Microexam 3

Incidence

Number of new cases in a given time period.

Prevalence

Total number of existing cases.

Mortality

Number of deaths from a disease.

Endemic

Constant presence of a disease in a population.

Epidemic

Sudden increase in disease cases.

Pandemic

Worldwide spread of disease.

Prodrome

Early stage of disease with vague symptoms such as fever and aches.

Zoonotic disease

Disease transmitted from an animal reservoir to humans.

Vector

Living organism that transmits a pathogen.

Reservoir

Natural habitat where a pathogen normally lives.

Sterilization

Destruction or removal of all microorganisms including endospores.

Disinfection

Destruction of vegetative pathogens on objects.

Antisepsis

Destruction of microbes on living tissue.

Sanitization

Reduction of microbial population to safe public levels.

Pasteurization

Use of heat to reduce pathogens and spoilage organisms.

HTST pasteurization

72°C for 15–30 seconds.

Cold sterilization

Use of gamma radiation to sterilize foods or materials.

D-value

Time required to kill 90% of a microbial population.

Alcohols

Disinfectants that denature proteins and disrupt membranes.

Isopropanol

Common antiseptic alcohol.

Halogens

Disinfectants such as iodine and chlorine.

Iodine

Halogen antiseptic.

Chlorine

Halogen disinfectant used in bleach.

Phenolics

Disinfectants that disrupt membranes and proteins.

Aldehydes

Strong disinfectants such as formaldehyde.

Detergents

Surfactants that disrupt cell membranes.

Chlorhexidine

Common detergent antiseptic.

Zephiran

Quaternary ammonium detergent disinfectant.

Denaturation

Loss of protein structure and function.

Selective toxicity

Drug harms microbe without harming host.

Broad-spectrum antibiotic

Effective against many bacteria.

Narrow-spectrum antibiotic

Effective against limited groups of bacteria.

Bactericidal

Kills bacteria.

Bacteriostatic

Inhibits bacterial growth.

Beta-lactam antibiotics

Inhibit bacterial cell wall synthesis.

Oxacillin

Beta-lactam antibiotic.

Mycoplasma

Bacteria lacking a cell wall.

Antibiotic resistance

Ability of bacteria to survive antibiotic treatment.

Tuberculosis

Disease commonly treated with isoniazid, rifampin, ethambutol.

Isoniazid

Tuberculosis drug.

Rifampin

Tuberculosis drug.

Ethambutol

Tuberculosis drug.

Mutualism

Both microbe and host benefit.

Commensalism

Microbe benefits, host unaffected.

Parasitism

Microbe benefits, host harmed.

Virulence

Degree of pathogenicity.

Adhesins

Molecules that help pathogens attach to host cells.

Capsule

Protective layer that resists phagocytosis.

Superantigens

Virulence factors that overstimulate immune response.

Viral infection

May cause cell lysis, cell fusion, or cancer transformation.

Innate immunity

Nonspecific defense present at birth.

Adaptive immunity

Specific acquired immune response.

Humoral immunity

Antibody-mediated immunity by B cells.

Cell-mediated immunity

Immunity involving T cells.

B lymphocytes

Cells that produce antibodies.

Plasma cells

Activated B cells that secrete antibodies.

Memory cells

Long-lived cells responsible for faster secondary response.

T lymphocytes

Cells involved in cell-mediated immunity.

Helper T cells

T cells that activate other immune cells.

Cytotoxic T cells

T cells that kill infected host cells.

Natural killer cells

Kill virus-infected and tumor cells.

CD4

Receptor on helper T cells that binds MHC II.

MHC I

Found on all nucleated cells; presents internal antigens.

MHC II

Found on antigen-presenting cells.

Antigen-presenting cell

Cell that displays antigen on MHC II.

Neutrophils

Most abundant phagocytic white blood cells.

Macrophages

Large phagocytic cells in tissues.

Dendritic cells

Antigen-presenting cells that activate T cells.

Opsonization

Coating pathogen with antibody or C3b to enhance phagocytosis.

Complement

Blood proteins that assist immune defense.

Inflammation

Localized response causing redness, heat, swelling, pain.

Histamine

Inflammatory mediator causing vasodilation.

Autoimmune disorder

Immune system attacks self antigens.

Immunoglobulin G (IgG)

Only antibody class that crosses placenta.

Primary immune response

First exposure response; slower and weaker.

Secondary immune response

Later exposure response; faster and stronger.

Antibodies

Neutralize toxins, agglutinate pathogens, opsonize targets.

Antibodies do not

Directly kill bacteria.

Kirby-Bauer test

Disk diffusion test for antibiotic sensitivity.

MIC

Minimum inhibitory concentration preventing visible growth.

Binary fission

Asexual bacterial cell division producing two cells.

Lag phase

Growth phase with metabolic activity but no division.

Log phase

Rapid exponential growth phase.

Stationary phase

Growth rate equals death rate.

Death phase

Population declines.