Question

Match List I with List II
List I (Microorganisms):
A. Escherichia coli
B. Enterobacter aerogenes
C. Salmonella
D. Proteus
List II (Characteristics):
I. Urease enzyme activity
II. H2S production
III. IMViC ++--
IV. IMViC --++
V. Hippurase enzyme activity
Choose the correct answer from the options given below:

• A. A - I, B - II, C - III, D - IV
• B. A - II, B - III, C - IV, D - V
• C. A - III, B - IV, C - II, D - I
• D. A - IV, B - V, C - I, D - II

Hint:

Remember the classic contrast: E. coli is IMViC ++--, while Enterobacter aerogenes is IMViC --++. This alone is often sufficient to identify the correct matching option.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Differentiating Enterobacteriaceae and related Gram-negative rods relies on standard biochemical profiles, including the IMViC series (Indole, Methyl Red, Voges-Proskauer, Citrate), hydrogen sulfide ($H_2S$) production, and urease activity.

Step 2: Detailed Explanation:
Let us match each microorganism in List I with its signature characteristic in List II:
- A. Escherichia coli: This species is a classic fecal coliform that displays an IMViC profile of positive Indole, positive Methyl Red, negative Voges-Proskauer, and negative Citrate utilization, represented as ++-- (III).
- B. Enterobacter aerogenes: This environmental coliform possesses a metabolic profile opposite to E. coli, showing negative Indole, negative Methyl Red, positive Voges-Proskauer, and positive Citrate utilization, represented as --++ (IV).
- C. Salmonella: Most Salmonella species are known for producing hydrogen sulfide ($H_2S$) gas from sulfur-containing amino acids, resulting in black precipitates on triple sugar iron (TSI) agar, matching with H2S production (II).
- D. Proteus: Proteus species are highly distinct because they produce a rapid, active urease enzyme that hydrolyzes urea to ammonia, turning urea agar bright pink, matching with Urease enzyme activity (I).
Combining these matches gives us: A-III, B-IV, C-II, D-I.

Step 3: Final Answer
The correct option is (C).