Unit 5
Microorganisms
Bacteria
Virus
Fungi
Protozoa
Host
Infection
Pathogen
Reservoir
Flora
Fomites
Natural Resistance
Active Immunity (Natural Immunity)
Active Immunity (Artificial Immunity)
Vaccine
Toxoid
Passive Immunity (Artificial Immunity)
Standard Precautions
Transmission-Based Precautions
Asepsis
Medical Asepsis
Surgical Asepsis
Sterilization
Hand Hygiene
Introduction to Radiologic Sciences and Patient Care 5th Edition ( Adler and Carlton)
Chapter 16 - Pages 199-215
Here is what you must complete within Unit 5!!!
1. Reading Assignment
2. Read through the Lesson (Read supplemental documents = Radiology Department Infection Control Procedures and Isolation Guidelines)
3. Complete Discussion #4 (post your response, read the responses of your classmates and respond to them with any comments you may have)
4. Complete the Unit 5 Exam
Microorganisms - Microscopic are living organisms (too small to be seen with the naked eye). Many can grow in or on a host organism and cause disease.
Types: bacteria, viruses, fungi and protozoa
Bacteria - A very small single cell organism. It has a cell wall and an atypical nucleus that lacks a membrane. It can replicate without a host cell.
Classified according to shape: spherical (Cocci), rod-shaped (Bacilli) and spiral (spirilla or spirochetes).
Virus - A small infectious agent that can replicate only inside the living cells of an organism (a virus cannot live outside a living cell).
Fungi (fungus is singular) - Can be single-celled, multinucleated or multicellular organisms. They include yeasts, molds and mushrooms.
Protozoa (protozoon is singular) - A subkingdom comprising the simplest organisms of the animal kingdom, consisting of unicellular organisms ranging in size from submicroscopic to macroscopic.
Host - An animal or plant that harbors or nourishes another organism.
Infection - Invasion by and multiplication of pathogenic microorganisms in a bodily part or tissue, which may produce subsequent tissue injury and progress to overt disease through a variety of cellular or toxic mechanisms.
Pathogen - Any microorganism capable of producing disease.
Reservoir - Person or animal that harbors pathogenic microorganisms but does not have the clinical disease. Serves as a source from which other individuals can be infected.
Flora - Microorganisms that live on or within a body to compete with disease-producing microorganisms and provide a natural immunity against certain infections. Flora are found on or in a healthy person.
Fomites (Fomes) - Nonliving articles, such as clothing, that can transmit microorganisms.
Exogenous mode of transmission is from outside the body.
Examples: (1) a mosquito, tick or flea (2) a fomite, such as a cassette would be exogenous (3) West Nile virus would be exogenous.
Endogenous mode of transmission from within one's own body.
Example: Normal flora (bacteria in the mouth)
The cycle of infection is the factors that are involved in the spread of the disease. These factors are:
The Person Transmitting The Disease Has---
1. An infectious organism
2. A reservoir of infection
3. A portal of exit
The Person Contracting The Disease--
4. Is a susceptible host
5. Has a portal of entry
6. There is a means of transporting the organism from the reservoir to the susceptible individual
There are many factors involved in the establishment of an infectious disease. The process includes:
1. Encounter - The infectious organism comes into contact with the host.
2. Entry - An infectious microbe enters the body by either ingression or penetration.
3. Spread - The dissemination of the microbe through the body.
4. Multiplication - Most infectious agents must first multiply for the impact to be recognized.
5. Damage - There are innumerable ways in which an infectious agent can cause damage to a host. The damage can be either direct or indirect.
6. Outcome - There are three possible outcomes:
A. The host gains control of the infectious agent and eliminates it.
B. The infectious agent overcomes the host's immunities to cause disease.
C. The host and the infectious agent compromise and live in a somewhat anxious state of symbiosis.
The body has three protective barriers from invasion of microorganisms.
1. Natural Resistance - These are mechanical barriers such as intact skin and mucous membranes that keep out microorganisms.
2. Active Immunity (Natural Immunity) - The production of antibodies causing a person to become immune to an antigen. Occurs naturally by exposure to disease.
Active Immunity (Artificial Immunity) - A person forms antibodies to counteract an antigen in the form of a vaccine or a toxoid.
Vaccine - Consists of a low dose of dead or deactivated bacteria or viruses that stimulate the body to produce antibodies against them.
Toxoid - A chemically altered tocsin. The poisonous material produced by a pathogenic organism that triggers the development of antibodies.
Examples - Vaccines for smallpox, polio, tetanus and diphtheria.
3. Passive Immunity (Artificial Immunity) - The administration of the dose of preformed antibodies from the immune serum of an animal, usually a horse.
A. Used when a person is exposed to serious disease, but has no immunity against it.
B. The exposure requires an immediate supply of antibodies to prevent a possible fatal infection (hepatitis, rabies and tetanus).
Isolation precautions are used to reduce transmission of microorganisms in healthcare and residential settings.
These measures are designed to protect patients/residents, staff and visitors from contact with infectious agents.
There are two categories of isolation precautions:
1. Standard Precautions
2. Transmission-Based Precautions
Standard precautions are a set of basic infection prevention practices intended to prevent transmission of infectious diseases from one person to another.
Because we do not always know if a person has an infectious disease, standard precautions are applied to every person, every time to assure that transmission of disease does not occur.
Standard precautions were previously called "universal precautions."
Standard precautions include:
1. Hand Hygiene
2. Personal Protective Equipment
3. Patient Care Equipment
4. Environmental Control
5. Linen
6. Needles and Other Sharps (Needles should not be recapped. Most have a safety cap, if not, put it directly in the sharps container.)
7. Resuscitation Practices
8. Patient Placement
9. Respiratory Hygiene and Cough Etiquette
10. Safe Injection Practices to Prevent Infections in Patients
11. Infection Control Practices for Special Lumbar Puncture Procedures
The use of transmission-based precautions is the CDC's current recommendation for isolating patients with known infections.
A. Examples: MRSA, VRE, E. Coli, clostridium difficile, hepatitis A and impetigo
B. PPE (Personal Protective Equipment): Gown and gloves (gowns and gloves should be removed and hands washed before leaving the patient's room)
C. Other Precautions: Patients must wear a mask and impervious gown when they leave their room.
2. Transmission by Droplet - Infection occurs when infected person coughs, sneezes or talks spraying the pathogens on previously uninfected person
A. Examples: Influenza, diptheria, common cold, rubella, mumps and pneumonia
B. PPE: Mask
C. Other Precautions: Patients should wear a surgical mask when they leave their room.
3. Airborne Transmission - Infected droplets or evaporated droplets suspended in air or infected dust particles are inhaled by the host (respiratory isolation)
A. Examples: Tuberculosis, chickenpox and measles
B. PPE: Particulate respirators
C. Other Precautions: Patient rooms must have negative air flow and the doors should remain shut at all times. Patients must wear surgical mask to filter expired air when they leave their room.
GO BACK TO THE COURSE CONTENT, UNIT 5 AND CLICK ON THE ISOLATION GUIDELINES DOCUMENT!!! READ THROUGH THE GUIDELINES AND THEN COME BACK TO THE LESSON!
Here are some additional isolation procedures and techniques that can be followed when working with different types of wounds and diseases.
Isolation Unit or Room - A cubicle or room set up to separate persons with communicable disease from other persons.
Wound and Skin Precautions
Wound and skin precautions are used when the pathogenic microorganisms may be spread by direct contact or indirect contact with purulent material or drainage from an infected body site. This can include burns that do not extend over the entire body, gangrene or skin and wound infections caused by staphylococci, streptococci, or other microorganisms. A private room is not indicated. A gown and gloves are worn if the health worker will be in direct contact with the patient. Masks are not worn. Any articles used that come into direct contact with the patient must be isolated and discarded or bagged and labelled. Hands are washed using medical aseptic technique before and after patient care.
Respiratory Isolation Technique
This is designed to prevent transmission of infectious diseases over short distances through the air. Direct and indirect contact transmission may occur but is infrequent. Diseases requiring respiratory isolation include measles, mumps, and rubella. A private room is required or patients with the same disease may share a room. A mask and gloves are worn. Medical aseptic hand washing is used before entering the room and when leaving. All articles must be disinfected.
Enteric Isolation Technique
Enteric isolation technique is used when the patient has a disease that may be transmitted by direct contact or indirect contact with infected feces. This type of isolation is used for diarrheal diseases; gastroenteritis caused by Escherichia coli, salmonella, shigella, hepatitis A or B, or unspecified hepatitis. A private room is indicated if patient hygiene is poor and thus at risk of contaminating others and for children. Gowns and gloves should be worn. Hands must be washed before and after the procedure. Contaminated articles should be discarded or bagged and labelled.
Strict Isolation Technique
Strict isolation technique is used to prevent transmission of highly contagious or virulent infections that may be spread by air or contact. A private room is required. A gown, mask and gloves must be worn. Contaminated articles used in the room must be specifically cared for by being discarded or bagged and labelled before being sent for decontamination and reprocessing. Hands must be washed after leaving the room.
Protective (Reverse) Isolation Technique
Protective isolation technique is used to protect a particularly susceptible patient from becoming infected. Patients who require this type of isolation are those with AIDS, infected burns, acute leukemia or lymphoma, large areas of denuded skin due to injury or disease, immunosuppressive therapy (organ transplant recipients), neutropenia, on anti-cancer chemotherapy severely immunocompromized patients and infants in critical care nurseries. A private room is required. The technique is similar to aseptic technique as practiced in the operating room. The mobile unit must be thoroughly cleaned before entering the unit and IRs must be encased in sterile covers. A sterile gown, gloves and a mask are donned as in sterile procedures. The technologist must plan his work carefully and work with an assistant to avoid contaminating the patient. Trips in and out of the reverse isolation room must be kept to a minimum.
Blood/body Fluid Precautions
Blood / body fluid precautions are designed to prevent infections that are transmitted by contact with blood or other body fluids such as HIV and HBV. A private room is indicated if patient hygiene is poor because of the higher risk to others. Masks are not indicated. Gowns are only indicated if soiling is likely. Masks are not indicated but gloves should be worn. Hands must be washed before and after touching the patient or contaminated articles. Contaminated articles should be discarded or bagged and labelled. Care should be taken to avoid needle-stick injuries. Used needles should not be recapped or bent; they should be placed in a prominently labelled, puncture-resistant container designated specifically for such disposal. Blood spills should be cleaned up promptly with hypochlorite.
To maintain strict isolation while making a radiographic exposure, two technologists are required. The technologists should have the mobile unit and the correct number of image receptors (IR) prepared before entering the room, regardless of the type of isolation room. A plastic covering will be needed in order to protect the IR and the patient from contamination. The method described below specifies strict isolation, but variations are followed for other classifications of isolation.
You can use the "clean tech", "dirty tech" technique.
One Technologist will stay clean by only touching the radiographic equipment (only the objects that have not been contaminated). The other technologist will be the one touching the patient and the covered image receptor (both contaminated items). This way everything will not be contaminated.
1. Remove your watch and any rings you are wearing. Pin them to your uniform or put them in your pocket.
2. Push the mobile unit into the room. Have an IR housed in a protective case and ready for use.
3. Wash your hands.
4. There will be disposable masks, gowns, caps and gloves available.
5. A head covering is required for long hair and regardless of hair length if dealing with patients with certain specific diseases.
6. Remove a mask from the container and put it on. Do not wear the same mask for more than 20 minutes. After that time, it has become contaminated and you are no longer protected.
7. Take a clean gown (gowns should be folded in the same manner as surgical scrub gowns). Hold it at the neck and let it unfold.
8. Put both arms into the sleeves of the gown and work it on. Do not touch the outside of the gown.
9. Use one covered hand to pull on the sleeve. Then pull on the other sleeve.
10. Tie the neck ties of the gown. Be certain that the gown covers your clothing.
11. Tie the waist ties of the gown.
12. Put on gloves.
13. Approach the patient and greet him. Explain what you must do.
14. Place the IR under the patient.
15. Adjust the machine. Make the necessary exposures.
16. When the exposures are made, have your assistant waiting outside the door. Fold the cuff of the protective case back so that the edge of the IR is free. Do not touch the outside of the protective case.
17. Your assistant should grasp the IR and remove it from the case. Make the patient comfortable.
18. Pull and tear gown to remove and fold it forward so that the inside of the gown is facing outside.
19. Remove gloves
20. Drop the soiled gown and gloves into the receptacle prepared for it.
21. Untie mask ties. Hold the mask only by the strings and dispose of it.
22. Remove cap without touching your hair and dispose of it.
23. Wash your hands and dry them thoroughly. Do not touch faucet handles with bare hands. Use paper towels.
24. Leave the room. Cleanse the mobile unit thoroughly with an antiseptic solution.
25. Wash your hands once again.
Asepsis - Freedom from infection. There are two categories of the asepsis.
1. Surgical Asepsis - The procedure used to prevent contamination microbes and endospores before, during and after surgery using sterile technique.
2. Medical Asepsis - A reduction in the numbers of infectious agents, which in turn decreases the probability of infection but does not necessarily reduce it to zero.
So, hand washing does not use sterile technique, therefore, it is not part of surgical asepsis. Your hands will not be sterile after washing them. Wearing sterile gloves is using sterile technique. Hand washing is reducing infectious agents to try to decrease the chance of getting an infection and to keep from spreading infection.
Disinfectant - Liquid chemical agent applied to objects to eliminate or destroy many or all pathogenic microorganisms.
Antiseptic - A disinfectant agent that inhibits growth and development of microorganisms, applied topically.
Antibacterial - A substance that kills bacteria or inhibits their growth or replication.
Bacteriostatic Agent -Stops bacteria from reproducing (bacteriostatic antibiotics)(bacteriostatic agents are not applied topically).
Antimicrobial Agent - An agent that kills microorganisms or inhibits their growth.
Iatrogenic - Caused by a medical professional.
Nosocomial - Infections brought on due to hospital (acute care facility) stay.
Community Acquired - Infections developed outside the healthcare facility.
Infection - An invasion of body tissues.
Disease - Abnormal change in the function or structure of a body part or organ system (sickness).
Vector - A carrier, especially an animal, that transfers an infective agent from one host to another.
Vehicle - Any substance, such as food or water, that can serve as a mode of transmission for infectious agents.
Sterilization is the process used for the complete destruction or elimination of all living microorganisms. It is the treatment used to make an item germ-free.
There are several processes that are used for sterilization.
Autoclaving (Steam Under Pressure)
Gas
Gas Plasma
Chemicals
Dry Heat
1. Autoclaving (Steam Under Pressure)
The most commonly used method of sterilization and is most practical in the hospital setting for items that can withstand heat and moisture.
It is an effective, economical and convenient method for items that can withstand high temperatures and moisture. Pressure is attained in a chamber called an autoclave.
2. Gas Sterilization
Method of choice for items that cannot withstand high temperatures and moisture. A mixture of ethylene oxide and freon is used because ethylene oxide alone is flammable and explosive. Should not be used for items that can be sterilized with steam. Items have to be sent to central supply to be gas sterilized because the gases are poisonous and there must be proper aeration in a controlled environment.
3. Gas Plasma Sterilization
Items are cleaned, wrapped and placed in a mobile unit where they will be exposed to hydogren peroxide gas plasma. The gas enters the wrapped instruments to sterilize them.
4. Chemicals
One of the least satisfactory means of sterilization. Used when item cannot withstand heat, when gas sterilization is not available or when aeration time is lengthy. Only those chemicals registered as sterilants by the US Environmental Protective Agency and used as directed by the manufacturer may be utilized.
5. Dry Heat
Uses high heat of 329-338 degrees F. Used more in Great Britain and tropical countries. Good for powders, ointments and sealed tubes and containers.
Time needed for sterilization varies from 1 to 6 hours.
Hand hygiene refers to decontamination of the hands using soap and water, alcohol-based hand rubs or an antiseptic hand wash.
Handwashing is the single most important means of preventing the spread of infection. You must wash your hands before and after each patient, whether gloves are worn or not.
Handwashing falls into the category of medical asepsis.
An alcohol-based hand sanitizer can be used when soap and water are not available. It should only be used when the hands are not visibly soiled. If the hands are visibly soiled, they should be washed
with soap and water.