Quick Review Cards for Medical Laboratory Science

Disk Diffusion Susceptibility Method

(Kirby Bauer)continued

Clinical Microbiology Review 228

Reporting

Quality control

CFU = colony-forming units; CLSI = Clinical and Laboratory Standards Institute.

Resistant, intermediate, or susceptible based on zone of inhibition in mm. Refer to CLSI interpretive

tables.

Test QC strains ofE. coli, S. aureus, P. aeruginosa, Enterococcus faecalis for 20–30 consecutive days. If

results are acceptable, frequency can be reduced to weekly.