First Report of Coexistence of bla SFO-1 and bla NDM-1 β-Lactamase Genes as Well as Colistin Resistance Gene mcr-9 in a Transferrable Plasmid of a Clinical Isolate of Enterobacter hormaechei

Wenxiu Ai; Ying Zhou; Bingjie Wang; Qing Zhan; Longhua Hu; Yanlei Xu; Yinjuan Guo; Liangxing Wang; Fangyou Yu; Xiaolong Li

doi:10.3389/fmicb.2021.676113

First Report of Coexistence of bla _SFO-1 and bla _NDM-1 β-Lactamase Genes as Well as Colistin Resistance Gene mcr-9 in a Transferrable Plasmid of a Clinical Isolate of Enterobacter hormaechei

Front Microbiol. 2021 Jun 18:12:676113. doi: 10.3389/fmicb.2021.676113. eCollection 2021.

Authors

Wenxiu Ai¹, Ying Zhou^{2

3}, Bingjie Wang^{2

3}, Qing Zhan^{2

3}, Longhua Hu⁴, Yanlei Xu^{2

3}, Yinjuan Guo^{2

3}, Liangxing Wang¹, Fangyou Yu^{2

3}, Xiaolong Li⁵

Affiliations

¹ Department of Respiratory Medicine, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
² Department of Clinical Laboratory Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China.
³ Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China.
⁴ Jiangxi Provincial Key Laboratory of Medicine, Clinical Laboratory of the Second Affiliated Hospital of Nanchang University, Nanchang, China.
⁵ Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.

Abstract

Many antimicrobial resistance genes usually located on transferable plasmids are responsible for multiple antimicrobial resistance among multidrug-resistant (MDR) Gram-negative bacteria. The aim of this study is to characterize a carbapenemase-producing Enterobacter hormaechei 1575 isolate from the blood sample in a tertiary hospital in Wuhan, Hubei Province, China. Antimicrobial susceptibility test showed that 1575 was an MDR isolate. The whole genome sequencing (WGS) and comparative genomics were used to deeply analyze the molecular information of the 1575 and to explore the location and structure of antibiotic resistance genes. The three key resistance genes (bla _SFO-1, bla _NDM-1, and mcr-9) were verified by PCR, and the amplicons were subsequently sequenced. Moreover, the conjugation assay was also performed to determine the transferability of those resistance genes. Plasmid files were determined by the S1 nuclease pulsed-field gel electrophoresis (S1-PFGE). WGS revealed that p1575-1 plasmid was a conjugative plasmid that possessed the rare coexistence of bla _SFO-1, bla _NDM-1, and mcr-9 genes and complete conjugative systems. And p1575-1 belonged to the plasmid incompatibility group IncHI2 and multilocus sequence typing ST102. Meanwhile, the pMLST type of p1575-1 was IncHI2-ST1. Conjugation assay proved that the MDR p1575-1 plasmid could be transferred to other recipients. S1-PFGE confirmed the location of plasmid with molecular weight of 342,447 bp. All these three resistant genes were flanked by various mobile elements, indicating that the bla _SFO-1, bla _NDM-1, and mcr-9 could be transferred not only by the p1575-1 plasmid but also by these mobile elements. Taken together, we report for the first time the coexistence of bla _SFO-1, bla _NDM-1, and mcr-9 on a transferable plasmid in a MDR clinical isolate E. hormaechei, which indicates the possibility of horizontal transfer of antibiotic resistance genes.

Keywords: Enterobacter hormaechei; IncHI2; WGS; blaNDM–1; blaSFO–1; mcr-9; mobile elements; plasmid.