Chapter 10: Infection Control and the Clinical Laboratory

pathogen

harmful microorganism that can cause disease

How does infection occur?

When a pathogen enters the body and begins to multiply

microbe/microorganism

microscopic living organism

communicable

disease or virus that can easily spread from one person to another

healthcare associated infection (HAI)

an infection acquired during or after receiving care at a healthcare facility

nosocomial infection

specific type of HAI acquired in healthcare setting such as hospitals, outpatient clinics, or nursing homes

What are the most common HAIs and why?

• UTIs b/c of prolonged catheter use

• C diff

• Pneumonia

C diff

bacterium that causes inflammation of the colon by releasing toxins that damage the intestinal lining

MRSA (methicillin-resistant staphylococcus aureus)

type of bacteria that is resistant to several commonly used antibiotics; can cause infections in skin, lungs, or bloodstream; more difficult to treat

What is the chain of infection?

1. Infectious Agent: pathogen or disease causing microbe

2. Reservoir: environment where pathogen lives

3. Portal of Exit: pathogen’s exit pathway as it leaves one reservoir to enter another

4. Mode of Transmission: method by which the pathogen travels

5. Portal of Entry: the pathway the pathogen uses to enter a new host

6. Susceptible Host: individual who can become infected

Who are susceptible hosts?

Those with weakened immune systems, chronic illnesses, elderly, young children, those who fail to take appropriate protective measures

mode of transmission

the way a pathogen travels

airborne transmission

pathogen spreads through tiny infectious particles that remain suspended in the air

What are examples of pathogens that spread through airborne?

• Tuberculosis

• Measles

• Chicken pox

• Covid-19

• Disseminated herpes zoster

contact transmission

• Direct contact: physical interaction between infected and susceptible host- skin to skin or sexual contact

• Indirect contact: inanimate object contains bacteria or other pathogens deposited by an infected person

fomite

inanimate object that contains bacteria or other pathogens deposited by an infected person

What are examples of pathogens spread via contact?

• C diff

• MRSA

• Scabies

• Lice

• Norovirus

droplet transmission

occurs when an infected person releases respiratory droplets by coughing, sneezing, or talking; typically larger than airborne particles and travel only short distances and don’t stay suspended in the air for long

What are examples of diseases spread via droplet?

• Influenza

• Covid-19

• Common cold

• Strep throat

• Pneumonia

• Rubella

parenteral transmission

transfer of pathogens into the body through a route other than the digestive system (GI tract)

• needlesticks, cuts, puncture wounds, other breaches in skin like bites

What are examples of pathogens spread via parenteral?

• Hep B and C

• HIV

• Tetanus

vector transmission

spread of infection through insects or animals that act as disease carriers

Where do vectors carry pathogens?

Either on their surfaces or within their bodies

What are examples of diseases spread via vectors?

• Lyme disease

• West Nile virus

• Bubonic plague

• Malaria

vehicle transmission

occurs when pathogens are spread through a contaminated source such as food, water, blood, or meds

What are examples of pathogens spread via vehicle?

• Salmonella

• E coli

What is the most effective way to break the chain of infection?

Hand hygiene

What are examples of infection control methods?

• Hand hygiene

• Isolation

• Vaccination

• Aseptic technique

• Use of safety devices

• Early detection

• Healthy lifestyle

What vaccine are healthcare personnel strongly encouraged to get?

Hepatitis B

aseptic technique

practice of creating and maintaining an environment free from contamination by pathogens

How do you test for tuberculosis?

Quantiferon TB Gold Plus test

Why does the CDC maintain a list of communicable diseases?

To support surveillance, outbreak response, mandatory reporting, and the development of guidelines for diagnosis, treatment, and containment

transmission-based precautions

used when a patient is known or suspected to have an infection requiring extra protection

universal precautions

require healthcare workers to treat all blood, body fluids, and human tissues as if they are infectious

standard precautions

basic practices used with all patients regardless of diagnosis or infection status

What are some standard precautions?

• Hand hygiene

• PPE

• Respiratory hygiene

• Disinfect properly

What PPE is for contact precautions? droplet? airborne?

• Contact: gloves and gown

• Droplet: surgical mask

• Airborne: N95 or higher level respirator and place patient in an AIIR

accession number

unique identifier used to distinguish a sample from others

What department is the largest and most automated area of the laboratory?

Chemistry

coagulation department

analyzes specimens to evaluate clotting function and to detect defects in the blood’s ability to form clots

hematology department

analyzes blood to diagnose diseases and conditions related to blood cells and blood-forming tissues

immunohematology department

stores, separates, and tests blood for transfusion

microbiology department

tests blood, urine, stool, wound scrapings, and other specimens for presence of pathogenic microorganisms; culture and sensitivity test

pathology

study of disease through examination of tissues, organs, and bodily fluids

biopsies

small tissue samples taken from living patients

What is the second most commonly tested body fluid in the lab?

Urine