MSA and BEA Media Quizs

Detection in Voges Proskauer (VP) Test

• Detects Gram POSITIVE bacterium that uses lactic acid pathway for fermentation

• Detects Gram NEGATIVE bacterium that uses butylene glycol pathway for fermentation glucose gets converted to 2,3 butanediol and acetoin

• Detects Gram NEGATIVE bacterium that uses alcoholic fermentation pathway

• Detects Gram POSITIVE bacterium that uses butylene glycol pathway for fermentation

Positive result in Voges-Proskauer test

• It will be yellow if it uses the mixed acid fermentation pathway.

• It will be red if it uses the butylene glycol pathway for fermentation. (Correct Answer)

• It will remain colorless regardless of the fermentation pathway.

• It will be green if it uses the alcohol fermentation pathway.

No clotting in coagulase test

• Positive

• Negative

• Inconclusive

• Invalid

Determining motility of gram-negative bacterium

• Checking the turbidity of the medium. Turbid = Motility (+), Not turbid = Motility (-).

• Observing the color change in the medium. Color change = Motility (+), No color change = Motility (-).

• Measuring the pH of the medium. Acidic pH = Motility (+), Neutral pH = Motility (-).

• Counting the number of colonies. More colonies = Motility (+), Fewer colonies = Motility (-).

Mixed acid pathways that produce stable acids

• Lactic acid, acetic acid, formic acid

• Citric acid, malic acid, tartaric acid

• Butyric acid, propionic acid, isobutyric acid

• Oxalic acid, benzoic acid, salicylic acid

Positive result in Simmons's Citrate Test

• Escherichia coli

• Enterobacter

• Staphylococcus aureus

• Salmonella typhimurium

Purpose of the oxidase test

• To determine if the bacterium can ferment carbohydrates.

• To check if the bacterium is an obligate aerobe that has cytochrome c producing the enzyme.

• To assess the bacterium's ability to produce hydrogen sulfide.

• To evaluate the bacterium's resistance to antibiotics.

Yellow butt and red slant in TSI test

• Glucose was fermented.

• Lactose was fermented.

• Sucrose was fermented.

• No fermentation occurred.

Positive MSA Test

• Mannitol sugar that can be fermented by some Gram + bacteria leading to acid production and yellow colonies.

• A test that indicates the presence of Gram - bacteria in a sample.

• A method to identify the presence of glucose in a culture medium.

• A procedure to determine the antibiotic resistance of bacteria.

Yellow bottom and slant in TSI test

• Yellow butt and slant (acid production): lactose and/or sucrose were fermented.

• Yellow butt and red slant (alkaline production): no fermentation occurred.

• Red butt and yellow slant (alkaline production): only glucose was fermented.

• Red butt and slant (no acid production): no fermentation occurred.