Comparison of a highly automated 5-h susceptibility testing system, the Cobas-Bact, with two reference methods: Kirby-Bauer disk diffusion and broth microdilution.
The results of susceptibility tests performed with the Cobas-Bact system were compared with those of the Kirby-Bauer disk diffusion and the broth microdilution methods. The evaluation included tests with 24 antibiotics against 250 isolates of the family Enterobacteriaceae and 13 antibiotics against 100 gram-positive cocci. Complete agreements between the Cobas-Bact and Kirby-Bauer methods were 82.8 and 84.5% for gram-positive cocci and gram-negative bacilli, respectively. Agreements between the Cobas-Bact and broth microdilution methods were 76.7% for gram-positive cocci and 84.8% for gram-negative bacilli. Complete agreements between the Kirby-Bauer and broth microdilution methods were 87.0% for gram-positive cocci and 92.2% for gram-negative bacilli. Despite generally satisfactory results with most organism-antibiotic combinations tested, additional modifications of the Cobas-Bact system are required to reduce the number of major and very major discrepancies, as well as to permit testing of Pseudomonas spp. and other gram-negative nonfermentative bacilli.
Washington University School of Medicine, Saint Louis, Missouri.
P R
PR
Murray
A C
AC
Niles
R L
RL
Heeren
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004755:Enterobacteriaceae / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D008826:Microbial Sensitivity Tests / Q000379:methods*; D012984:Software
D000900:Anti-Bacterial Agents