Question

_______ biochemical test is not used for identification of Salmonella.

• A. Urea broth
• B. Indole Test
• C. MR-VP medium
• D. Catalase test

Hint:

Diagnostic schemes for enterics rely on specific biochemical profiles (like Triple Sugar Iron, Urease, and Indole) rather than general bacterial characteristics like catalase production.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Biochemical testing panels (such as IMViC and specific metabolic assays) are used to differentiate and identify closely related enteric bacteria.

Step 2: Detailed Explanation:
- Salmonella species have specific biochemical profiles: they are urease-negative (tested using Urea broth), indole-negative (tested using Indole test), Methyl Red-positive, and Voges-Proskauer-negative (using MR-VP medium). These tests are critical diagnostic steps used to identify the genus.
- The catalase test is a general test that determines whether an organism produces the catalase enzyme.
Nearly all members of the Enterobacteriaceae family (including Salmonella) are catalase-positive, meaning this test is not specific enough to help identify or differentiate Salmonella.

Step 3: Final Answer:
Therefore, the catalase test is not a specific diagnostic biochemical test used to identify Salmonella.