INFECTION CONTROL

INFECTION CONTROL

Measures used to prevent the spread of microorganisms and protect patients, healthcare workers, and visitors.

NOSOCOMIAL INFECTION

Infection acquired while receiving medical care; also called a hospital-acquired infection (HAI).

IATROGENIC INFECTION

Infection resulting from a medical treatment, diagnostic test, or therapeutic procedure.

COMMUNITY-ACQUIRED INFECTION

Infection already present before a person enters a healthcare facility.

MICROORGANISM

A microscopic living organism that may or may not cause disease.

BACTERIA

Single-celled prokaryotic microorganisms containing both DNA and RNA.

PROKARYOTE

Organism without a true nucleus or membrane-bound organelles.

ENDOSPORE

Thick protective coating formed by some bacteria during unfavorable conditions for survival; highly resistant to heat, chemicals, and drying.

DORMANCY

Inactive or hibernation stage of an endospore that may last months to years.

GERMINATION

Process in which an endospore returns to its active bacterial form when conditions become favorable.

AEROBES

Bacteria that require oxygen to live and grow.

ANAEROBES

Bacteria that grow without oxygen; some are killed by oxygen.

MYCOBACTERIUM TUBERCULOSIS

Example of an aerobic bacterium that causes tuberculosis (TB).

COCCI

Spherical or round-shaped bacteria.

BACILLI

Rod-shaped or oblong bacteria.

SPIRILLA

Spiral-shaped bacteria.

COCCOBACILLI

Short rod-shaped bacteria.

PLEOMORPHIC

Bacteria with no definite or consistent shape.

DIPLOCOCCI

Cocci arranged in pairs.

STREPTOCOCCI

Cocci arranged in long chains.

STAPHYLOCOCCI

Cocci arranged in irregular grape-like clusters.

FUNGI

Eukaryotic microorganisms that usually grow in warm, moist, aerobic environments.

YEAST

Single-celled fungus that reproduces by budding.

BUDDING

Asexual reproduction in yeast where a new cell grows from the parent cell.

MOLD

Multicellular fungus that reproduces by spores.

SPORES

Reproductive structures produced by molds for multiplication and spread.

DIMORPHIC FUNGI

Fungi that exist as molds in the environment and as yeast in the human body.

SAPROPHYTES

Fungi that obtain nutrients from dead or decaying organic matter.

PARASITE

Organism that lives on or inside another organism (host) at the host's expense.

HOST

Organism that provides nourishment and shelter for a parasite.

PROTOZOA

Complex single-celled parasites that often move using flagella or cilia.

FLAGELLA

Long whip-like projections used by protozoa for movement.

CILIA

Short hair-like projections used by protozoa for movement.

HELMINTHS

Parasitic worms that live inside the human body.

PLATYHELMINTHES

Flatworms classified as helminths.

ASCHELMINTHES

Roundworms classified as helminths.

VIRUS

Acellular infectious agent that contains either DNA or RNA and requires a host cell to reproduce.

ELECTRON MICROSCOPE

Instrument required to visualize viruses because they are too small to be seen with a light microscope.

CAPSID

Protein coat surrounding and protecting the genetic material of a virus.

CAPSOMERES

Protein subunits that make up the viral capsid.

LYTIC CYCLE

Viral reproductive cycle in which the virus invades, replicates, and destroys the host cell.

INFECTIOUS AGENT

Disease-causing microorganism that initiates infection.

PATHOGENICITY

Ability of a microorganism to cause disease.

VIRULENCE

Degree of pathogenicity or ability of a microorganism to multiply and cause severe disease.

INVASIVENESS

Ability of a microorganism to enter and spread through body tissues.

SPECIFICITY

Preference of a microorganism for a particular host or tissue.

RESERVOIR

Natural environment where microorganisms live, grow, and multiply.

PORTAL OF EXIT

Route through which microorganisms leave the reservoir.

MOUTH

Common portal of exit for respiratory pathogens.

RECTUM

Portal of exit for pathogens spread through feces.

URINARY TRACT

Portal of exit for pathogens spread through urine.

MEANS OF TRANSMISSION

Method by which microorganisms spread from one host to another.

DIRECT CONTACT

Transmission through immediate physical contact such as touching, kissing, or sexual intercourse.

INDIRECT CONTACT

Transmission through contaminated objects or fomites.

FOMITES

Inanimate objects capable of carrying and transmitting pathogens (e.g., doorknobs, phones, medical equipment).

DROPLET TRANSMISSION

Spread of pathogens through respiratory droplets produced by coughing, sneezing, talking, or saliva, usually within 3-5 feet.

VEHICLE TRANSMISSION

Spread of pathogens through contaminated food, water, blood, drugs, or medical solutions.

VECTOR TRANSMISSION

Spread of pathogens through insects or animals such as mosquitoes.

AIRBORNE TRANSMISSION

Spread of pathogens through tiny particles suspended in the air and inhaled by others.

PORTAL OF ENTRY

Route through which microorganisms enter a new host to cause infection.

INGESTION

Entry of pathogens through the digestive tract by swallowing contaminated food or water.

INHALATION

Entry of pathogens through breathing contaminated air.

INJECTION

Entry of pathogens through needles or punctures in the skin.

MEDICAL ASEPSIS

Microorganisms have been eliminated through the use of soap, water, friction, and various chemical disinfectants.

SURGICAL ASEPSIS

Means that microorganisms and their spores have been completely destroyed by means of heat or by a chemical process.

DISINFECTION

the removal, by mechanical and chemical processes, of pathogenic microorganisms, but frequently not their spores, from objects or body surfaces.

ALCOHOL (70-90%)

Disinfectant used for thermometers, medication vials, and small medical equipment; effective against bacteria and many viruses.

GLUTARALDEHYDE

High-level disinfectant used for endoscopes, thermometers, and rubber or heat-sensitive medical equipment.

CHLORINE COMPOUNDS

Disinfectants used for countertops, floors, and other environmental surfaces; effective against a wide range of microorganisms.

HYDROGEN PEROXIDE

Disinfectant used for environmental surfaces (commonly outside healthcare settings) due to its oxidizing antimicrobial action.