Microbiology: Principles of Antimicrobial Therapy

A collection of vocabulary terms covering the principles, types, and mechanisms of antimicrobial drugs and microbial resistance.

Antimicrobial chemotherapy

The use of chemotherapeutic drugs to control infection.

Prophylaxis

The use of a drug to prevent imminent infection of a person at risk.

Antibiotics

Substances produced by the natural metabolic processes of some microorganisms that can inhibit or destroy other microorganisms.

Semisynthetic Drugs

Drugs that are chemically modified in the laboratory after being isolated from natural sources.

Synthetic Drugs

Drugs produced entirely by chemical reactions.

Narrow-Spectrum (Limited Spectrum)

Antimicrobials effective against a limited array of microbial types, for example, a drug effective mainly against gram-positive bacteria.

Broad-Spectrum (Extended Spectrum)

Antimicrobials effective against a wide variety of microbial types, for example, a drug effective against both gram-positive and gram-negative bacteria.

Kirby-Bauer technique

A method where the surface of an agar plate is spread with bacteria and small discs containing a prepared amount of antibiotic are placed on the plate to measure the zone of inhibition.

Minimum inhibitory concentration (MIC)

The smallest concentration (highest dilution) of a drug that visibly inhibits growth.

Therapeutic index (TI)

The ratio of the dose of the drug that is toxic to humans as compared to its minimum effective (therapeutic) dose; calculated as $TI = \frac{\text{toxic dose}}{\text{therapeutic dose}}$. outdoor

Selective toxicity

The property of a drug to kill or inhibit the actions or synthesis of molecules in microorganisms but not vertebrate cells.

Persisters

Microbes that slow or stop their metabolism so that they cannot be harmed by an antibiotic.

Resistance (R) factors

Plasmids containing antibiotic resistance genes that are naturally present in microbes and can be shared via horizontal transfer.

Beta-lactamases

Bacterial exoenzymes, also called penicillinases, that hydrolyze the beta-lactam ring structure of some penicillins and cephalosporins, rendering the drugs inactive.

Multidrug-resistant (MDR) pumps

Pumps possessed by many bacteria that actively transport drugs out of cells, conferring drug resistance on many gram-positive and gram-negative pathogens.

Quorum sensing pathways

Chemical communication systems in biofilms that can be interrupted as a strategy for treatment.

DRACO

An acronym for "double-stranded RNA-activated caspase oligomerizer," a breakthrough antiviral treatment currently being tested.

Probiotics

Preparations of live microorganisms fed to animals and humans to improve intestinal biota and replace microbes lost during antimicrobial therapy.

Prebiotics

Nutrients that encourage the growth of beneficial microbes, such as fructans that encourage the growth of Bifidobacterium.

Biota

Normal microbial colonists of healthy body surfaces that consist of harmless or beneficial bacteria.

Superinfection

A condition where microbes that were once small in number overgrow when normal resident biota are destroyed by broad-spectrum antimicrobials.