Infection Control & Immune Response – Lecture Vocabulary

100 key vocabulary flashcards covering pathogens, immunity, infection control, and antimicrobial concepts from the lecture.

Infection

The invasion and multiplication of pathogenic microorganisms in the body, causing tissue damage or disease.

Pathogen

Any microorganism (bacterium, virus, fungus, etc.) capable of producing disease.

Bacteria

Single-celled prokaryotes that reproduce by binary fission; may be harmless (normal flora) or pathogenic.

Virus

A tiny infectious agent that replicates only inside living cells and can be difficult to treat with drugs.

Fungi

Yeasts or molds that cause infections such as thrush or ringworm; thrive in warm, moist areas.

Helminth

Parasitic worm (e.g., tapeworm, hookworm) that can infect humans.

Protozoa

Single-celled eukaryotes (e.g., Giardia) that often spread by contaminated food or water.

Prion

Abnormal infectious protein particle that can trigger brain diseases like encephalitis.

Chain of Infection

The six links (agent, reservoir, portal of exit, mode, portal of entry, susceptible host) required for disease spread.

Reservoir

The place where a pathogen normally lives and multiplies (human, animal, soil, water, device).

Portal of Exit

Route by which a pathogen leaves the reservoir (cough, feces, blood, etc.).

Mode of Transmission

The way a pathogen is spread (contact, droplet, airborne, vector, vehicle).

Portal of Entry

Site through which a pathogen enters a new host (respiratory tract, skin break, mucous membrane).

Susceptible Host

A person with reduced resistance or immunity who can develop an infection.

Normal Flora (Microbiota)

Microbes that naturally inhabit the body and help protect against pathogens.

Aerobic Bacteria

Microorganisms that require oxygen to grow and multiply.

Anaerobic Bacteria

Microorganisms that grow in the absence of oxygen.

Staphylococcus Aureus

Common spherical bacterium; some strains (MRSA) are highly drug-resistant.

Streptococcus

Genus of chain-forming bacteria; causes strep throat, pneumonia, etc.

Escherichia coli (E. coli)

Gram-negative rod often living in the gut; a frequent cause of urinary tract infections.

Candida Albicans

Yeast responsible for thrush and vaginal yeast infections.

Ringworm

Contagious fungal skin infection producing ring-shaped lesions.

Tapeworm

Flat parasitic helminth acquired from under-cooked meat or contaminated food.

Pseudomonas aeruginosa

Opportunistic gram-negative rod; produces green-blue pus and strong odor.

Tuberculosis

Airborne disease caused by Mycobacterium tuberculosis; requires long-term therapy.

Influenza

Highly contagious viral respiratory illness; vaccine updated yearly.

COVID-19

Respiratory disease caused by the novel coronavirus discovered in 2019.

HIV

Human Immunodeficiency Virus; attacks CD4 T-cells and can lead to AIDS.

Sepsis

Life-threatening organ dysfunction from a dysregulated body response to infection.

Systemic Inflammatory Response Syndrome (SIRS)

Early, generalized inflammatory state (fever, tachycardia, tachypnea, leukocytosis).

Septic Shock

Severe sepsis with persistent low blood pressure despite fluid resuscitation.

Systemic Infection

Infection that has spread throughout the body via blood or lymph.

Local Infection

Infection confined to one area, showing redness, warmth, swelling, pain.

Inflammatory Response

Protective tissue reaction involving vasodilation, swelling, heat, pain, loss of function.

Vasodilation

Widening of blood vessels, increasing blood flow to injured tissue.

Exudate

Fluid rich in protein and cells that oozes from vessels during inflammation.

Phagocytosis

Process by which white blood cells engulf and destroy microbes or debris.

Plasma

Liquid portion of blood that carries proteins, antibodies, and clotting factors.

Leukocyte

General term for white blood cell, the body’s primary infection fighters.

Macrophage

Large phagocytic leukocyte that engulfs pathogens and dead cells.

Neutrophil

Most abundant white blood cell; first responder to bacterial invasion.

Immunoglobulin

Collective name for antibodies produced by B-cells.

IgG

Most common antibody; provides long-term immunity and crosses placenta.

IgA

Antibody found in mucous, saliva, tears; guards body entrances.

IgM

First antibody produced in an acute infection; large pentamer shape.

IgE

Antibody involved in allergic reactions and defense against parasites.

IgD

Antibody on B-cell surfaces; functions in B-cell activation.

Interferon

Antiviral protein released by infected cells to inhibit viral replication.

Lysosome

Cell organelle containing enzymes that digest microbes and debris.

Antigen

Any substance that triggers an immune response and antibody production.

Antibody

Protein that specifically binds an antigen to neutralize or mark it for destruction.

Vaccine

Preparation of antigenic material that induces adaptive immunity without causing disease.

Innate Immunity

Natural, non-specific defense present at birth (skin, mucous, phagocytes).

Acquired Immunity

Specific immunity developed after exposure to an antigen or vaccination.

Passive Immunity

Temporary immunity gained from another source (maternal antibodies, immunoglobulin therapy).

Active Immunity

Long-lasting immunity produced by one’s own immune system after infection or vaccination.

Herd Immunity

Community-level protection that occurs when enough people are immune to a pathogen.

Standard Precautions

Baseline infection-control measures applied to all patients (hand hygiene, gloves, etc.).

Transmission-Based Precautions

Additional infection-control steps based on route of spread (contact, droplet, airborne).

Contact Precautions

Gloves and gown used to prevent spread via direct or indirect touch.

Droplet Precautions

Mask and eye protection used for pathogens spread by large respiratory droplets (>5 µm).

Airborne Precautions

N95 respirator and negative-pressure room used for tiny droplet nuclei (<5 µm).

Personal Protective Equipment (PPE)

Gloves, gowns, masks, respirators, goggles, etc., worn to reduce exposure risk.

N95 Respirator

Tight-fitting mask that filters ≥95 % of airborne particles; requires fit testing.

Hand Hygiene

Most effective way to prevent infection spread; soap-and-water or alcohol rubs.

Aseptic Technique

Practices that reduce or eliminate pathogens during procedures.

Medical Asepsis

Clean technique aiming to decrease microbe numbers and prevent spread.

Surgical Asepsis

Sterile technique that keeps an area free of all microorganisms.

Sterilization

Process that destroys all forms of microbial life, including spores.

Disinfectant

Chemical used on non-living objects to kill most pathogenic microbes.

Healthcare-Associated Infection (HAI)

Infection acquired in a hospital or health care facility (previously nosocomial).

Methicillin-Resistant Staphylococcus Aureus (MRSA)

Strain of S. aureus resistant to beta-lactam antibiotics; requires contact precautions.

Vancomycin-Resistant Enterococcus (VRE)

Enterococcus species resistant to vancomycin; spread by contact with feces or surfaces.

Clostridioides difficile (C. diff)

Spore-forming bacterium causing antibiotic-associated colitis and profuse diarrhea.

Vancomycin

Potent glycopeptide antibiotic used IV for MRSA; monitor trough, beware ototoxicity.

Metronidazole (Flagyl)

Antibiotic/antiprotozoal drug often used IV or PO for C. diff and anaerobic infections.

Blood Culture

Laboratory test that grows microorganisms from blood to identify bloodstream infections.

Culture and Sensitivity (C&S)

Lab test that isolates a pathogen and determines which antibiotics kill it.

Peak Level

Highest drug concentration in blood, drawn shortly after dose to assess toxicity.

Trough Level

Lowest drug concentration before next dose; guides dosage for drugs like vancomycin.

Ototoxicity

Drug-induced damage to the ear causing hearing loss or tinnitus.

Red Man Syndrome

Histamine reaction (flushing, hypotension) from rapid IV infusion of vancomycin.

Urinary Catheter

Tube inserted into bladder to drain urine; increases risk for infection.

Catheter-Associated Urinary Tract Infection (CAUTI)

UTI that occurs in a patient with an indwelling catheter.

Ventilator-Associated Pneumonia (VAP)

Lung infection developing ≥48 h after intubation and mechanical ventilation.

Oral Care Bundle

Protocol using antiseptic swabs, moisturizers, etc., to reduce VAP risk.

Head-of-Bed Elevation

Raising HOB 30–45° to prevent aspiration and respiratory infections.

Foley Catheter

Indwelling urethral catheter with inflatable balloon for long-term drainage.

Straight Catheter (Intermittent)

Single-use catheter inserted to empty bladder, then removed immediately.

Antimicrobial Stewardship

Coordinated strategy to optimize antibiotic use and curb resistance.

Broad-Spectrum Antibiotic

Drug effective against a wide range of gram-positive and gram-negative bacteria.

Narrow-Spectrum Antibiotic

Drug aimed at a limited group of pathogens; preferred once C&S known.

Antibiotic Resistance

Ability of microbes to survive and grow despite antibiotic therapy.

Fecal Microbiota Transplant (FMT)

Transfer of screened donor stool to restore healthy gut flora in recurrent C. diff.

Pseudomembranous Colitis

Severe colon inflammation with plaques caused by C. diff toxins.

Clindamycin

Lincosamide antibiotic; high risk for triggering C. diff diarrhea.

Cephalosporin

Beta-lactam antibiotic class; overuse contributes to resistance and C. diff.

Penicillin

First widely used antibiotic class; some strains now resistant (e.g., MRSA).

Paxlovid

Oral antiviral (nirmatrelvir + ritonavir) used early in COVID-19 infection.

Remdesivir

IV antiviral used in hospitals to treat moderate-to-severe COVID-19.