Antimicrobial susceptibility testing by the Kirby-Bauer disc diffusion method.

Antimicrobial susceptibility testing by the disc diffusion method is discussed with emphasis on the need for standardization of methodology. The KirbyBauer method is currently widely used by clinical laboratories and best incor­ porates many of the features recommended by the World Health Organization. It is relatively simple from a technicological standpoint and accurate and reproducible so long as the methodology is followed with care. Modifications should be accepted only after full documentation of the effects on inhibition zone sizes.