Selection of a fluoroquinolone-class disk for susceptibility tests.
A study was conducted to select a fluoroquinolone disk that could be used to represent other members of the fluoroquinolone class of drugs for routine susceptibility testing in the laboratory. Eight different fluoroquinolone agents were tested by disk diffusion and broth microdilution methods using 185 bacterial isolates, including 60 Enterobacteriaceae, 50 Pseudomonas species, 45 other gram-negative bacilli, and 30 Staphylococcus aureus. False-susceptible and false-resistant test results occurred at rates of 0-10% when disks containing different agents were tested against this unusually resistant collection of isolates. Much lower error rates would be expected with the type of microorganisms routinely encountered in clinical laboratories. Pefloxacin, enoxacin, or ciprofloxacin disks were not useful as class representatives. However, amifloxacin, lomefloxacin, ofloxacin, temafloxacin, or fleroxacin disks could be used to represent the other fluoroquinolones for routine susceptibility testing with a minimal chance of incurring serious errors.
Clinical Microbiology Institut, Tualatin, Oregon 97062.
A L
AL
Barry
P C
PC
Fuchs
D000890:Anti-Infective Agents / Q000494:pharmacology*; D024841:Fluoroquinolones; D008826:Microbial Sensitivity Tests / Q000379:methods; D015363:Quinolones / Q000494:pharmacology
D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D015363:Quinolones; C054745:temafloxacin; C053091:lomefloxacin