How is a gelatin hydrolysis test performed on Enterobacteriaceae?

How is a gelatin hydrolysis test performed on Enterobacteriaceae?

• A. By assessing color change in the medium
• B. By measuring the pH of the medium
• C. By observing the consistency of the medium after incubation
• D. By checking for gas production

Answer: (C)

The gelatin hydrolysis test is specifically designed to determine the organism's ability to produce gelatinase, an enzyme that hydrolyzes gelatin into smaller peptides and amino acids. This enzymatic activity can be assessed by observing the consistency of the medium after incubation. When gelatin is hydrolyzed, the medium transitions from a solid or semi-solid state to a more liquid form, indicating positive gelatinase activity. Therefore, after incubating the test tube containing gelatin, one would examine whether the medium remains solid or becomes liquefied. This observation directly reflects the organism's ability to hydrolyze gelatin. The other methods mentioned do not apply to the gelatin hydrolysis test, as there are no color changes indicating positive or negative reactions, pH measurements are not relevant to assessing gelatin hydrolysis, and gas production is not a characteristic observed in this specific test. Thus, observing the consistency of the medium after incubation is the most accurate and relevant method for performing the gelatin hydrolysis test on Enterobacteriaceae.

The gelatin hydrolysis test is specifically designed to determine the organism's ability to produce gelatinase, an enzyme that hydrolyzes gelatin into smaller peptides and amino acids. This enzymatic activity can be assessed by observing the consistency of the medium after incubation.

When gelatin is hydrolyzed, the medium transitions from a solid or semi-solid state to a more liquid form, indicating positive gelatinase activity. Therefore, after incubating the test tube containing gelatin, one would examine whether the medium remains solid or becomes liquefied. This observation directly reflects the organism's ability to hydrolyze gelatin.

The other methods mentioned do not apply to the gelatin hydrolysis test, as there are no color changes indicating positive or negative reactions, pH measurements are not relevant to assessing gelatin hydrolysis, and gas production is not a characteristic observed in this specific test. Thus, observing the consistency of the medium after incubation is the most accurate and relevant method for performing the gelatin hydrolysis test on Enterobacteriaceae.