biological indicators can be used to ensure the autoclave is working properly.
A common chemical indicator is specialized tape. It has diagonal marks that will turn black when the correct temperature is reached in the autoclave.
The most common biological indicator is Bacillus stearothermophilus , which produces heat-resistant spores. After autoclaving, the endospores are mixed with growth media and placed in an incubator. If the endospores were not killed during the autoclave process, they will germinate. This would mean the autoclave wasn't working! So lack of growth is the hoped for result!

Actinomyces:

Clinical sites of infection and predisposing condition include:

Face - poor dental hygiene, dental surgery, or injury.
Abdomen - surgery or injury.
Chest - pulmonary infection involving aspiration from the lungs.
Female genital tract - IUD (intrauterine device).

Actinomycosis (or Lumpy Jaw):

Actinomyces israelii is responsible for antinomycosis.
A. israelii is a Gram positive, slow-growing, nonmotile, non-sporing, filamentous, branching, anaerobic to facultative anaerobic bacterium.
A. israelii inhabits the mouth and gingiva.
Actinomycosis is slowly progressive. There can be painful swellings (abscesses) under the skin, in the area of the jaw or neck, that eventually open and drain. The sores may heal, reappear, and drain for weeks, creating cycles of abscess formation and scarring.
Many cases follow dental surgery.
Penicillin and tetracycline are used to treat, and must be administered for extended periods, because the bacteria are so slow-growing.
Proper care must be taken following surgery, especially dental or oral surgery, to prevent this disease.

Foodborne Botulism:

Clostridium botulinum is responsible for the disease botulism. Most botulism is foodborne. However, there is also wound botulism and infant botulism.
Foodborne Botulism does not occur frequently in the United States. When it does, it is usually associated with home-canned or home-processed foods such as vegetables, fish, meats, or potato salad.
The endospores of C. botulinum were within the food when it was processed. Due to poor processing, they were not destroyed. They were allowed to germinate into vegetative cells.
Botulism involves the production of a powerful neurotoxin by the vegetative cells.

The neurotoxin has already been produced in the contaminated food, and is ingested along with the food. Therefore, this disease is referred to as foodborne intoxication (i.e., the toxin was eaten).

Botulism is an example of a disease that involves a tox gene carried by prophage (i.e., viral DNA intergrated into the bacterial chromosome during lysogenic cycle).

The toxin, which is the virulence factor for this disease, is only produced when lysogenic conversion has occurred.
This means that the gene to code for the production of the toxin, known as the tox gene, is really a bacteriophage gene.
So the disease only occurs when the bacterium itself is infected with the specific bacteriophage which codes for the production of the toxin, and the phage has incorporated itself into the bacterium's chromosome, known as the prophage stage.
There are seven types of botulism toxin designated by the letters A through G; only types A, B, E and F cause illness in humans.

Symptoms begin within 12-36 hours after ingestion, but they can occur as early as 6 hours or as late as 10 days.
The neurotoxin binds to nerve endings blocking the release of acetylcholine, the neurotransmitter present at neuromuscular junctions.
Intestinal symptoms usually occur first, and become quite severe.
These are symptoms of the muscle paralysis caused by the bacterial toxin:

Double vision, blurred vision, drooping eyelids, slurred speech, difficulty swallowing, dry mouth, and muscle weakness.
Infants appear lethargic, feed poorly, are constipated, have a weak cry and poor muscle tone.

If left untreated, vital muscles of the circulatory and respiratory systems stop functioning, leading to the death of the individual.

Boiling foods at 100 C for at least 10 minutes will inactivate the neurotoxin.
The best prevention is to check foods thoroughly for possible contamination (bulging cans, unusual surface film, etc).
Do not taste foods to determine if they are contaminated! The amount of food ingested from a licked spoon has been enough to cause serious illness!
Treatment involves the use of preformed antitoxin, which is a special form of antibody against the neurotoxin, along with supportive therapy.
There are no vaccines available against botulism.

Infant Botulism:

Infant Botulism is becoming the most common form of botulism in the US.
It affects infants during their first year of life.
It has been associated with the use of honey, which can contain bacterial endospores of C. botulinum .
Older children and adults, with fully functioning immune systems, seem to "fight off" the effects of the toxins released by germinating endospores acquired from the honey.
Immunocompromised persons are also at risk of this infection.

Gas Gangrene (or Clostridial Myonecrosis):

Clostridium perfringes is responsible for the disease gas gangrene, plus it can cause a form of food poisoning.

Clostridium perfringens is widespread in soil, the feces of humans and animals, and in the vagina of 1 to 9% of healthy women.

Gas Gangrene (or Clostridial Myonecrosis) is associated with surgical wounds, injury, and severe burns.

Persons with poor cardiovascular or pulmonary function, such as diabetics, are at greatest risk.
Gas gangrene occurs in neglected battlefield wounds and occasional surgical wounds.
Gas gangrene of the uterus can occur in self induced abortions, and rarely after miscarriages and childbirth.

There has to be an opening by which the endospores enter the person's body. Within the person's body, an anaerobic (or low oxygen) environment must be present in order for germination to occur.
Symptoms usually appear within one to four days. There is severe pain at the site of the injury and the wound displays gaseous, discolored, and often smelly tissue destruction.
Treatment involves debridement of the wound, antibiotics, supportive therapy, and the use of hyperbaric oxygen.
If necessary, an infected limb will have to be removed. This disease usually affects limbs (preferably legs) due to the poor circulation in the peripheral system.
There are no vaccines or antitoxins available.

Pseudomembranous Colitis & AAC (or Clostridium difficile Colitis or Antibiotic-Associated Colitis):

Clostridium difficile is responsible for two forms of colitis known as Pseudomembranous Colitis and AAC (Antibiotic-Associated Colitis).

C. difficile is an anaerobic gram-positive, spore-forming rod.

This organism is found as normal fecal flora in 3% of healthy persons.

It is an increasing problem in nursing homes and long-term care facilities.
It is estimated that 10-30% of hospitalized individuals are colonized by C. difficile, plus 60-70% of newborns.
The disease is characterized by bloody diarrhea which often progresses to inflammation of the mucosa and the formation of a pseudomembrane and micro abscesses.

The pathology of the disease is the result of both toxin A (enterotoxin) and toxin B (cytotoxin).
Diarrhea may occur less than one week following acquisition of C. difficile.
The patient may be asymptomatic until exposed to antimicrobials.

Pseudomembraneous Colitis is believed to result from an inflammatory reaction of the bowel wall totoxins produced by C. difficile.

C. difficile may be newly acquired or may represent endogenous overgrowth following disruption of the normal flora, usually by antibiotic therapy.
The pseudomembrane results from a mixture of inflammatory cells, fibrin, bacterial and cellular components, which are released from the bowel mucosa.

C. difficile has been isolated from the hands of health care workers caring for patients colonized with the bacterium.
The endospores can survive on fomites and surfaces for several months.
Since common disinfectants used for daily cleaning are not sporicidal (capable of killing endospores), the endospores survive the cleaning process and are found in high numbers in the rooms of patients colonized or infected with C. difficile.
This organism can contaminate feeding tubes, catheters, and instruments used by such patients.
Because of this, health care workers are supposed to employ Contact Precautions, along with all Standard Precautions, around such patients.
Since episodes of AAC are triggered by a particular antibiotic that was being used by the patient in therapy, it requires permanent discontinuation of the offending antibiotic along with supportive therapy.

Commonly implicated antibiotics include clindamycin, ampicillin and other penicillins, and third-generation cephalosporins.

Further antibiotic therapy is considered unnecessary in patients with only mild symptoms. The diarrhea usually clears up in 7 to 10 days.
When needed, the antibiotics most frequently used for treatment are vancomycin, metronidazole, bacitracin, and rifampin.
There are no vaccines or antitoxins available.

Tetanus:

Clostridium tetani is responsible for the disease Tetanus.
The bacterial endospore gains entry through cuts, scrapes, injury, and wounds. Once inside the body, the spores germinate.
C. tetani produces a powerful neurotoxin (tetanospasmin) which is absorbed into peripheral axons and carried to target neurons in the spinal column.
The toxin attaches to junctions of regulatory neurons. Muscles receive constant stimulaiton and contract uncontrollably. The result is spastic paralysis.
Symptoms usually appear 3 to 21 days after the injury. Symptoms progress from inability to use the muscles of the neck and jaw (known as lockjaw), to difficulty with respiratory and cardiac function.
There is a vaccination available to prevent tetanus. It consists of a series of four DTaP shots given at 2 months, 4 months, 6 months, and the fourth shot given between 12 - 18 months of age.
A DTaP booster shot is to be given between 4 - 6 years of age.
A Td shot is given at 11-12 years.
From that point on, Td boosters are recommended every 10 years.
However, if a person has a severe injury where tetanal endospores are suspected to have contaminated the wound, then a booster shot will be given even sooner.

The person would be administered a combination shot containing the Td booster along with TIG, tetanus immunoglobulin.
TIG provides immediate, short-term protection until the person's immune system can form a protective titer of antibodies against tetanus.

Antitoxins may also be administered to the patient as a preventative measure.

Tuberculosis:

Causative Agents:

Mycobacterium tuberculosis and Mycobacterium bovis.
M. tuberculosis affects humans while M. bovis affects cattle and deer (but can be accidentally transmitted to humans).
M. tuberculosis are non-motile, gram positive, acid-fast bacilli (AFB).
M. tuberculosis are obligate aerobes, which grow well in the oxygen-rich upper lobes of the lungs.
M. tuberculosis are slow growing, with a generation time of about 12-20 hours.

Modified Cell Walls of Mycobacterium tuberculosis:

Mycobacteria have Gram positive cell walls with "extra" cell wall components.
They have mycolic acid, which is thick & waxy, within their cell wall. It is also known as the cord factor.
Mycolic acid (cord factor) allows the bacterium to resist chemicals and dyes, plus contributes to the pathogenicity of the bacterium.
On a Gram stain, mycobacteria form an arrangement known as the palisade arrangement.

The bacteria lie in close parallel rows.
They may lie in “L” and “Y” shapes.

Besides running a Gram stain, the common staining procedure used to test for mycobacteria is the acid fast stain.
Mycolic acid resists the action of the acid alcohol decolorizer ("holds fast"). The bacteria maintain the primary stain (carbolfuschin) and are fuschia in color.

Symptoms:

Those with the disease suffer from chills, persistent cough, constant tiredness, loss of appetite, weight loss, blood in sputum and night sweats. Only about 10% of people infected with TB actually develop the disease. Many only suffer a latent infection.

Pathogenesis:

Tuberculosis is an airborne disease spread by coughing and sneezing. The bacilli are less than 5 µm in size; therefore, can remain suspended indefinitely in the air.
Once breathed in, pulmonary macrophages harbor, but cannot destroy, M. tuberculosis.
Delayed-type hypersensitivity results in the formation of large multinucleated giant cells.
Granulomas form when inflammatory cells collect around the giant cells, walling them off. In tuberculosis, these walled-off granulomas are known as tubercles. The bacteria remain alive, slowly growing within the tubercle.
Caseous necrosis results from release of macrophage enzymes within the tubercle, destroying surrounding tissue.
If the process involves a bronchus, dead material discharges into airways, causing a large lung defect called a lung cavity.Lung cavities spread the bacteria to other parts of the lung. They persist, slowly enlarging for months or years, and shredding tubercle bacilli into the bronchi.

Reactivation TB:

Whenever living organisms persist within a tubercle of a patient, they can resume growing if the person's immunity becomes impaired.
This can happens years after the initial exposure and treatment of TB.
The disease resulting from the renewed growth is called reactivation tuberculosis.
This is common in AIDs patients, or patients with other immunocompromised diseases, who have had TB in the past.

Disseminated (or extra-pulmonary)Tuberculosis:

Sometimes the TB infection is not contained within the lungs, but makes its way through the bloodstream to other organs of the body.
Sometimes the bacterium enters through a cut or sore. In this case, it begins directly as extra-pulmonary (disseminated) TB.

This is a problem for farmers and builders, in areas of the country where the bacterium can be found in the soil.

Epidemiology:

There are approximately 20-25 million cases worldwide. Infection rates are highest among non-whites and elderly poor people. Transmission is almost entirely airborne. 10 or fewer inhaled organisms are enough to cause infection. People with HIV or a weak immune system, or babies and young.

Prediagnosis Transmission of Tuberculosis:

The patient is infective and spreading the TB bacilli through the air from the minute they show up at the doctor's office or hospital. If a health care worker determines the possibility of TB, the patient is to be immediately moved into isolation and Airborne Precautions must be employed. Sputum collection must be done using Airborne Precautions.

Treatment:

Standard treatment of active TB consists of a 6-month regimen:

2 months with Rifater. It contains isoniazid (INH), rifampin (RMP), and pyrazinamide (PZA).
4 months with Rifamate or Rimactane These contain isoniazid (INH) and rifampin (RMP).

Ethambutol (EMB) or Streptomycin (STM) may be added until drug sensitivity is known.
MDR-TB strains are resistant to one, two, or more of these drugs; therefore, are almost impossible to treat.

Mantoux or PPD Test:

The tuberculin skin test is also known as PPD or Mantoux test. This test is used to determine TB status in the US. Healthcare workers (and other workers who deal with the public) are required to have an annual PPD test.
People who are infected with M. tuberculosis develop redness and a firm swelling (induration) within 48-72 hours at the injection site, a manifestation of delayed hypersensitivity to the tubercle bacillus.A strongly positive reaction to the test generally indicates that living M tuberculosis bacilli are present somewhere in the body.
The test is done by injecting PPD (purified protein derivative) into the dermis. A small raised bump (bleb) develops under the skin.

Negative reaction: The bleb is 0-5 mm in diameter.
Indeterminate reaction: The bleb is 5 - 9 mm
Positive reaction: The bleb is greater than 10 mm in diameter.

A positive PPD test result does not distinguish between present infection, past infection, or if the person simply had the BCG vaccine sometime in the past.

It’s important to take a good patient history, to determine which of these may be the case.

If a positive reaction occurs, a sputum culture and chest xray would be ordered.

Why the BCG vaccine for TB is not routinely used in United States:

Vaccination against tuberculosis has been widely used in many parts of the world with varying success. The vaccinating agent, known as Bacille Calmette-Guerin, or BCG, is derived from M. bovis. Use of this vaccination is discouraged in the US, because people who receive the vaccine usually develop a positive PPD test. Since the PPD test is our major TB screening tool in the US, use of the vaccine would conflict.

Airborne Precautions must be employed with TB:

Monitored negative air pressure in relation to surrounding areas. 6 to 12 air changes per hour. Appropriate high-efficiency (HEPA) filtration of room air before discharge of air outdoors or before the air is circulated to other areas in the hospital. Keep the room door closed and the patient in the room. When a private room is not available, place the patient in a room (cohort) with a patient who has active infection with same microorganism, but with no other infection.
For disinfection, an intermediate level disinfectant must be used that is registered as a tuberculocide by the EPA.
All healthcare workers and visitors must use N95 or HEPA filter masks.
If transport or movement is necessary, minimize patient dispersal of droplet nuclei by placing a surgical mask on the patient, if possible.
Airborne Precautions must be employed until the patient is on effective therapy, is improving clinically, and has 3 consecutive sputum cultures, collected on different days, come back negative for AFB.

MOTT (Mycobacterium other than M. tuberculosis) infection:

Individuals with impaired defenses (impaired cell-mediated immunity) are at risk, especially AIDs patients. These infections are either pulmonary or disseminated.
Usually are caused by the species Mycobacterium avium intracellulare, also known as MAC Disease.

MAC Disease (Mycobacterium avium Complex Disease):

Individuals with impaired defenses (impaired cell-mediated immunity) are at risk, especially AIDs patients. These infections are either pulmonary or disseminated.
Usually are caused by the species Mycobacterium avium and Mycobacterium intracellulare.
Also known as MOTT infection (Mycobacterium other than M. tuberculosis) infection. Also sometimes called MAI, which stands for Mycobacterium avium intracellulare.
Organisms belonging to the Mycobacterium avium complex (MAC) are everywhere in the environment and have been isolated from a number of sources around the world.
MAC bacteria were found in the blood of 43% of people within two years of diagnosis with AIDS.
These bacteria are found in water, dust, soil and bird droppings.They enter the body in food and water or sometimes through the lungs. The organisms are found in most sources of drinking water, including treated water systems.

Symptoms:

Weight loss, fever, chills, night sweats, swollen glands, abdominal pains, diarrhea and overall weakness.In the immocompromised person, fever is the main symptom.
MAC affects the intestines and inner organs first, causing liver tests to be high. Swelling and inflammation also occur.

Treatment:

Drugs used to reduce risk of MAC infection include Clarithromycin, Azithromycin, and Rifabutin.
The U.S. Public Health Task Force recommends treatment of disseminated MAC should include at least 2 drugs, one of which should be Clarithromycin or Azithromycin. Treatment should continue for life.
Rifabutin (Mycobutin) can cut in half the rate at which people develop MAC. Taking the drug for prevention of MAC reduced risk of dying by 14%.

Prevention:

It is difficult to avoid contact with MAC bacteria, but there are some ways to reduce the risk.
Boil drinking water. MAC bacteria are found in most water systems, hospital water supplies and bottled water.
Do not eat raw foods, especially salads, root vegetables, and unpasteurized milk and cheese.
MAC bacteria are killed at 176°F, so they are destroyed during normal cooking.
Rinse and peel fruit and vegetables thoroughly.
Avoid contact with animals, especially birds and bird droppings.

Multi-drug Resistant Gram Positive Cocci:

Colonization means that the organism is present in or on the body but is not causing illness. Infection means that the organism is present and is causing illness.
The common Gram positive multi-drug resistant cocci are:

MRSA - Drug-resistant forms of Staphylococcus aureus, including both HA-MRSA and CA-MRSA
VISA & VRSA - Vancomycin-intermediate Staphylococcus aureus and Vancomycin-resistant Staphyloccus aureus
DRSP - Drug-resistant forms of Streptococcus pneumoniae
VRE - Vancomycin-resistant Enterococcus faecalis and Enterococcus faecium
CoNS - Drug-resistant Coagulase-Negative Staphylococci, including S. epidermidis, S. haemolytica & S. hominis

Hospital-Acquired MRSA (HA-MRSA):

The most important reservoirs of MRSA are infected or colonized patients.
Hospital personnel can serve as reservoirs for MRSA and may harbor the organism for many months.
Hospital personnel have been more commonly identified as a link for transmission between colonized or infected patients.
The main mode of transmission of MRSA is via hands (especially health care workers' hands) which may become contaminated by contact with:

Colonized or infected patients.
Colonized or infected body sites of the personnel themselves.
Devices, items, or environmental surfaces contaminated with body fluids containing MRSA.

Community-Acquired MRSA (CA-MRSA):

Humans are a natural reservoir for S. aureus.
Asymptomatic colonization is far more common than infection.
Colonization occurs in the nasopharynx, perineum, or skin:

If the cutaneous barrier has been disrupted or damaged
May occur shortly after birth and may recur anytime thereafter.

Family members of a colonized infant may also become colonized.
Transmission occurs by direct contact with a colonized carrier.
Carriage rates (i.e. colonized carriers) are 25% to 50%.
Carriage rates higher than in the general population are observed in:

Injection drug users
Persons with insulin-dependent diabetes
Patients with dermatologic conditions
Patients with long-term indwelling intravascular catheters
Health-care workers

Young children tend to have higher colonization rates, probably because of their frequent contact with respiratory secretions.
Colonization may be transient or persistent and can last for years.
Becoming an increasing problem in sports and gyms.

VISA and VRSA:

Vancomycin-intermediate Staphylococcus aureus (VISA) are not susceptible to vancomycin.

Therefore, vancomycin treatment is not reliable for treating these infections.
However, to date, all VISA isolates have been susceptible to other FDA-approved antimicrobial drugs.

Vancomycin-resistant Staphyloccus aureus (VRSA) are resistant to vancomycin.

These organisms have not yet been found in nature but might emerge from VISA.
Vancomycin would not be effective at all for treating these infections.

DRSP:

Drug Resistant Streptococcus pneumoniae are resistant to one or more commonly used antibiotics.
Seven sero-types (6A, 6B, 9V, 14, 19A, 19F, and 23F) account for most DRSP. Since 1987, the incidence of DRSP has increased in the United States.
Of the S. pneumoniae infections that occur, up to 40% are caused by DRSP.

The totals for S. pneumoniae infections each year include100,000-135,000 hospitalizations for pneumonia, 6 million cases of otitis media, and over 60,000 cases of invasive disease, including 3300 cases of meningitis.
Death occurs in 14% of hospitalized adults with invasive disease.

VRE:

Since 1989, a rapid increase in the incidence of infection and colonization with Vancomycin-Resistant Enterococci (VRE) has been reported from U.S. hospitals.
This increase poses two major problems:

The lack of available antimicrobials for treatment of infections caused by VRE, because most VRE are also resistant to multiple other drugs.
The possibility that the vancomycin-resistance genes present may be transferred to other Gram-positive microorganisms such as Staphylococcus aureus.

CoNS:

Central venous catheters are the instrument associated with most hospital-acquired bloodstream infections, with the most common causative agent being Coagulase-Negative Staphylococcus epidermidis.
The mortality rate among infected patients is estimated at 35%.

Gram Positive Bacterial Diseases:

There are 21 Gram positive bacterial diseases we will concentrate on in this course.These diseases were assigned as part of a group activity. You should receive information on these diseases from your classmates.
For each disease you will summarize the following: 1) name of disease, 2) causative agent(s), 3) Description of the causative agent(s), 4) symptoms, 5) incubation period, 6) pathogenesis, 7) epidemiology, 8) treatment (Note: Be specific!), 9) prevention, 10) control, 11) isolation precautions employed in a healthcare setting for the disease (including information contained in Appendix A footnotes), and 12) any additional information requested as a “Note.”
If your disease includes a "Note" about something you must include in your summary, then you must include it! Throughout the semester many diseases will have these notes. “Notes” are meant to help guide you so that you're covering all the pertinent information. "Notes" are a required part of the exam essays!
- The information in the “note” is meant to be discussed within the report itself, not as an addition at the bottom of the report.
- For example, if I say to discuss something about the pathogenesis of your disease, do it in the “Pathogenesis” section, not as a “note” at the bottom of the report.

Scalded Skin Syndrome (also known as Ritter's Disease) - pages 538-9

Note: Under Pathogenesis, include discussion of the two exotoxins produced by the bacterium. Under Epidemiology, include discussion of mortality rates and their causes among infants and adults, identifying susceptible adults. Under Prevention & Control, include discussion of how healthy workers can bring the toxic strain into the hospital nursery, and how workers would be tested and treated if there was an outbreak. Include current treatments from the web link, not the textbook. (All information available at the above web link.)

Toxic Shock Syndrome (TSS) - pages 641-2

Note: TSS has both menstrual and non-menstrual causes. When TSS results from the use of tampons, that is the menstrual cause. When TSS is caused by the use of intravaginal contraceptive devices, or as a complication of skin abscesses, surgery, or burns, those are the non-menstrual causes. Explain these forms in the report. Be certain to equally discuss these menstrual and non-menstrual forms of TSS under Pathogenesis, Epidemiology, Prevention, and Control. Also, under Pathogenesis, be certain to name the toxins produced in TSS. Note: Use pages 474-5 of the textbook to explain what superantigens are, including the increase of T-cell response that occurs. This information is part of the pathogenesis of TSS.

Staphylococcal Wound Infections, caused by both Staphylococcus aureus and Staphylococcus epidermidis - pages 693-6

Note: The infection is caused by two different species of staphylococci. You must distinguish between Staphylococcus aureus and Staphylococcus epidermidis under Description of Causative Agents, Symptoms, Pathogenesis, Epidemiology, Treatment, Prevention, Control, and Isolation Precautions. Here, as an example, is how you should answer Isolation Precautions:
- Major wounds require Contact Precautions for the duration of the illness and are usually caused by Staphylococcus aureus.
- Minor wounds require Standard Precautions and are usually caused by Staphylococcus epidermidis.

Subacute Bacterial Endocarditis (SBE) - pages 718-9

Note: Discuss link to dental and surgical procedures.

Streptococcal Pyoderma, including Impetigo - pages 539-41

Note: Distinguish between streptococcal pyoderma and impetigo. Do not include any information about staphylococci, as this is on streptococcal pyoderma.

Streptococcal Pharyngitis (also known as Strep Throat) - pages 565-9

Note: Under Pathogenesis, discuss the effects of the various virulence factors of Streptococcus pyogenes: C5a peptidase, hyaluronic acid capsule, M protein, Protein F, Protein G, SPEs, Streptolysins O & S, and tissue degrading enzymes. Discuss these complications of strep throat: scarlet fever and rheumatic fever.

Necrotizing Fasciitis (also known as Streptococcal Gangrene or Flesh-Eating Disease) - page 696
Streptococcal Toxic Shock Syndrome (STSS) - page 696

Note: Use pages 474-5 of the textbook to explain what superantigens are, including the increase of T-cell response that occurs.

Streptococcal Pneumonia (also known as Pneumococcal Pneumonia) - pages 576-9

Note: You must discuss the vaccination schedules (number of shots, when given and to whom) for PCV7 and PPV23. Also, use the second link to discuss DRSP: what it is, serotypes involved, where outbreaks usually occur, and what’s helping to control the problem.

Dental Caries, leading to Periodontal Disease & Acute Necrotizing Ulcerative Gingivitis (ANUG, known as Trench Mouth or Vincent's Disease) - p. 602-3

Note: Distinguish between dental caries, periodontal disease, and ANUG. Explain when/how each develops, the bacteria involved, and the treatments for each.

Neonatal Sepsis, Early or Late Onset (also known as Group B Streptococcal Disease (GBS) - page 666

Note: Distinguish between Early and Late Onset of Neonatal Sepsis as to transmission, symptoms and treatment.

Diphtheria - pages 568-71

Note: You must distinguish between cutaneous and pharyngeal (respiratory) diphtheria with regard to symptoms and isolation precautions employed. You must discuss the diphtheria vaccination schedule (number of shots & when given) for children, adolescents, and adults. Distinguish between when DTaP is used and Td is used.

Anthrax - pages 283, 503 & 577

Note: Discuss the three forms of anthrax (respiratory, cutaneous, and gastrointestinal), including how each is transmitted, its symptoms, and treatment. Discuss the use of anthrax in bioterrorism.

Listeriosis - pages 668-71

Note: Discuss the problems of Listeriosis related to pregnancy.

Actinomycosis (or Lumpy Jaw) - pages 704-5;

Discuss relationship to dental and oral surgery.

Foodborne Botulism - pages 672-4 & 812;
Clostridial Myonecrosis (or Gas Gangrene)- pages 701-3;
Pseudomembraneous Colitis (or Clostridium difficile Colitis or Antibiotic-Associated Colitis) - pages 461, 510-11 & 601;
Tetanus (or Lockjaw) - pages 698-701;

Note: Give the name of the neurotoxin. Discuss the tetanus vaccination schedule (number of shots & when given) for children, adolescents, and adults. Distinguish between when DTaP is used and Td is used. Also, be certain to discuss when TIG is used.

Tuberculosis - pages 580-4;

Note: Besides the 10 required topics to be covered, also do the following. Explain what happens to the mycobacteria inside the pulmonary macrophages. After about two weeks, a delayed-type hypersensitivity response occurs. Explain the steps involved in delayed hypersensitivity. Explain the granuloma formation which occurs in tuberculosis and give the specific name for the granulomas formed in tuberculosis. Explain the process of caseous necrosis which occurs in tuberculosis. Explain the formation of lung cavities in tuberculosis. Explain what reactivation tuberculosis is and how it can develop. Describe the tuberculin skin test (also known as the Mantoux test) and how to interpret its results.Give the measurements for negative, indeterminate, and positive reactions. Explain who is at risk for infection by MOTT, what kind of infections occur with MOTT and name the most common of the MOTT species to cause infection. Describe patient placement, room standards for TB patients, and respiratory protection required for healthcare workers working with TB patients. Describe MDR-TB and discuss its impact. Describe "prediagnosis transmission of tuberculosis" and discuss its impact. Describe the level of disinfection required with tuberculosis.

Mycobacterium avium Complex Disease (MAC Disease) - pages 759-80;

Note: Besides the 10 required topics to be covered, also do the following. Give the names of the two closely related species comprising MAC. Explain how MAC disease progresses in the immunocompromised, such as an AIDS patient. Explain what drug is used with HIV patients in an effort to prevent MAC disease. Explain how MAC disease is treated in an AIDS patient.

From assignment, Gram Negative and Miscellaneous Bacteria:

Aerobic Gram Negative Bacilli - Pseudomonas, Legionella, and Bordetella:

Pseudomonas:

The genus-species name for the most common species of Pseudomonas associated with human infections is Pseudomonas aeruginosa.
Pseudomonas is an opportunistic pathogen. It seeks out patients who have suffered sever trauma, such as burns or wounds; patients who are immunosuppressed, such as AIDS, MS, CF, and cancer patients; and patients who must catheterize on a daily basis or who have indwelling catheters.
Community-acquired infections attributed to Pseudomonas aeruginosa include:

Skin rashes from contaminated swimming pools and hot tubs.
Eye infections from contaminated contact lens solution.
Foot infections from nails.
Heart valve infections in drug users.
Ear infections in swimmers.
Lung infections in CF patients.

The types of nosocomial (hospital-acquired) infections attributed to Pseudomonas aeruginosa include:

Wound infections.
Lung infections.
UTIs.
Skin infections in burn patients.

Pseudomonas aeruginosa is found in soil, in water, and on plants (including fruits & vegetables).
Pseudomonas aeruginosa can contaminate almost any watery source:

Soaps & ointments.
Eyedrops & contact lens solutions.
Cosmetics.
Disinfectants and infectable drugs.
Swimming pools and hot tubs.

Pseudomonas aeruginosa can enter the hospital environment on the soles of shoes, flowers & plants, and fruits & vegetables.
Bioremediation:

Bioremediation is the process that uses microorganisms to degrade harmful chemicals.
The first microorganism patented for bioremediation and its use was Pseudomonas cepacia.

Legionella:

The genus-species name for the most common species of Legionella associated with human infections is Legionella pneumophila , a motile, rod-shaped Gram-negative bacterium.
Infection develops from breathing aerosolized water which has been contaminated with Legionella pneumophila , such as found in air conditioning systems, heating towers, and plumbing.
Legionella pneumophila is resistant to chlorine, allowing it so survive in these watery environments.
Symptoms include muscle aches, headache, fever, cough, shortness of breath, chest pain, and diarrhea.
Healthy persons will experience flu-like symptoms, while those at risk will develop pneumonia and multi-system failure.
Smokers, persons with breathing disorders, immunocompromised patients, the elderly and alcoholics are most at risk.
Legionella pneumophila multiplies within phagocytes; death of these and other cells is followed by sloughing of the cells lining the alveoli, tissue necrosis, and formation of microabscesses within the lungs.
Regular cleaning and disinfection of humidifying devices is necessary.

Bordetella:

The genus-species names for the most common species of Bordetella associated with human infections.
The habitat and mode of transmission for the human species of Bordetella .
The two types of vaccines developed against Bordetella.
Transmission of whooping cough, effects on children, and the main cause of outbreaks.
The types of infections experienced by adults that allow them to serve unknowingly as reservoirs of whooping cough.

The characteristics and consequences of wound infections caused by:

Staphylococcus aureus:

Gram-positive cocci arranged in clusters that are facultative (grow aerobically and anaerobically).
Symptoms include production of pus, swelling, redness, and pain. If the infection is extensive, or has entered the blood stream, fever is present. Some strains of S. aureus can produce toxic-shock syndrome, somtimes accompanied by rash and diarrhea. S. epidermidis infections are usually minor.
It is likely that multiple virulence factors act together to produce a wound infection. Clumping factor, coagulase, and protein A coat the organisms and disguise them from phagocytic attack. Released protein A reacts with immunoglobulin and contributes to inflammation and acucumulation of pus.
Most wound infections are due to the patient’s own Stahylococcus strain. Advanced age, poor general health, immunosuppression, prolonged pre-op hospital stay, and infection at a site (other than the site of surgery) increase infection risk.
Treatment is problematic because of developed antibiotic resistance. New antibiotic use is also problematic, but Vancomycin is generally effective against MRSAs. The most important reservoirs of MRSA are infected or colonized patients.

Hospital personnel can serve as reservoirs for MRSA and may harbor the organism for many months.
Hospital personnel have been more commonly identified as a link for transmission between colonized or infected patients.
The main mode of transmission of MRSA is via hands (especially health care workers' hands) which may become contaminated by contact with:

Colonized or infected patients.
Colonized or infected body sites of the personnel themselves.
Devices, items, or environmental surfaces contaminated with body fluids containing MRSA.

Vancomycin-Intermediate Staphylococcus aureus (VISA) are not susceptible to vancomycin.

Therefore, vancomycin treatment is not reliable for treating these infections.
However, to date, all VISA isolates have been susceptible to other FDA-approved antimicrobial drugs.

Vancomycin-resistant Staphyloccus aureus (VRSA) are resistant to vancomycin.

These organisms have not yet been found in nature but might emerge from VISA.
Vancomycin would not be effective at all for treating these infections.

Cleansing and removal of dirt and devitalized tissue from accidental wounds minimizes infection, as does prompt suturing. Infection rate is actually increased if meds are given more than 3 hours before or 2 hours after surgery.
For major wounds caused by Staphylococcus aureus use Standard and Contact precautions for the duration of the illness.

Staphylococcus epidermidis:

Gram-positive cocci arranged in clusters that are facultative (grow aerobically and anaerobically).
Symptoms include production of pus, swelling, redness, and pain. If the infection is extensive, or has entered the blood stream, fever is present. S. epidermidis infections are usually minor.
Immunocompromised patients can be subject to subacute bacterial endocarditis or multiple tissue abscesses caused by organisms living in plastic catheters that come loose and are carried to the bloodstream.
Most wound infections are due to the patient’s own Stahylococcus strain. Advanced age, poor general health, immunosuppression, prolonged pre-op hospital stay, and infection at a site (other than the site of surgery) increase infection risk.
Treatment is problematic because of CoNS antibiotic resistance. Central venous catheters are the instrument associated with most hospital-acquired bloodstream infections. The the mortality rate among infected patients is estimated at 35%.
Cleansing and removal of dirt and devitalized tissue from accidental wounds minimizes infection, as does prompt suturing. Infection rate is actually increased if meds are given more than 3 hours before or 2 hours after surgery.
For minor wounds caused by Staphylococcus epidermidis use Standard precautions.

Streptococcus pyogenes (Group A strep):

Gram-positive coccus. An especially virulent strain due to pyrogenic exotoxin A (causes streptococcal toxic shock) and exotoxin B (destroys tissue by breaking down protein).
Symptoms include acute pain development at surgical wound site or trauma site. Swelling, fever, and confusion quickly develop. Overlying skin is tense and discolored. Without prompt treatment, shock and death follow in a short time.
Streptococcus pyogenes multiplies in the wound, releasing enzymes and toxins. Subcutaneous fascia and fatty tissue are destroyed (necrotizing fasciitis). The toxins enter the bloodstream.
10-20 cases occur per 100,000. Associated with injected drug abuse, diabetes, liposuction, hysterectomy, and bunion surgery, but most occur with minor injuries.
There are no proven preventative measures. Urgent surgery to release pressure and remove dead tissue, sometimes including amputation. Penicillin works with early infection, but has no effect on organisms in necrotic tissue and no effect on toxins.
Use Standard and Contact precautions as needed.

Pseudomonas aeruginosa:

Motile gram-negative bacterium with a single flagellum.
Symptoms include the tissue turning a green color. The patient may experience chills, fever, and shock.
Produces tissue damage, prevents healing, and increses the risk of septic shock.
Pseudomonas aeruginosa is introduced into the hospital by shoes, produce, ornamental flowers, and plants. Pseudomonas aeruginosa can live in some soaps and disinfectants.
Elimination of potential sources of the bacterium and prompt care of burns and wounds.
Use of sterile technique while performing burn and wound care. Antibiotics such as carbenicillin, ticarcillin, gentamicin, and tobramycin.
Standard and Contact Precautions.

Facultative Anaerobic Gram Negative Bacilli - Enterobacteriaceae family, Vibrionaceae family, Pasteurellaceae family, and Spirilliaceae family:

The family of Enterobacteriaceae:

The family of Enterobacteriaceae includes E. coli, Salmonella, Shigella, Serratia, Citrobacter, Klebsiella, Enterobacter, Providencia, and Morganella. Your study concentrated on just E. coli, Salmonella, and Shigella.
The three major groups of antigens used to serotype the family.
The most common mode of transmission of the family of Enterobacteriaceae.
How nosocomial infections of the family of Enterobacteriaceae commonly occur.
The two types of mechanisms that lead to diarrheal disease by the family of Enterobacteriaceae.
Why women are more susceptible to UTIs, the most common cause of UTIs, and the percentage of infection involved.

Gram-Negative Septicemia:

The % of septicemia cases that are caused by Gram negative bacteria.
The symptoms of septicemia.
Three common Gram negative bacteria which cause septicemia.
When/how endotoxins are released.
How complement activation can lead to lung tissue damage in Gram-Negative Septicemia.
How clotting activation can lead to hemorrhage.
How macrophage activation can lead to shock and impaired oxygen exchange.
What TNF is and how it is harmful.
What IL-1 is and how it is harmful.

E. coli O157:H7:

How E. coli O157:H7 is spread.
What illness E.coli O157:H7 causes.
How E. coli O157:H7 infection is diagnosed.
How the illness is treated.
What can be done to prevent E. coli O157:H7 infection.
Describe HUS:

The percentage of E. coli O157:H7 infection leading to HUS.
How HUS is treated.
The percentage of HUS leading to death.
The long term consequences of HUS.

ESBLs (Extended Spectrum Beta-Lactamases):

Know what they are and why its important that we test for their presence.
Name types of Gram negative bacteria that produce ESBLs.

Salmonella:

Salmonella is not part of the normal flora of the GI tracts of humans.
The two serotypes of Salmonella causing most human infection.
Typhoid fever transmitted from human strains of Salmonella.
The type of diarrhea caused by Salmonella.
What must be done to rid carriers of infection.
Describe Salmonellosis.

The types of pets from which children can get salmonellosis.
The most common foods from which people get salmonellosis.
The types of people at greatest risk from infection.

Shigella:

Shigella is not part of the normal flora of the GI tracts of humans.
How Shigella can cause disease in humans.
The type of diarrhea caused by Shigella.
Describe Shigellosis, also known as Bacillary Dysentery.

The Vibrionaceae family has one main genus, Vibrio:

Vibrio:

The genus-species name for the most common species of Vibrio associated with human infections.
The range of diseases of Vibrio cholera.

The Pasteurellaceae family includes two genera, Haemophilus and Pasteruella:

Haemophilus influenzae Type B:

The various diseases that can result from infection by Haemophilus influenzae Type B.
Why diseases of Haemophilus influenzae Type B in small children are now being controlled.

Pasteruella:

How most human infections involving Pasteruella occur.
How Pasteruella infection can spread in immunocompromised people

The Spirilliaceae family includes two genera, Campylobacter & Helicobacter:

Campylobacter:

The genus-species name for the most common species of Campylobacter associated with human infections.
What % of poultry are considered to carry the bacterium in large enough doses to be infective.
Campylobacteriosis is the leading cause of bacterial diarrheal infection in the US.
How watery diarrhea develops from a Campylobacter infection.

Helicobacter:

Ulcers associated with Helicobacter pylori:

What causes ulcers.
What the symptoms of an ulcer are.
The tests used for diagnosis of ulcers.
The treatment.

Anaerobic Gram Negative Bacilli - Bacteroides fragilis and Other AGNB (Anaerobic Gram Negative Bacteria):

Most commonly cause intra-abdominal, genital, and pleuropulmonary infections.
Bacteroides species are anaerobic bacteria that are predominant components of the bacterial flora of mucous membranes and, therefore, are a common cause of endogenous infections.
Bacteroides infections can occur in all body sites, including the central nervous system, the head, the neck, the chest, the abdomen, the pelvis, the skin, and the soft tissues.
Anaerobic infections can cause systemic infections with chills, vomiting, and headache.
Aspiration of gastric flora can lead to pulmonary infection resulting in cough, breathing difficulty temperature over 100 degrees.
Wounds or ruptures of the intestinal tract can seed the organism into adjacent tissues and cavities causing bloody diarrhea and abdominal pain.
The exact frequency of AGNB infection is difficult to calculate because of inappropriate methods of collection, transportation, and cultivation of specimens.
AGNB are more commonly found in chronic infections. Their rate of recovery in blood cultures is 2-5% and is higher in association with patients that have any predisposing conditions.
Bacteroides fragilis has a capsule while other Bacteroides do not. As with other encapsulated organisms, this virulence factor is antiphagocytic and helps to promote abscess formation.
Anaerobic infections can cause blood stream invasion which can seed the organisms in any organ or tissue. Aspiration of gastric flora can lead to pulmonary infection. Wounds or ruptures of the intestinal tract can seed the organism into adjacent tissues and cavities.
The patient's recovery from anaerobic infection depends on prompt and proper management according to the following 3 principles:
Neutralizing toxins produced by anaerobes.
Preventing bacterial local proliferation by changing the environment. The environment is controlled by debriding necrotic tissue, draining pus, improving circulation, alleviating obstruction, and increasing tissue oxygenation.
Limiting the spread of bacteria. In many cases, antimicrobial therapy is the only form of therapy required, but it can also be an adjunct to a surgical approach.
Where AGNB and other anaerobes predominate, aggressive treatment of acute infection can prevent chronic infections. When the risk of anaerobic infections (eg, intra-abdominal and wound infection following surgery) is high, proper antimicrobial prophylaxis may reduce the risk.
Preventing oral flora aspiration by improving neurologic status, suctioning oral secretions, improving oral hygiene, and maintaining lower stomach pH can reduce the risk of aspiration pneumonia and its complication.

Gram Negative Cocci - The genus Neisseria:

Neisseria:

The habitat, mode of transmission, and diseases associated with Neisseria gonorrhoeae.
The habitat, mode of transmission, and diseases associated with Neisseria meningitidis.
Meningococcal Meningitis:

How meningococcal meningitis is transmitted.
The progression of symptoms.
The factors which contribute to infection.
The vaccine to control meningococcal meningitis and which serotypes it works against.
The current recommendation for college students.

Miscellaneous Bacteria - Chlamydia, Mycoplasma, Treponema & Borrelia:

Chlamydia Sexually Transmitted Disease:
- Causative Agent: Chlamydia trachomatis, a spherical, obligate intracellular bacterium. It lacks a peptidoglycan layer, giving a general gram negative appearance.
- It has two forms to its life cycle:

The reticulate body (RB) exists as a fragile non-infectious form that reproduces by binary fision.
The elementary body (EB) is the dense-appearing infectous form released upon the death and rupture of the hosts cell and causes the most damage.

Symptoms for women:

Abnormal discharge or burning sensation when urinating, lower abdominal pain, lower back pain, nausea, fever, pain during intercourse, bleeding between menstrual periods. Leading cause of pelvic inflammatory disease (PID), infertility, and ectopic pregnancy. Rarely causes arthritis, skin lesions, and inflammation of eye and urethra (Reiter's syndrome).

Symptoms for men:

Discharge from penis or a burning sensation when urinating, burning and itching around opening of penis, pain and swelling in the testicles (but uncommon).Rarely causes sterility.

Chlamydia is known as a “silent” disease because about three quarters of infected women and about half of infected men have no symptoms!!
Pathogenesis:

The elementary body (EB) is the transmittable form. Elemetary body (EB) attaches to specific receptors on epithelial cells-> endocytosis->transforms to reticular body (RB) in vacuole->replication by binary fission and the large number of RBs produced form an inclusion in the cytoplasm of the cell that rings the nucleus.->differentiation into EB-> vacuole ruptures and releases EB (48-72 hours to rupture)->infects adjacent cells.

The infection is transmitted in 2 ways:

From one person to another by close personal contact such as through sexual intercourse (not by casual contact such as a handshake).

From mother to child with passage of the child through the birth canal. Chlamydia can cause pneumonia or serious eye infections in a newborn, especially among children born to infected mothers in developing countries.

If left untreated:

If untreated, chlamydial infections can progress to serious reproductive and other health problems with both short-term and long-term consequences.Like the disease itself, the damage that Chlamydia causes is often “silent.” In women, untreated infection can spread into the uterus or fallopian tubes and cause pelvic inflammatory disease (PID). This happens in up to 40 percent of women with untreated chlamydia. PID can cause permanent damage to the fallopian tubes, uterus, and surrounding tissues. The damage can lead to chronic pelvic pain, infertility, and potentially fatal ectopic pregnancy.

Epidemiology:

The greater the number of multiple sex partners, the greater the risk.Found in sexually active teenage girls and young women.Women whose partners have not been appropriately treated are at high risk for reinfection.5% of all sexually active women are estimated to be infected with Chlamydia.5%-14% of routinely screened females aged 15-19 years are infected with Chlamydia.3%-12% of women aged 20-24 years are infected with Chlamydia.Women infected with Chlamydia are up to 5 times more likely to become infected with HIV.Chlamydia can also be transmitted in a nonsexual way through the use of an uncholrinated swimming pool.

Treatment:

Easily treated and cured by a single dose of azithromycin or a week of doxycycline (twice a day).
All sexual partners should be tested and treated, and should abstain from sexual intercourse until completing the treatment.

Prevention: Screening annually is recommended for women over twenty five.All pregnant women should be tested.The surest way to avoid transmission is to abstain.Being in a long-term monogamous relationship and/or using latex male condoms helps in prevention.Notify all recent sexual partners if diagnosed with infection.

Walking Pneumonia ( also called Primary Atypical Pneumonia):

Causative Agent: Mycoplasma pneumoniae, a small (0.2 µm diameter), pleomorphic bacterium lacking a cell wall. Distinguishing characteristics are slow growth and aerobic metabolism. It's the smallest known free-living microorganism. It has a selective affinity for respiratory epithelial cells.
Symptoms:

The onset of walking pneumonia is typically gradual.The first symptoms are fever, headache, muscle pain, and fatigue. After several days, a dry cough begins, but later mucoid sputum may be produced. 15% of cases have middle ear infections. Rarely requires hospitalization.

Pathogenesis:

It is transmitted by aerosolized droplets of an infected person's respiratory secretions, via coughing, sneezing, spitting, etc..Only a few inhaled organisms are necessary to start an infection.
The organisms attach to specific receptors on the respiratory epithelium, interfere with the ciliary action, and cause the ciliated cells to slough off. An inflammatory response (from infiltration of lymphocytes and macrophages) causes the walls of the bronchial tubes and alveoli to thicken.
Infected persons are often young adults such as college students or military recruits where close contact facilitates person-to-person transfer.
It is the cause of about one-fifth of all bacterial pneumonias.
Immunity after recovery is not permanent, and repeat attacks have occurred within 5 years.

Treatment:

Antibiotics that act against bacterial cell walls, such as the penicillins and cephalosporins, are, of course, not effective.
Tetracycline and erythromycin shorten the illness if given early, but they are bacteriostatic, meaning they only inhibit the growth of the bacteria without killing them.

Prevention:

Avoid crowding in schools, colleges, large institutions and military facilities. If ill, keep your children home from day care and school to stop spread of the disease.
Enforce good infection control measures and good hand washing. People with weakened immune systems need to wear masks to protect from respiratory exposure.
In healthcare, employ Droplet Precautions for the duration of the illness.

Syphilis:

Causative Agent: Treponema pallidum, a slender, motile spirochete with tightly wound coils.
Symptoms:

Primary stage: Chancre at site of infection; lymph nodes enlarge.
Secondary stage:

Rash may appear as rough red, or reddish brown, spots that occur on both the palms of the hands and bottoms of the feet. A different appearance may occur on other parts of the body. The rash may be too faint to recognize or may resemble rashes caused by other diseases.
Aches and pains, mucous membrane lesions and T. pallidum in circulation react with antibodies to form immune complexes.

Latent stage: When the disease lies dormant.
Tertiary stage:

Gummas (a granulomatous necrotizing mass) occurring anywhere in the body. Damage to large blood vessels, eyes, and nervous system. Insanity.

Incubation period:

Primary stage: initial lesion (chancre), 3-4 weeks past inoculation.
Secondary stage: 4-10 weeks past chancre lesion.
Tertiary stage: Could be decades.

Pathogenesis:

Syphilis can be spread by sexual contact to genitalia, mouth, or rectum. Syphilis can reoccur because no permanent immunity occurs after treatment and no vaccine is available.
Primary lesion, or chancre (firm, painless ulcer), appears at site of inoculation, heals after 2 to 6 weeks.
T. pallidum invades the blood vessel system and is carried throughout body, causing fever, rash, mucous membrane lesions.
A person with syphilitic sores has an increased chance of contracting AIDS from an infected partner.

Congenital Syphilis:

Syphilis can cross the placenta and infect a fetus. Damage doesn't occur until around the fourth month of gestation, which means that prompt treatment of the mother can prevent the fetus from contracting.
25% of such pregnancies end in miscarriage or stillbirth. Another 40 to 70%, will result in a baby with congenital syphilis.
If untreated, congenital syphilis will progress to late-stage syphilis and cause serious damage to the brain and organs of the baby.

Treatment:

Primary and Secondary: Penicillin. Patients allergic to penicillin, are given doxycycline, tetracycline, or erythromycin.
Tertiary – Long-term antibiotic therapy. Damage done before therapy is irreversible.

Control:

The best control is education about all STDs to teenagers. Prompt identification of syphilis, treatment of sexual contacts, abstinence during treatment, and consistent use of condoms. Be in a long-term, mutually monogamous relationship with a partner who has been tested and is known to be uninfected.

Lyme Disease:

Causative Agent: Borrelia burgdorferi, a large microaerophilic spirochete.
Symptoms:

Slowly expanding "bull's-eye" rash (called erythema migrans), accompanied by general tiredness, fever, headache, stiff neck, muscle aches, and joint pain.

If untreated:

Weeks to months later, patient develops rheumatoid arthritis, including intermittent episodes of swelling and pain in the large joints.
May develop neurologic abnormalities, such as aseptic meningitis, facial palsy, motor and sensory nerve inflammation (radiculoneuritis), and inflammation of the brain (encephalitis).
Rarely, cardiac problems, such as atrioventricular block, acute inflammation of the tissues surrounding the heart (myopericarditis) or enlarged heart (cardiomegaly).

Pathogenesis:

Lyme Disease is a zoonosis and humans are accidental hosts.
In the United States, ticks of the genus Ixodes serve as the vectors for transmitting the Lyme Disease bacterium, Borrelia burgdorferi, to humans.
Known as the deer tick, or black-legged tick, Ixodes scapularis is responsible for transmitting bacteria to humans in the northeastern and north central U.S..
Tick-to-human transmission of the Lyme disease bacteria usually occurs after approximately 2 or more days of feeding.
Adult ticks can transmit the disease, but since they are larger and more likely to be removed from a person's body within a few hours, they are less likely than nymphs to have sufficient time to transmit the infection.
White tailed deer, the white-footed mouse, other small mammals, and birds of the natural hosts for the ticks.

Two-Year Life cycle of Ixodes scapularis, the principle vector of Borrelia burgdorferi:

First Year:

Spring: Female tick drops from animal host (deer) and lays uninfected eggs.
Summer: Uninfected larvae hatch.
Fall: Uninfected larvae feed on infected animal host (such as white-footed mouse, other small mammals, deer, and birds) and acquire B. burgdorferi, the spirochete that causes Lyme Disease. The infected larvae then become dormant.
Winter: Infected larvae molt, becoming infected nymphs.

Second Year:

Spring: Infected nymphs feed on animal host (such as white-footed mouse, other small mammals, and birds), transmitting B. burgdorferi.

Infected nymphs may feed on humans; most accidental transmission occurs here. Nymphs are smaller and harder to find on a person’s body.

Summer: Infected nymphs molt, becoming infected adult ticks.
Fall: Infected adult ticks feed on animal host (white-tailed deer primarily).

Infected adult ticks may feed on humans; accidental transmission occurs if ticks are not removed from person’s body.

Winter: Ticks mate. Females remain on the animal host (deer) and become dormant. The males die.

Treatment:

Antibiotic treatment for 3-4 weeks with doxycycline or amoxicillin is generally effective in early disease.
Cefuroxime or erythromycin can be used for persons allergic to penicillin or who cannot take tetracyclines.
In later disease, particularly with neurologic manifestations, may require treatment with IV ceftriaxone or penicillin for 4 weeks or more, depending on disease severity.
In later disease, treatment failures may occur and retreatment may be necessary.

Prevention:

As of February 25, 2002, the manufacturer of the LYMErix™ vaccine, announced that it would no longer be commercially available.
Avoid tick habitats. Those at risk for Lyme Disease are outdoor workers or anyone (especially children) who frequent wooded, brushy, and grassy places.
Use personal protection measures such as light colored clothing, long sleeved shirts and tucking pants into socks.
The risk of tick attachment can be reduced by applying insect repellents containing DEET (n,n-diethyl-m toluamide) to clothes and exposed skin, and applying Permethrin (which kills ticks on contact) to clothes.
Daily checks for ticks:

Prompt removal of any attached tick will help prevent infection.
Embedded ticks should be removed using fine-tipped tweezers. DO NOT use petroleum jelly, a hot match, nail polish, or other products.
Grasp the tick firmly and as closely to the skin as possible.
With a steady motion, pull the tick's body away from the skin.
The tick's mouthparts may remain in the skin, but do not be alarmed. The bacteria that cause Lyme disease are contained in the tick's midgut or salivary glands.
Cleanse the area with an antiseptic.

Control:

Taking preventive antibiotics after a tick bite.
Remove leaf litter, brush, and wood piles around houses and at the edges of yards.
Clear trees and brush to admit more sunlight and reduce the amount of suitable habitat for deer, rodents, and ticks.
Early diagnosis and prompt antibiotic treatment are important strategies to avoid the costs and complications of late-stage disease.

Gram Negative & Miscellaneous Bacterial Diseases:

There are 20 Gram negative and miscellaneous bacterial diseases which will concentrate on in this course. These diseases have been assigned as part of a group activity. You should receive information on these diseases from your classmates.
For each disease you will summarize the following: 1) name of disease, 2) causative agent(s), 3) Description of the causative agent(s), 4) symptoms, 5) incubation period, 6) pathogenesis, 7) epidemiology, 8) treatment (Note: Be specific!), 9) prevention, 10) control, 11) isolation precautions employed in a healthcare setting for the disease (including information contained in Appendix A footnotes), and 12) any additional information requested as a “Note.”
If your disease includes a "Note" about something you must include in your summary, then you must include it! Throughout the semester many diseases will have these notes. “Notes” are meant to help guide you so that you're covering all the pertinent information. "Notes" are a required part of the exam essays!
- The information in the “note” is meant to be discussed within the report itself, not as an addition at the bottom of the report.
- For example, if I say to discuss something about the pathogenesis of your disease, do it in the “Pathogenesis” section, not as a “note” at the bottom of the report.

Pseudomonas aeruginosa Burn infections, UTI's, Pneumonia, and other nosocomial infections - pages 697-8;
Legionnaire's Disease - pages 571-3;
Pertussis (or Whooping Cough) - pages 566-9;

Note: Discuss the pertussis vaccination schedule (number of shots & when given) for children.

E. coli Infections - pages 603-4;

NOTE: Include discussion of ETEC (Enterotoxigenic E. coli), EIEC (Enteroinvasive E. coli), EPEC (Enteropathogenic E. coli), EHEC (Enterohemorrhagic E. coli, E. coli O157:H7, and HUS in your answer.

Salmonellosis & Typhoid Fever - pages 604-6;

NOTE: Include discussion of the difference between Salmonellosis & Typhoid Fever in your answer.

Shigellosis & Bacillary Dysentery - pages 601-3;

NOTE: Include discussion of difference between Shigellosis & Bacillary Dysentery in your answer.

Cholera - pages 599-601;
Pasteurella multocida Bite Wounds - pages 705-6;
Campylobacteriosis - pages 606-7;
Helicobacter pylori Gastric & Duodenal Ulcers and Gastric Cancer - pages 592-4;

NOTE: Include discussion of Gastric Cancer in your answer.

Cat Scratch Fever - pages 706-7;
Plague - Bubonic and Pneumonic - pages 723-6;

Note: Distinguish between bubonic and pneumonic plague. Describe the progression of bubonic plague. Describe the progression of pneumonic plague. Discuss Plague and bioterrorism.

Meningococcal Meningitis - pages 688-71;

Note: Include information on the meningococcal vaccine (strains it is effective against and recommendations concerning who gets vaccinated). Must discuss meningococcal disease in college students.

Gonorrhea - pages 644-6;
Gram Negative Septic Shock (also known as Septicemia or Endotoxic Shock) - pages 719-20;
Infections caused by Bacteroides fragilis and Other AGNB (Anaerobic Gram Negative Bacteria) - page 291;
Chlamydial sexually-transmitted disease - pages 646 & 292;

Note: Describe the morphology of the Elementary Body (EB).Describe the kinds of body cells that the EBs enter. One inside the body's cells, the EB reorganizes into the Reticulate Body (RB). Describe how the RB forms the inclusion and where the inclusion is located within the cell. Describe how long it takes for the infected cell to ruptureand what form of Chlamydia is released to infect other cells. Describe what serious complications can occur in the female due to chlamydial infection. Explain what % of sexually active women are estimated to be infected with Chlamydia. Describe the two kinds of lab tests used to detect Chlamydia. Explain how much of an increased risk of acquiring HIV there is for women infected with Chlamydia. Tell what % of 15- to 19-year-old girls are infected and what % of 20- to 24-year-old women are infected with Chlamydia.

Primary Atypical Pneumonia (Walking Pneumonia) - pages 578-9;

Note: Describe the complications of Mycoplasma pneumoniae infection. Tell how many cases and hospitalizations occur each year due to Mycoplasma pneumoniae infection. Tell how Mycoplasma pneumoniae is transmitted.

Syphilis - pages 648-52;

Describe the ways syphilis can and cannot be spread. Describe the stages of syphilis: primary stage, secondary stage, latent stage, and tertiary stage. Explain how immune complexes form during the secondary stage of syphilis. Describe how varied the rash can be in the secondary stage. Describe congenital syphilis. Explain why syphilis can recur.

Lyme Disease - pages 543-7;

Note: Give the common names and genus-species names for the types of ticks responsible for transmission of Lyme Disease. Name the types of persons at risk for Lyme Disease. Outline the two-year life cycle of the deer tick. Describe the reservoirs for Borrelia burgdorferi, the causative agent of Lyme Disease. Describe the vectors for Lyme Disease. Describe the mode of transmission for Lyme Disease to humans. Describe the progression of symptoms in Lyme Disease.