Mechanisms of quinolone resistance of carbapenem-resistant Enterobacteriaceae / 中国感染控制杂志

ABSTRACT

Objective To study the prevalence of plasmid-mediated quinolone resistance (PMQR) genes in carbapenem-resistant Enterobacteriaceae (CRE) and its resistance mechanism.Methods Clinically isolated CRE strains in a hospital from March 2015 to March 2018 were collected, then identified and performed antimicrobial susceptibility test by VITEK2 Compact analyzer, carriage of PMQR genes qnrA, qnrB, qnrS, qepA and acc (6') Ib-cr were determined by polymerase chain reaction (PCR) and sequencing, the horizontal transfer of PMQR genes were verified by plasmid conjugation test.Results Resistance rates of carbapenem-resistant Escherichia coli and carbapenem-resistant Klebsiella pneumoniae to quinolones were 100％ and 15.56％-33.33％ respectively.Detection rate of acc (6') Ib-cr gene was the highest (87.72％), followed by qnrB (77.19％) and qnrS (17.54％), 2 strains (3.51％) carried qnrA gene, qepA gene was not isolated, 84.21％ of strains harbored 2 or 3 PMQR genes.PMQR gene was transfected into all the 8 conjugated strains, but minimum inhibitory concentration value of quinolones didn't change significantly.Conclusion The detection rate of PMQR genes in CRE in this hospital is high, but there is a certain sensitivity to quinolones.