Pathogenic Microorganisms & Infection Control for Assistive Care (Outcome 4.3)

Chain of infection

A model that explains how an infection occurs through six predictable steps.

Infectious agent

The microorganism capable of causing disease, such as bacteria, viruses, fungi, or parasites.

Reservoir

The place where an infectious organism lives and multiplies, which can include people, animals, food, water, and surfaces.

Portal of exit

The route by which the pathogen leaves the reservoir, such as respiratory secretions, blood, or wound drainage.

Mode of transmission

The means by which the pathogen travels to a new host, such as through hands or contaminated surfaces.

Portal of entry

The route through which the pathogen enters a new host, like mucous membranes or non-intact skin.

Susceptible host

A person who can become infected, especially those with reduced defenses like the young or immunocompromised.

Contact transmission

The most common type of transmission, including direct contact (person-to-person) and indirect contact (through contaminated objects).

Droplet transmission

Transmission involving relatively large respiratory droplets produced during coughing or sneezing that travel short distances.

Airborne transmission

Transmission through very small particles that remain suspended in the air and can be inhaled by others.

Common vehicle transmission

Spread of organisms through contaminated food, water, medications, or equipment.

Vector-borne transmission

Transmission of pathogens through vectors like mosquitoes or ticks.

Bloodborne transmission

Spread of pathogens through exposure to blood and certain body fluids, commonly via needlesticks.

Hand hygiene

The practice of cleaning hands to physically remove organisms and reduce microbial load.

Environmental cleaning

The process of removing organic material from surfaces to improve the effectiveness of disinfectants.

Disinfection

The use of chemical agents to kill many pathogens on inanimate objects.

Sterilization

The complete destruction of all microbial life, including spores, used for critical items.

Antisepsis

The use of antiseptics to reduce microbes on skin before injections or minor wound care.

Personal protective equipment (PPE)

Clothing and devices that reduce exposure to infectious material.

Isolation precautions

Additional precautions taken based on how an organism spreads when Standard Precautions are insufficient.

Contact precautions

Precautions used for organisms that spread mainly by direct/indirect contact, requiring gloves and gowns.

Droplet precautions

Precautions for pathogens spread by respiratory droplets, requiring masks and eye protection.

Airborne precautions

Precautions for organisms that remain suspended in air, requiring fit-tested respirators.

Standard precautions

The baseline infection prevention practices used for all patients, regardless of their infection status.

Local signs of infection

Signs such as redness, warmth, swelling, pain, and drainage specific to an infection site.

Systemic signs of infection

Signs that reflect a body's broad response to infection, such as fever and malaise.

Colonization vs infection

Colonization indicates organisms are present but not causing symptoms, whereas infection means symptoms are present.