Kirby Bauer Test

Question

Hi!

What are some error sources for the Kirby Bauer test for antibiotic sensitivity?

Thanks!

Answer 1

The most common errors I have encountered are:

1. poorly inoculated plate so that the lawn of bacteria is incomplete or contaminated
2. incorrectly applied antibiotic disc--it falls off or has been moved around the plate so that the zone is not circular
3. mis-measurement of the zone of inhibition. The zone is the diameter in millimeters.
4. misreading the chart by confusing the greater than (>)and less than (,<) symbols.
5. using the zone chart for the wrong antibiotic
6. using the zone chart for the correct antibiotic, but for the wrong organism.

Connie