Question

Match List-I with List-II
List-I (Selective isoaltion/ growth medium for pathogens/ Hygiene microbes) :
(A). Ottaviani Agosti Medium
(B). Deoxycholate agar
(C). Xylose lysine deoxycholate agar
(D). Yeast extarct glucose Chlorempenicol agar
List-II (Name of the bacterial pathogens/ hygiene microbes) :
(I). Yeast and molds
(II). Listeria monocytogenes
(III). Shigella spp
(IV). Salmonella spp
Choose the correct answer from the options given below:

• (A) - (I), (B) - (II), (C) - (III), (D) - (IV)
• (A) - (II), (B) - (III), (C) - (IV), (D) - (I)
• (A) - (III), (B) - (IV), (C) - (I), (D) - (II)
• (A) - (IV), (B) - (I), (C) - (II), (D) - (III)

Hint:

Remember that the presence of an antibiotic like chloramphenicol (in YGC agar) is designed to inhibit bacteria, making it a standard choice for enumerating yeasts and molds (D-I).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Selective media contain specific chemical inhibitors that prevent the growth of unwanted background microbes while permitting the selective isolation and growth of target pathogens.

Step 2: Detailed Explanation:
Let us match the media in List-I with their target organisms in List-II:

• (A) Ottaviani Agosti Medium (ALOA): A selective chromogenic medium designed specifically for the isolation and differentiation of (II) Listeria monocytogenes. Thus, \(A \rightarrow \text{II}\).

• (B) Deoxycholate agar: A selective and differential medium used for the isolation of enterics, particularly (III) Shigella spp and Coliforms. Thus, \(B \rightarrow \text{III}\).

• (C) Xylose Lysine Deoxycholate (XLD) agar: A highly selective medium used for the isolation of (IV) Salmonella spp (which form red colonies with black centers due to \(\text{H}_2\text{S}\) production). Thus, \(C \rightarrow \text{IV}\).

• (D) Yeast extract glucose Chloramphenicol agar (YGC): Contains chloramphenicol to suppress bacterial growth, allowing the selective enumeration of (I) Yeast and molds. Thus, \(D \rightarrow \text{I}\).
This results in the matching sequence: (A)-(II), (B)-(III), (C)-(IV), (D)-(I).

Step 3: Final Answer
The correct matching sequence is (A) - (II), (B) - (III), (C) - (IV), (D) - (I).