Detection of aac(6′)-Ib-cr in KPC-producing Klebsiella pneumoniae isolates from Tel Aviv, Israel

Objectives: We aimed to evaluate the occurrence and characteristics of plasmid-mediated quinolone resistance (PMQR) genes in KPC-producing (KPC-P) Klebsiella pneumoniae (Kpn) isolates in Tel Aviv Medical Center, Israel. Methods: Forty-seven KPC-P Kpn isolates were studied. Antibiotic susceptibilities were determined by Vitek 2, Etest or agar dilution. beta-Lactamases and PMOR determinants were detected by PCR. For plasmid characterization, transformation, transconjugation, restriction mapping and Southern blot analysis were performed . Results: Six out of 47 (13%) KPC-P isolates carried aac(6')-Ib-cr. Acquisition of aac(6')-Ib-cr-encoding plasmids increased the MIC of ciprofloxacin by 2-fold. In five of six KPC-P isolates, aac(6')-Ib-cr and bla(KPC-2) were encoded on the same plasmid. Conclusions: The most prevalent PMQR gene in the studied KPC-P X pneumoniae isolates is aac(6')-Ib-cr. The co-existence of PMQR genes with KPC on the same plasmid poses a serious epidemiological, clinical and public-health threat.