Characterization of and mutations in ciprofloxacin-resistant isolates from Tehran hospitals in Iran.

BACKGROUND AND OBJECTIVES

, a major cause of several infectious diseases, has become a hazardous resistant pathogen. One of the factors contributing to quinolone resistance in is mutations occurring in and genes encoding the A subunits of type II and IV topoisomerases, respectively, in quinolone resistance determining regions (QRDR) of the bacterial chromosome.

MATERIALS AND METHODS

Thirty seven isolates from patients with burn wounds and 20 isolates from blood, urine and sputum specimen were collected. Minimum Inhibitory Concentrations (MICs) of ciprofloxacin were determined by agar diffusion assay. Subsequently, QRDRs regions of and were amplified from resistant isolates and were assessed for mutations involved in ciprofloxacin resistance after sequencing.

RESULTS

Nine isolates with MIC≥8 μg/ml had a mutation in (Thr83→Ile). Amongst these, seven isolates also had a mutation in (Ser87→ Leu or Trp) indicating that the prevalent mutation in is Thr83Ile and Ser87Leu/Trp in . No single mutation was observed.

CONCLUSION

It seems that mutations in are concomitant with mutations in which might lead to high-level ciprofloxacin resistance in isolates from patients with burn wounds and urinary tract infections.