Characterization Of [bla.sub.NDM-5]-Positive Escherichia coli Prevalent In A University Hospital In Eastern China

• Published in: Infection and drug resistance 2019-09, p.3029
• Main Authors: Liu, Genyan, Tang, Chenjie, Liu, Chengcheng, Huang, Xu, Sun, Pengfei, Xia, Wenying, Xu, Yuqiao, Pan, Shiyang, Mei, Yaning, Ni, Fang
• Format: Article
• Language: English
• Subjects: Anopheles; Antibacterial agents; DNA sequencing; EDTA; Epidemiology; Escherichia coli; Genes; Genomes; Genomics; Imipenem; Medical schools; Meropenem; Microbial drug resistance; Tazobactam; Tigecycline
• ISSN: 1178-6973; 1178-6973

Purpose: 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-P-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 [bla.sub.NDM-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 [bla.SUB.NDM-5] gene were assessed by conjugation experiments, S1-PFGE, southern blotting and PCR-based replicon typing methods. The genetic structures surrounding [bla.sub.-NDM-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 [bla.sub.NDM-5]-positive E. coli strains showed high resistance to most antibiotics, but 100% were sensitive to colistin and tigecycline. In addition, the 18 [bla.SUB.NDM-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 [bla.SUB.NDM-5] gene was located on an IncX3-type plasmid, and all plasmids harbored an IS3000-AISAba125-IS5-[bla.sub.NDM-5]-bleMBL-trpF-dsbC-IS26 structure. Conclusion: The clonal spread of [bla.sub.NDM-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 [bla.SUB.NDM-5]. Keywords: Escherichia coli, carbapenem-resistant Enterobacteriaceae, New Delhi metallo-P-lactamase, [bla.sub.NDM-5], IncX3 type plasmid