Question

fill in the blank question
based on the zones of inhibition for the three antibiotic discs indicated by the arrows, this image of a kirby - bauer test shows that the bacteria are resistant to the antibiotic
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(image: a petri dish with antibiotic discs labeled vancomycin, tetracycline, polymyxin b, and others, with arrows pointing to some discs. text alternative: (c) ser burbaker/mcgraw hill)

Explanation:

Step1: Analyze Kirby - Bauer Test

In the Kirby - Bauer test, a zone of inhibition around an antibiotic disc indicates susceptibility, while no (or very small) zone indicates resistance.

Step2: Observe Zones for Each Antibiotic

• For Vancomycin: There is a visible zone of inhibition (dark area around the disc), so bacteria are susceptible.
• For Tetracycline: There is a visible zone of inhibition, so bacteria are susceptible.
• For Polymyxin B: There is no (or negligible) zone of inhibition around the disc, meaning the bacteria are resistant to Polymyxin B.

Answer:

Polymyxin B