Emergence of Proteus mirabilis HarboringblaKPC-2andqnrDin a Chinese Hospital

Abstract

ABSTRACTNineteen carbapenem-nonsusceptibleProteus mirabilisisolates were recovered from intensive care units in the Second Affiliated Hospital of Zhejiang University during a 3-month period. The isolates showed a high level of resistance against ciprofloxacin, in addition to their resistance against the carbapenems. Pulsed-field gel electrophoresis (PFGE) analysis showed that these isolates belonged to three clonal strains. PCRs and DNA sequence analysis of the carbapenemase and other β-lactamase genes indicated that all the isolates harbored theblaKPC-2gene. Twelve of 19 isolates harbored the plasmid-mediated quinolone resistance (PMQR) genes, both theqnrDandaac(6′)-Ib-crgenes. Eight representative isolates with high levels of quinolone resistance carried the similar mutation profiles of S83I ingyrA, E466D ingyrB, and S80I inparC. Reduced carbapenem susceptibility was transferred toEscherichia coli(EC600) in a conjugation experiment, while the quinolone resistance was not. DNA hybridization showed thatqnrDwas located on a plasmid of approximately 4.5 kb. In summary, large clonally related isolates of KPC-2-producingP. mirabilisemerged in a Chinese hospital, andqnrDwas detected in KPC-producingP. mirabilisfor the first time.