Spontaneously occurring staphylococcal mutants resistant to clinically achievable concentrations of ciprofloxacin and temafloxacin.
The frequency of spontaneously occurring mutants resistant to 0.5, 1, 2, 4 and 8 micrograms of temafloxacin or ciprofloxacin per milliliter was documented with four Staphylococcus aureus and four Staphylococcus epidermidis strains. Resistant mutants were recovered at two- to four-fold the MIC of either drug, and they displayed cross-resistance to other fluoroquinolones. Resistance to temafloxacin occurred at frequencies lower than those observed with equal concentrations of ciprofloxacin. Resistance to greater than four-fold the MIC of either drug was not detected (frequencies less than 10(-10).
Barry
A L
AL
Clinical Microbiology Institute, Tualatin, Oregon 97062.
Pfaller
M A
MA
Fuchs
P C
PC
D000890:Anti-Infective Agents; D002939:Ciprofloxacin / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D024841:Fluoroquinolones; D008826:Microbial Sensitivity Tests; D009154:Mutation; D015363:Quinolones / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics; D013212:Staphylococcus epidermidis / Q000187:drug effects* / Q000235:genetics
D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D015363:Quinolones; C054745:temafloxacin; D002939:Ciprofloxacin