Infection and Drug Resistance (Sep 2019)
Characterization Of blaNDM-5-Positive Escherichia coli Prevalent In A University Hospital In Eastern China
Abstract
Pengfei Sun,1,2,* Wenying Xia,1,2,* Genyan Liu,1,2 Xu Huang,1,2 Chenjie Tang,1,2 Chengcheng Liu,1,2 Yuqiao Xu,1,2 Fang Ni,1,2 Yaning Mei,1,2 Shiyang Pan1,2 1Department of Laboratory Medicine, Jiangsu Province Hospital and Nanjing Medical University First Affiliated Hospital, Nanjing, People’s Republic of China; 2National Key Clinical Department of Laboratory Medicine, Nanjing, People’s Republic of China*These authors contributed equally to this workCorrespondence: Genyan LiuDepartment of Laboratory Medicine, Jiangsu Province Hospital, Guangzhou Street No. 300, Nanjing 210029, People’s Republic of ChinaTel +8625 6830 7332Fax +8625 8372 4440Email [email protected]: The emergence and spread of carbapenem-resistant Enterobacteriaceae deserves special concern worldwide. Unlike the epidemiological characteristics reported in other studies, we found that the production of New Delhi metallo-β-lactamase 5 was the main mechanism for the resistance of Escherichia coli to carbapenems.Methods: All carbapenem-resistant strains were collected from July 2017 to July 2018 of the First Affiliated Hospital of Nanjing Medical University. The presence of carbapenemase-encoding genes was detected using PCR and gene sequencing. Genetic relatedness of the blaNDM-5-positive E. coli strains was determined with PFGE and MLST. Susceptibility profiles were measured with broth microdilution method and E-test strips. Transferability features of blaNDM-5 gene were assessed by conjugation experiments, S1-PFGE, southern blotting and PCR-based replicon typing methods. The genetic structures surrounding blaNDM-5 were acquired by whole genome sequencing and PCR mapping.Results: Among the 28 carbapenem-resistant E. coli strains, 18 (64%) were verified as NDM-5 producers. The 18 blaNDM-5-positive E. coli strains showed high resistance to most antibiotics, but 100% were sensitive to colistin and tigecycline. In addition, the 18 blaNDM-5-positive E. coli strains belonged to eight STs, among which ST167, ST410 and ST101 were found to cause clonal spread in the hospital. Further studies found that the blaNDM-5 gene was located on an IncX3-type plasmid, and all plasmids harbored an IS3000-ΔISAba125-IS5-blaNDM-5-bleMBL-trpF-dsbC-IS26 structure.Conclusion: The clonal spread of blaNDM-5-positive E. coli strains and horizontal dissemination via the pNDM-MGR 194-like plasmids should draw more attention. Appropriate infection control operations should be performed to prevent the further spread of blaNDM-5.Keywords: Escherichia coli, carbapenem-resistant Enterobacteriaceae, New Delhi metallo-β-lactamase, blaNDM-5, IncX3 type plasmid
