Question

What is a zone of inhibition?

A. The area around the Bunsen burner that is considered sterile
B. The area around the antibiotic disk in which bacteria cannot grow
C. The area between two antagonistic antibiotics
D. The area in which antibiotics are inhibited from killing bacteria

Answer 1

A zone of inhibition is the clear area around an antimicrobial drug-impregnated disk on an agar plate, indicating where bacterial growth has been prevented due to the drug's effectiveness.Hence, option B is the correct answer.

Step-by-step explanation:

A zone of inhibition is a clear area around a filter paper disk that is impregnated with an antimicrobial drug on an agar plate covered with bacteria. This clear zone indicates that bacterial growth has been inhibited due to the antimicrobial drug. The size of the zone of inhibition depends on factors like drug solubility, rate of drug diffusion through agar, and the drug's concentration. In the Kirby-Bauer disk diffusion assay, these clear zones around the disks reveal which antibiotics the bacteria are susceptible or resistant to. Notably, it should be understood that larger zones of inhibition generally suggest a more effective antibiotic, but this cannot determine whether the activity is bactericidal or bacteriostatic without further testing.