Unknown Exam Prep

What is the purpose of Motility Medium with TTC?

Detects bacterial movement.

What does a positive result in Motility Medium look like?

Diffuse red growth spreads from the stab line.

What indicates the presence of oxygen in Fluid Thioglycollate Medium?

Resazurin turns pink (oxygen present) or remains colorless (oxygen absent).

What does a facultative anaerobe’s growth pattern look like in Fluid Thioglycollate Medium?

Grows throughout, densest at the top.

What is indicated by a yellow change in Carbohydrate Fermentation tests?

Acid production from fermentation.

What does a positive result in Gelatin Hydrolysis look like?

Gelatin medium liquefies after refrigeration.

What principle does Urea Hydrolysis rely on to indicate a positive result?

Urease breaks down urea into ammonia, raising pH and turning the medium pink.

How is a positive catalase test identified?

Immediate bubbles when hydrogen peroxide is added.

What color change indicates a positive result in citrate utilization?

Medium turns blue.

What does a red color after adding reagents A and B indicate in the Nitrate Reduction test?

Positive for nitrate reduction to nitrite.

What color change indicates a positive result in the Methyl Red test?

Red color at pH ≤ 4.4.

What does a positive result in Voges-Proskauer indicate?

Red color develops on the surface after adding VP reagents.

What does the formation of a cherry-red ring in the Indole test indicate?

Positive for tryptophanase enzyme production.

What result indicates hydrogen sulfide production in Triple Sugar Iron Agar?

A black precipitate appears in the agar butt.

What does a green color develop in Phenylalanine Deamination indicate?

Presence of phenylalanine deaminase enzyme.

What will a positive Lysine Decarboxylase test result look like?

Medium turns purple after initial yellowing.

How is a positive Ornithine Decarboxylase test identified?

Medium turns purple after initial yellowing.