Comprehensive Guide to Microorganisms, Infection Chain, and Precautions in Healthcare

What are the two types of flora?

Resident flora (normal flora that is always present) and transient flora (occur in periods of limited duration).

Define pathogenicity.

The ability of a microorganism to produce disease; how effective a pathogen is at causing disease.

What is virulence?

The frequency and severity with which a pathogen causes disease.

List the four main categories of pathogens.

Bacteria, Rickettsiae, Viruses, Fungi, Protozoa, Helminths.

What are characteristics of bacteria?

Single-celled, lack a true nucleus, require oxygen for metabolism, multiply by simple cell division.

What diseases can bacteria cause?

Diarrhea, pneumonia, urinary tract infections.

How do Rickettsiae reproduce?

They act like intracellular parasites and need to be in living cells to reproduce.

What are examples of diseases caused by Rickettsiae?

Lyme disease, Rocky Mountain spotted fever, typhus.

What is a virus?

A microorganism that lives inside cells, cannot reproduce outside of cells, and can damage or kill the host cell.

What are examples of viral diseases?

Common cold, influenza, measles, hepatitis, HIV, COVID-19.

What are fungi?

Microscopic plants that do not cause disease but can produce mycoses.

What diseases can fungi cause?

Thrush, athlete's foot.

What are protozoa?

Single-celled, parasitic organisms that can move and obtain food from decaying organic matter.

What diseases are caused by protozoa?

Malaria, gastroenteritis, vaginal infections.

What are helminths?

Parasitic worms that can be contracted by eating undercooked meat or contaminated food or water.

What diseases can helminths cause?

Pinworms and tapeworms.

What are the six links in the chain of infection?

1) Infectious Agent 2) Reservoir 3) Portal of Exit 4) Mode of Transmission 5) Portal of Entry to Host 6) Susceptible Host.

What is an infectious agent?

Biological agents (living organisms), chemical agents (pesticides, food additives), and physical agents (heat, light, radiation) that cause infection.

What is a reservoir in the context of infection?

A place where pathogens survive and grow, often containing nutrients, moisture, and proper conditions.

What are fomites?

Objects or materials likely to carry infection.

What are the modes of transmission?

Contact transmission, droplet transmission, airborne transmission, vehicle transmission, vector transmission.

What is a susceptible host?

An individual who lacks resistance to a pathogen.

What is a nosocomial infection?

An infection acquired in a healthcare facility.

What are common types of nosocomial infections?

Urinary tract infections, surgical wounds, pneumonia, septicemia, MRSA, C. diff.

What is bioterrorism?

The use of living organisms as weapons to cause illness and spread fear.

What are examples of microorganisms used in bioterrorism?

Anthrax, pneumonic plague, tularemia, botulism.

What are standard precautions?

Precautions used for all patient care regardless of infection risk, including hand hygiene and personal protective equipment (PPE).

What is the sequence for putting on PPE?

Gown, mask/respirator, goggles/face shield, gloves.

What is isolation?

A private room with no shared supplies to prevent the spread of infection.

What are the stages of the infection process?

Incubation, Prodromal, Illness, Convalescence.