Culture Media & Culture Methods - Vocabulary Flashcards

A set of vocabulary-style flashcards covering key terms related to culture media, media types, selective/differential media, and culture methods from the lecture notes.

Culture media

Substances used to grow microorganisms for identification, study, and isolation.

Isolation

Process of obtaining a pure culture by separating a single organism on culture media.

Colony

Macroscopically visible population of bacteria originating from a single cell.

Solid medium

Culture medium that solidifies (usually with agar) to form discrete colonies.

Liquid medium

Culture medium without agar, used for growth and inoculum preparation.

Semi-solid medium

Medium with reduced agar (about 0.5%) used for motility testing and other assays.

Agar

Solidifying agent from seaweed; non-nutritive; melts at 98°C and sets at 42°C; 2% commonly used.

Frau Hesse

Person credited with introducing agar for solid culture media.

2% agar

Concentration of agar used to prepare solid culture media.

Simple (basal) medium

Basic nutrient medium providing essential components for growth.

Nutrient broth (NB)

Liquid basal medium containing peptone, meat extract, and NaCl.

Nutrient agar (NA)

Solid form of NB with 2% agar for plate culture.

Complex medium

Medium with added ingredients whose exact composition is not fully defined.

Synthetic (defined) medium

Medium composed of pure chemical substances with known exact composition.

Enriched medium

Basal medium supplemented with nutrients (e.g., blood, serum, egg) for fastidious organisms.

Enrichment medium

Liquid or solid medium designed to enhance growth of a target organism from mixed cultures.

Selective medium

Medium containing inhibitors to suppress unwanted organisms while permitting the target organism to grow.

Indicator medium

Medium containing an indicator that changes color to reveal metabolic activity.

Differential medium

Medium that differentiates organisms by observable colony characteristics.

Sugar medium

Medium designed to assess sugar fermentation and acid production.

Transport medium

Medium that preserves viability of microorganisms during transport.

Aerobic medium

Medium that requires or provides oxygen for growth.

Anaerobic medium

Medium designed to exclude or minimize oxygen for anaerobes.

Blood agar

Solid medium with blood to observe hemolysis and growth patterns.

Chocolate agar

Heated blood agar that releases nutrients for fastidious organisms.

MacConkey’s medium

Selective and differential for Gram-negative bacteria; differentiates lactose fermenters.

TCBS (Thiosulfate-Citrate-Bile-Salts-Sucrose)

Selective/differential medium for Vibrio species.

Lowenstein-Jensen (LJ) medium

Selective medium for Mycobacterium tuberculosis.

Potassium tellurite medium

Selective medium for Corynebacterium diphtheriae; tellurite inhibits others.

Selenite F broth

Enrichment broth for isolation of Salmonella and Shigella from mixed cultures.

Alkaline Peptone Water

Enrichment broth favoring growth of Vibrio species.

Streak culture

Inoculation technique to obtain isolated colonies by streaking across an agar surface.

Lawn culture

Uniform surface growth of bacteria across the entire agar plate.

Stab culture

Inoculation by penetrating agar with a needle to study oxygen requirements and gelatin liquefaction.

Pour plate culture

Technique where melted agar is inoculated and poured into a plate to count colonies throughout the depth.

Liquid culture

Growth of organisms in a liquid medium; used for blood cultures and sterility testing.

Blood culture

Detection of bacteremia by growing organisms from blood samples in broth or bottles.

Sterility test

Test to ensure products or specimens are free from viable microorganisms.

Continuous culture

Culturing method where fresh medium is added to maintain growth (e.g., chemostat).

Lactose fermenter

Bacteria that ferment lactose, often producing pink colonies on MacConkey’s agar.

Non-lactose fermenter

Bacteria that do not ferment lactose; colonies are colorless or less distinct on MacConkey’s agar.

Hemolysis

Destruction of red blood cells observed on blood agar as alpha, beta, or gamma hemolysis.

Colony morphology

Visible characteristics of colonies (size, shape, color, edge) used for identification.