If the antibiotic disk is pushed deep into the agar during disk diffusion, what is the expected effect on the KB zone?

Prepare for the CAMLPR Microbiology Test. Utilize flashcards and engaging multiple-choice questions, each equipped with descriptions and explanations. Ready yourself for an excellent performance!

Multiple Choice

If the antibiotic disk is pushed deep into the agar during disk diffusion, what is the expected effect on the KB zone?

Disk diffusion results hinge on how the antibiotic diffuses from the disk into the surrounding agar. The zone of inhibition reflects the radius where the drug concentration is high enough to stop growth. When the disk is pressed deeper into the gel, more antibiotic can diffuse into the surrounding agar more effectively, enlarging the inhibition zone. This makes the organism appear susceptible even if it wouldn’t be in a true, surface-disk setup—a false susceptible result. To avoid this, the disk should rest on the agar surface without forcing it in, ensuring diffusion matches standard protocol.

Disk diffusion results hinge on how the antibiotic diffuses from the disk into the surrounding agar. The zone of inhibition reflects the radius where the drug concentration is high enough to stop growth. When the disk is pressed deeper into the gel, more antibiotic can diffuse into the surrounding agar more effectively, enlarging the inhibition zone. This makes the organism appear susceptible even if it wouldn’t be in a true, surface-disk setup—a false susceptible result. To avoid this, the disk should rest on the agar surface without forcing it in, ensuring diffusion matches standard protocol.

More practice questions