PMLS LEC 2: Infection Control

Infection

is a condition that results when a microorganism (microbe for short) is able to invade the body, multiply, and cause injury or disease.

Microbes

include bacteria, fungi, protozoa, and viruses. that are pathogenic (causing or productive of disease) are called pathogens. We normally have many nonpathogenic microbes on our skin and in other areas such as the gastrointestinal (GI) tract. These microbes can become pathogens if they enter and multiply in areas of the body where they do not exist normally. Some microbes are pathogenic regardless of where they are found. Infections caused by pathogens can be local (restricted to a small area of the body) or systemic (sis-tem’ik), in which case the entire body is affected.

communicable diseases.

Some pathogenic microbes cause infections that are communicable (able to spread from person to person);

CENTERS FOR DISEASES CONTROL AND PREVENTION (CDC)

* is charged with the investigation and control of various diseases, especially those that are communicable and have epidemic potential.
* develops guidelines and recommends safety precautions to protect healthcare workers and others from infection.

Nosocomial infection

applies to infections acquired in hospitals.

Healthcare-associated infection (HAI)

applies to infections associated with healthcare delivery in any - healthcare setting, including home care.

Healthcare Infection Control Practices Advisory Committee (HICPAC)

advises the CDC on updating guidelines regarding the prevention of infections in hospitals and other healthcare facilities.

The National Institute for Occupational Safety and Health (NIOSH)

is responsible for conducting research and making recommendations for the prevention of work-related injury and illness.

CHAIN OF INFECTION

Infection transmission requires the presence of a number of components. The chain must be complete for an infection to occur. - If the process of infection is stopped at any component or link in the chain, an infection is prevented.

INFECTIOUS AGENT

also called the causative agent, is the pathogenic microbe responsible for causing an infection. Bacteria, fungus protozoon, rickettsia, virus

RESERVOIR

is the source of an infectious agent. It is a place where the microbe can survive and grow or multiply. The ability of these inanimate objects to transmit infectious agents depends upon the amount of contamination, the viability or ability of the microbe to survive on the object, the virulence or degree to which the microbe is capable of causing disease, and the amount of time that has passed since the item was contaminated. - Animal, human, equipment, food, water

EXIT PATHWAY

a way an infectious agent is able to leave a reservoir host. - Blood, exudates, excretions, secretions

MEANS OF TRANSMISSION

* is the method an infectious agent uses to travel
from a reservoir to a susceptible individual.
* Airborne, contact,droplet, vector, vehicle

ENTRY PATHWAY

the way an infectious agent is able to enter a susceptible host. - Body orifices, mucous, membranes, broken skin

SUSCEPTIBLE HOST

is someone with a decreased ability to resist infection

* A healthy person who has received a
vaccination against an infection with a particular
virus or recovered from one has developed
antibodies against that virus and is considered
to be immune, or unlikely to develop the
disease.
* Elderly, newborn, acute/chronically ill, immune
suppressed, unvaccinated
* Individuals who are exposed to the hepatitis B
virus (HBV) are less likely to contract the
disease if they have previously completed an
HBV vaccination series.

Airborne Transmission

involves dispersal of infectious agents that can remain infective for long periods of time in particles that are typically less than 5 µm in diameter and can be inhaled, such as droplet nuclei (residue of evaporated droplets).

airborne transmission activities

The particles, generated by sneezing, coughing, talking and activities that produce aerosols, can remain suspended in the air or in dust particles and become widely dispersed and eventually inhaled by susceptible individuals.

airborne infection isolation rooms (AIIRs)

Patients with airborne infections require this room that have special air handling and ventilation

examples of infectious agents spread by airborne transmission.

Mycobacterium tuberculosis, rubeola virus, and varicella virus

Contact Transmission

is the most common means of transmitting infection

Direct contact transmission

is the physical transfer of an infectious agent to a susceptible host through close or intimate contact such as touching or kissing.

Indirect contact transmission

can occur when a susceptible host touches contaminated objects such as patient bed linens, clothing, dressings, and eating utensils.

fomites

Inanimate objects that can harbor material containing infectious agents

Droplet Transmission

is the transfer of an infectious agent to the mucous membranes of the mouth, nose, or conjunctiva of the eyes of a susceptible individual via infectious droplets generated by coughing, sneezing, or talking or through procedures such as suctioning or throat swab collection.

Vector Transmission

is the transfer of an infectious agent carried by an insect, arthropod, or animal.

Vehicle transmission

is the transmission of an infectious agent through contaminated food, water, or drugs

example of vehicle transmission

The transmission of hepatitis viruses and HIV through blood transfusion is also considered vehicle transmission.

BREAKING THE CHAIN OF INFECTION

involves stopping infections at the source, preventing contact with substances from exit pathways, eliminating means of transmission, blocking exposure to entry pathways, and reducing or eliminating the susceptibility of potential hosts.

Joint Commission

requires every healthcare institution to have an infection-control program responsible for protecting patients, employees, visitors, and anyone doing business within healthcare institutions from infection.

Employee Screening and Immunization

Screening for infectious diseases typically takes place prior to or upon employment and on a regular basis throughout employment. Screening commonly includes tuberculosis (TB) testing, also called purified protein derivative (PPD) testing.

Evaluation and Treatment

provides for the evaluation and treatment of employees who are exposed to infections on the job. This includes OSHA-mandated confidential medical evaluation, treatment, counseling, and follow-up as a result of exposure to blood-borne pathogens.

Surveillance

This involves monitoring patients and employees at risk of acquiring infections as well as collecting and evaluating data on infections contracted by patients and employees.

Hand Hygiene

one of the most important means of preventing the spread of infection provided that it is achieved properly and when required. measures include the frequent use of antiseptic hand cleaners or hand washing, depending upon the degree of contamination

Use of Alcohol-Based Antiseptic

in place of hand washing as long as the hands are not visibly soiled. These products have been shown to have superior microbiocidal (destructive to microbes) activity.

Hand Washing

A 2-minute surgical hand scrub uses an antimicrobial soap or equivalent to remove or destroy transient microorganisms and reduce levels of normal flora prior to surgical procedures

Personal Protective Equipment (PPE)

are protective clothing and other items worn by an individual to protect mucous membranes, airways, skin and clothing from contact with infectious substances

Protective or reverse isolation

is used for patients who are highly susceptible to infections. In this type of isolation, protective measures are taken to keep healthcare workers and others from transmitting infection to the patient rather than vice versa.

Traditional Isolation System

At one time, the CDC recommended either of two types of isolation systems: the category-specific system and the disease-specific system.

Category Specific

had seven different isolation categories covering many diseases and often resulted in over isolation of patients and needless extra costs

The disease-specific system

was based on the modes of transmission of common diseases.

Universal Precautions

Isolation practices were altered dramatically in 1985, when the CDC introduced a strategy called universal precautions (UP) after reports of healthcare workers being infected with HIV through needlesticks and other exposures to HIV-contaminated blood.

Body Substance Isolation

Because infection transmission can occur before a diagnosis is made or even suspected, another system called body substance isolation (BSI) gained acceptance

Transmission-based precautions

are to be used for patients known or suspected to be infected or colonized with highly transmissible or epidemiologically (related to the study of epidemics) significant pathogens that require special precautions in addition to standard precautions.

Airborne precautions

or the equivalent, which must be used in addition to standard precautions for patients known or suspected to be infected with microorganisms transmitted by airborne droplet nuclei.

Droplet precautions

or the equivalent, which must be used in addition to standard precautions for patients known or suspected to be infected with microorganisms transmitted by droplets, generated when a patient talks, coughs, or sneezes and during certain procedures such as suctioning

Contact precautions

or the equivalent, which must be used in addition to standard precautions when a patient is known or suspected to be infected or colonized with epidemiologically important microorganisms that can be transmitted by direct contact with the patient or indirect contact with surfaces or patient-care items

SAFETY

Safe working conditions must be ensured by employers as mandated by the Occupational Safety and Health Act of 1970 and enforced by the Occupational Safety and Health Administration (OSHA).

BIOSAFETY

is a term used to describe the safe handling of biological substances that pose a risk to health.

Airborne (biohazard)

Biohazards can become airborne and inhaled when splashes, aerosols, or fumes are generated

Parental routes

There are many routes by which healthcare workers can be exposed to biohazards. Routes other than the digestive tract

Ingestion

Biohazards can be ingested if healthcare workers neglect to sanitize hands before handling food, gum, candy, cigarettes, or drinks. - Other activities that can lead to ingestion of biohazards include covering the mouth with hands instead of tissue when coughing or sneezing, biting nails, chewing on pens or pencils, and licking fingers when turning pages in books. - Frequent hand sanitization, avoiding hand-to-mouth activities, and refraining from holding items in the mouth or chewing on them provides the best defense against accidental ingestion of biohazardous substances.

Nonintact Skin

Biohazards can enter the body through visible and invisible pre-existing breaks in the skin such as abrasions, burns, cuts, scratches, sores, dermatitis, and chapped skin. - Defects in the skin should be covered with waterproof (nonpermeable) bandages to prevent contamination, even when gloves are worn.

Percutaneous

(through the skin) exposure to biohazardous microorganisms in blood or body fluid occurs through intact (unbroken) skin as a result of accidental needlesticks and injuries from other sharps including broken glass and specimen tubes. - Ways to reduce the chance of percutaneous exposure include using needle safety devices properly, wearing heavy-duty utility gloves when cleaning up broken glass, and never handling broken glass with the hands

Permucosal

(through mucous membranes) exposure occurs when infectious microorganisms and other biohazards enter the body through the mucous membranes of the mouth and nose and the conjunctiva of the eyes in droplets generated by sneezing or coughing, splashes, and aerosols and by rubbing or touching the eyes, nose, or mouth with contaminated hands.

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The chance of permucosal exposure can be reduced by following procedures to prevent exposure to splashes and aerosols and avoiding rubbing or touching the eyes, nose, or mouth.

BLOOD-BORNE PATHOGEN

is applied to any infectious microorganism present in blood and other body fluids and tissues.

Hepatitis B

(once called serum hepatitis) is caused by HBV, a potentially life-threatening blood-borne pathogen that targets the liver. (Hepatitis means “inflammation of the liver.”)

HBV Vaccination

The best defense against HBV infection is through HBV Vaccination

HBV Exposure Hazards

can be present in blood and other body fluids such as urine, semen, cerebrospinal fluid (CSF), and saliva.

Symptoms of HBV Infection

They include fatigue; loss of appetite;
mild fever; muscle, joint, and abdominal
pain; nausea; and vomiting.

* Jaundice appears in about 25% of
cases. About 50% of those infected
show no symptoms.
* Some individuals become carriers who
can pass the disease on to others.
* Carriers have an increased risk of
developing cirrhosis of the liver and liver
cancer.
* Infection is confirmed by detection of
hepatitis B surface antigen (HBsAg) in
an individual’s serum

Hepatitis C

caused by infection with HCV, has become the most widespread chronic bloodborne illness in the United States. - The virus, discovered in 1988 by molecular cloning, was found to be the primary cause of non-A, non-B hepatitis. No vaccine is currently available.

HCV Exposure Hazards

is found primarily in blood and serum, less frequently in saliva, and seldom in urine and semen.

* It can enter the body in the same
manner as HBV. However, infection
primarily occurs after large or multiple
exposures.
* As in the case of HBV, sexual contact
and needle sharing are the primary
means of transmission in nonmedical
settings.

Symptoms of HCV Infection

similar to those of HBV infection, although only 25% to 30% of infections even cause symptoms. - As with HBV, chronic and carrier states exist that can lead to cirrhosis of the liver and liver cancer. In fact, HCV infection is a leading indication for liver transplantation.

Human Immunodeficiency Virus (HIV)

attacks the body’s immune system, causing AIDS by leaving the body susceptible to opportunistic infections.

Opportunistic infections

are caused by organisms that would not ordinarily be pathogens to a normal healthy individual.

HIV Exposure Hazards

been isolated from blood, semen, saliva, tears, urine, cerebrospinal fluid, amniotic fluid, breast milk, cervical secretions, and tissue of infected persons. - The risk to healthcare workers, however, is primarily through exposure to blood. HIV can enter the body through all the same routes as the hepatitis viruses.

Symptoms of HIV Infection

The virus then enters a seemingly inactive incubation phase while hiding in the T lymphs. Certain conditions reactivate the virus, which slowly destroys the T lymphs. - Once the T lymph count is reduced to 200 or fewer per milliliter of blood, the patient is officially diagnosed as having AIDS, the third and final phase of infection.

Engineering controls

are devices that isolate or remove a BBP hazard.

Work practice controls

are practices that change the way tasks are performed to reduce the likelihood of BBP exposure.

Exposure Control Plan

To comply with the OSHA standard, employers must have a written exposure control plan. The plan must be reviewed and updated at least annually to document the evaluation and implementation of safer medical devices

BBP Exposure Routes

Occupational exposure
to blood-borne pathogens can occur if any of the
following happens while a healthcare worker is
performing his or her duties.

* The skin is pierced by a contaminated
needle or sharp object.
* Blood or other body fluid splashes into
the eyes, nose, or mouth.
* Blood or other body fluid comes in
contact with a cut, scratch, or abrasion.
* A human bite breaks the skin.

Exposure Incident Procedure

The immediate response by the
employee in the event of an exposure
incident includes the following:

* Needlestick or other sharps injury:
Carefully remove shards of glass or
other objects that may be embedded in
the wound and wash the site with soap
and water for a minimum of 30 seconds.
* Mucous membrane exposure: Flush the
site (i.e., eyes, nose, or mouth) with
water or sterile saline for a minimum of
10 minutes. Use an eyewash station if
available to adequately flush a splash to
the eyes.
* Remove contact lenses as soon as
possible and disinfect them before reuse
or discard.
* Report the incident to the immediate
supervisor.
* Report directly to a licensed healthcare
provider for a medical evaluation,
treatment if required, and counseling.

Surface Decontamination

OSHA requires surfaces in specimen collection and processing areas to be decontaminated by cleaning them with - a 1:10 bleach solution or other disinfectant approved by the Environmental Protection Agency (EPA).

Cleanup of Body Fluid Spills

Special EPA-approved chemical solutions and kits are available for cleanup of blood and other body fluid spills and for disinfecting surfaces. - Non-reusable items contaminated with blood or body fluids are biohazardous waste and must be disposed of in special containers or bags marked with a biohazard symbol.

Biohazard Waste Disposal

Filled biohazard waste containers require special handling prior to decontamination and disposal. - OSHA, EPA, and state and local agencies regulate biohazard waste disposal

ELECTRICAL SAFETY

Fire and electrical shock are potential hazards associated with the use of electrical equipment. - Knowledge of the proper use, maintenance, and servicing of electrical equipment such as centrifuges can minimize hazards associated with their use.

ACTIONS TO TAKE IF ELECTIC SHOCK OCCURS

* Shut off the source of electricity.
* If the source of electricity cannot be shut off,
use non conducting material (e.g., hand inside
a glass beaker) to remove the source of
electricity from the victim.
* Call for medical assistance.
* Start cardiopulmonary resuscitation if indicated.
* Keep the victim warm.

FIRE COMPONENTS

All employees of any institution should be aware of
procedures to follow in case of fifire.Fire
Components

* Four components, present at the same time, are
necessary for fire to occur.


1. Three of the components, fuel
(combustible material), heat to raise the
temperature of the material until it
ignites or catches fire, and oxygen to
maintain combustion or burning have
traditionally been referred to as the fire
triangle.
2. The fourth component, the chemical
reaction that produces fire creates a
fire tetrahedron

Class A fires

occur with ordinary combustible materials, such as wood, papers, or clothing, and require water or water-based solutions to cool or quench the fire to extinguish it.

Class B fires

occur with flammable liquids and vapors, such as paint, oil, grease, or gasoline, and require blocking the source of oxygen or smothering the fuel to extinguish.

Class C fires

occur with electrical equipment and require nonconducting agents to extinguish.

Class D fires

occur with combustible or reactive metals, such as sodium, potassium, magnesium, and lithium, and require dry powder agents or sand to extinguish (they are the most difficult figures to control and frequently lead to explosions)

Class K fires

occur with high-temperature cooking oils, grease, or fats and require agents that prevent splashing and cool the fire as well as smother it.

Fire Extinguishers

There is a fire extinguisher class that corresponds to each class of fire except class D. - Class D fires present unique problems and are best left to firefighting personnel to extinguish. Using the wrong type of fire extinguisher on a fire can be dangerous. Common fire extinguisher classes and how they typically work are as follows:

Class A extinguishers

use soda and acid or water to cool the fire

Class B extinguishers

use foam, dry chemical, or carbon dioxide to smother the fire.

Class ABC (multipurpose) extinguishers

use dry chemical reagents to smother the fifire. They can be used on class A, B, and C fires

Class K extinguishers

use a potassium-based alkaline liquid specifically formulated to fight high-temperature grease, oil, or fat fires by cooling and smothering them without splashing. Some class K extinguishers can also be used on class A, B, and C fires.

RACE

R-Rescue individuals in danger.

A-Alarm: activate the fire alarm.

C-Confine the fire by closing all doors and windows.

E-Extinguish the fire with the nearest suitable fire extinguisher

Radiation Safety

The principles involved in radiation exposure are distance, shielding, and time. - This means that the amount of radiation you are exposed to depends upon how far you are from the source of radioactivity, what protection you have from it, and how long you are exposed to it.

A clearly posted radiation hazard symbol is required in areas where radioactive materials are used and on cabinet or refrigerator doors where radioactive materials are stored.• A phlebotomist may encounter radiation hazards when collecting specimens from patients who have been injected with radioactive dyes, when collecting specimens from patients in the radiology department or nuclear medicine, and when delivering specimens to radioimmunoassay sections of the laboratory

An important chemical safety rule to remember when dealing with acids and other liquids is

never add water or other liquids to an acid, as it can cause an explosive type reaction.

OSHA Hazard Communication Standard

to protect employees who may be exposed to hazardous chemicals. - According to the law, all chemicals must be evaluated for health hazards, and all chemicals found to be hazardous must be labeled as such and the information communicated to employees.

HazCom Labeling Requirements

Although labeling format may vary by
company, all chemical manufacturers
must comply with labeling requirements
set by the Manufacturers Chemical
Association. Labels for hazardous
chemicals must contain:

* A statement of warning such as “danger”
or “poison”
* A statement of the hazard (e.g., toxic,
flammable, combustible)
* Precautions to eliminate risk
* First aid measures in the event of a spill
or other exposure

Material Safety Data Sheets

An MSDS contains general information as well as precautionary and emergency information for the product. - Every product with a hazardous warning on the label requires an MSDS to help ensure that it will be used safely and as intended

Department of Transportation Labeling System

Hazardous materials may have additional labels of precaution, including a Department of Transportation (DOT) symbol incorporating a United Nations hazard classification number and symbol. The DOT labeling system uses a diamond-shaped warning sign.

National Fire Protection Association Labeling System

This system uses a diamond-shaped
symbol divided into four quadrants:


1. Health hazards are indicated
in a blue diamond on the left.
2. The level of fire hazard is
indicated in the upper
quadrant in a red diamond.
3. Stability or reactivity
hazards are indicated in a
yellow diamond on the right
4. Other specific hazards are
indicated in a white quadrant
on the bottom.

Safety Showers and Eyewash Stations

The phlebotomist should know the location of and be instructed in the use of safety showers and eyewash stations in the event of a chemical spill or splash to the eyes or other body parts. - The affected parts should be flushed with water for a minimum of 15 minutes,followed by a visit to the emergency room for evaluation.

Chemical Spill Procedures

Chemical spills require cleanup using
special kits containing absorbent and
neutralizer materials.

* The type of materials used depends
upon the type of chemical spilled.
* An indicator in the cleanup materials
detects when the materials have been
neutralized and are safe for disposal.
* The EPA regulates chemical disposal.

External Hemorrhage

hemorrhage
(abnormal or profuse bleeding) from an
obvious wound can be effectively
controlled by firmly applying direct
pressure to the wound until bleeding
stops or EMS rescuers arrive.

* Pressure should be applied using cloth
or gauze, with additional material added
if bleeding continues.
* It is acceptable to use an elastic
bandage to hold the compress in place
as long as pressure is applied to the
bandage.
* Standard precautions should be
followed.


1. Using a tourniquet to control
bleeding can be harmful and
is not recommended.
2. A tourniquet should be used
only as a last resort to save a
life after all other means to
control bleeding are
unsuccessful, as may occur
with an avulsion (a tearing
away or amputation of a body
part) or a severely mangled or
crushed body pa

Shock

results when there is insufficient return of blood flow to the heart, resulting in an inadequate supply of oxygen to all organs and tissues of the body

Cardiopulmonary Resuscitation (CPR) and Emergency Cardiovascular Care (ECC)

most phlebotomy programs require it as a prerequisite or corequisite or include it as part of the course