Comparison of Mutant Prevention Concentrations of Fluoroquinolones Against ESBL-Positive and ESBL-Negative Isolates from Orthopedic Patients.

The majority of isolates possess the extended-spectrum beta-lactamase (ESBL) enzymes. Therefore, can easily develop drug resistance. How to effectively overcome the problem of drug resistance in is still a research hotspot. This study aimed to compare the mutant prevention concentration (MPC) of ESBL-positive and ESBL-negative isolated from orthopedic patients, which may provide a basis for the effective use of drugs to control the enrichment of resistance mutants of . The MPC values of 55 isolates of ESBL-positive against 4 fluoroquinolones were 32 µg/mL for levofloxacin and gatifloxacin, 16 µg/mL for ciprofloxacin, and 4 µg/mL for gemifloxacin. The selection index value was 8 for levofloxacin and ciprofloxacin and 2 for gemifloxacin and gatifloxacin, respectively. For ESBL-negative isolates, the MPC values were 16 µg/mL for levofloxacin and ciprofloxacin, 4 µg/mL for gemifloxacin, and 32 µg/mL for gatifloxacin. The selection index value was 8 for levofloxacin and ciprofloxacin, 2 for gemifloxacin, and 4 for gatifloxacin. For the ESBL-positive , the %T>MIC order was gemifloxacin > levofloxacin > ciprofloxacin > gatifloxacin. For the ESBL-negative the %T>MIC order was levofloxacin > gemifloxacin > ciprofloxacin > gatifloxacin. The mutant-preventing ability of gatifloxacin and gemifloxacin was the strongest among the 4 fluoroquinolones. So gemifloxacin may be the first choice of drug to treat infection.