Microbiology Lab Review

Vocabulary flashcards for microbiology lab review.

MacConkey Agar

Selective and differential medium used to differentiate coliforms from the Enterobacteriaceae family; selective for G- bacteria and differential for lactose fermentation (pink colonies indicate positive result).

BGLB Test (Brilliant Green Lactose Bile Broth)

Selective and differential medium used to identify the presence of coliforms; selective against G+ bacteria and differential for lactose fermentation with gas production.

EMB Agar (Eosin Methylene Blue)

Selective and differential medium used to differentiate possible vs probable fecal coliforms; selective against G+ bacteria and differential for lactose and sucrose fermentation.

O/F Glucose Test

Medium used to identify whether an organism is capable of oxidation (aerobic) or fermentation (anaerobic) or both using glucose.

Phenol Red Test

Differential test to observe if microbes ferment carbohydrates (glucose, lactose, sucrose), indicated by a color change in the phenol red pH indicator and/or gas production in the Durham tube.

Phenylalanine Deaminase Test

Differential test to detect organisms that produce phenylalanine deaminase, resulting in the production of phenylpyruvic acid which reacts with ferric chloride to produce a green color.

DNase Test

Differential test to detect organisms that produce DNase, which depolymerizes DNA, creating a halo around the growth on DNA agar.

Bile Esculin Test

Selective and differential medium used to detect organisms capable of utilizing esculin in the presence of bile, particularly Enterococcus. Positive results shown by a dark brown color.

Lysine Iron Agar (LIA)

Differential medium used to detect lysine deaminase, lysine decarboxylase, glucose fermentation, and hydrogen sulfide gas production.

Urease Test

Differential test to detect organisms capable of producing urease, which hydrolyzes urea to ammonia, resulting in a pH increase and a bright pink color change in the presence of phenol red.

Decarboxylase Test

Test designed to detect the presence of the inducible lysine decarboxylase enzyme

Starch Hydrolysis Test

Differential test to identify organisms capable of breaking down starch using amylase and oligo 1,6-glucosidase, indicated by a clear halo around the growth on starch agar after iodine addition.

Citrate Test

Differential test to detect organisms capable of utilizing citrate as the sole carbon source, resulting in a pH increase and a blue color change in the presence of bromthymol blue.

Catalase Test

Test to identify organisms that produce catalase, which detoxifies hydrogen peroxide into water and oxygen. Bubbles indicate a positive result.

Gelatinase Test

Test to identify organisms which secrete gelatinase which breaks gelatin (collagen) down into amino acids

Nitrate Reduction Test

Differential test to identify organisms that use nitrate as a terminal electron acceptor in anaerobic respiration, reducing it to nitrite, nitric oxide, nitrous oxide, or nitrogen gas.

MR-VP Test

Test to determine if microbe is capable of mixed acid fermentation (MR) OR 2,3 butanediol fermentation (VP)

SIM Test

Differential medium used to test for hydrogen sulfide production, indole production, and motility.

Triple Sugar Iron (TSI) Agar

Differential medium used to detect glucose, lactose, and/or sucrose fermentation; thiosulfate reduction; and gas production.

Blood Agar Test

Differential medium used to differentiate bacteria based on their hemolytic ability (alpha, beta, or gamma hemolysis).

Hektoen Enteric Agar (HEA)

Selective and differential medium used to identify Shigella and Salmonella from coliforms.

Mannitol Salt Agar (MSA)

Selective and differential medium used to differentiate pathogenic Staphylococcus aureus from non-pathogenic Staphylococci.

Simple Stain

A staining process utilizing only one stain to allow easy visualization of microorganisms

Differential Stain

A staining process utilizing more than one stain to differentiate between organisms or cellular structures.

Negative Stain

A staining method using a negative auxochrome/acidic stain that repels the cell.