Variations in bacitracin susceptibility observed in Staphylococcus and Micrococcus species.
Bacitracin susceptibility was evaluated as a laboratory method to differentiate staphylococci from micrococci. A total of 317 staphylococcal isolates and 108 micrococcal isolates were each tested for susceptibility to bacitracin by a disk-diffusion method using disks of three different potencies (0.04, 2.0, and 10.0 U) and a broth dilution method to obtain MICs. When a growth inhibition zone diameter breakpoint of greater than 10 mm was used to establish susceptibility with a 0.04-U disk, all micrococci were bacitracin susceptible and 94.6% of the staphylococci were resistant. Testing with disks of higher potency did not improve the specificity of the disk-diffusion method.
Baker
J S
JS
Hackett
M F
MF
Simard
D J
DJ
D001414:Bacitracin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D008826:Microbial Sensitivity Tests; D008837:Micrococcus / Q000145:classification / Q000187:drug effects*; D013210:Staphylococcus / Q000145:classification / Q000187:drug effects*
D001414:Bacitracin