Comparison of a veterinary breakpoint minimal inhibitory concentration system and a standardized disk agar diffusion procedure for antimicrobic susceptibility testing.
The correlation between the antimicrobic standard disk agar diffusion procedure and a veterinary antimicrobic breakpoint minimal inhibitory concentration system was evaluated. Bacterial isolates representing 5 different genera were tested against 15 antimicrobics. There were 3,795 tests performed; 77.3% of the test results were in agreement, 22.6% were in disagreement. Thirty-one percent of the conflicting results were due to the organism being intermediate on the standard disk agar diffusion procedure. Results suggest that the breakpoint system needs more than 1 antimicrobic dilution per antimicrobic, or a change in some of the single dilutions in the breakpoint system would eliminate some of these discrepancies. Another possibility would be to utilize more than 1 panel design, i.e., 1 for gram-positive organisms, 1 for gram-negative organisms, and 1 for fastidious organisms.
Watson
C K
CK
Veterinary Diagnostic and Investigational Laboratory, College of Veterinary Medicine, University of Georgia, Tifton 31794.
Cole
J R
JR
Pursell
A R
AR
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D008826:Microbial Sensitivity Tests / Q000662:veterinary*
D000900:Anti-Bacterial Agents