Inhibition zone

Question

Hi!

I did a Kirby-Bauer lab seeing antibiotic resistance in E.coli. I have measured the inhibition zones, but I am not sure how to confirm if it is large enough to be considered not resistant or somewhat resistant. Is there a calculation or big, general table for that?

Thanks in advance!

Answer 1

There is a table to which you will compare your zone of inhibition measurement. This should have been provided to you, but here is an example. https://bio.libretexts.org/Bookshelves/Ancillary_Materials/Laboratory_Experiments/Microbiology_Labs/Microbiology_Labs_I/09%3A_Kirby-Bauer_(Antibiotic_Sensitivity)

Compare your zone of inhibition to the zone size for the particular antibiotic you are surveying. Pay attention that the drug and dose are exactly alike. Some antibiotics have different criteria for different organisms, eg. zones for S. aureus and zones for other organisms.

Hope it helps, Connie