Low prevalence of mobilized resistance genes blaNDM, mcr-1, and tet(X4) in Escherichia coli from a hospital in China

Lin Sun; Guo-Zhuang Sun; Yue Jiang; Cai-Yue Mei; Zhen-Yu Wang; Han-Yun Wang; Gui-Mei Kong; Xinan Jiao; Jing Wang

doi:10.3389/fmicb.2023.1181940

Low prevalence of mobilized resistance genes bla_NDM, mcr-1, and tet(X4) in Escherichia coli from a hospital in China

Front Microbiol. 2023 May 19:14:1181940. doi: 10.3389/fmicb.2023.1181940. eCollection 2023.

Authors

Lin Sun^#^{1

2}, Guo-Zhuang Sun^#³, Yue Jiang^#^{1

2}, Cai-Yue Mei¹, Zhen-Yu Wang^{1

2}, Han-Yun Wang^{1

2}, Gui-Mei Kong⁴, Xinan Jiao^{1

2}, Jing Wang^{1

2}

Affiliations

¹ Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China.
² Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou, China.
³ Department of Clinical Laboratory, Xuyi People's Hospital, Huai'an, China.
⁴ Medical School of Yangzhou University, Yangzhou University, Yangzhou, China.

^# Contributed equally.

Abstract

The emergence and spread of carbapenemase genes, colistin resistance genes mcr-1, and tigecycline resistance gene tet(X) represent a significant threat to clinical therapy and public health. In this study, we investigated the presence of carbapenemase genes, mcr-1, and tet(X) in 298 Escherichia coli strains obtained from a teaching hospital in China. In total, eight (2.68%), six (2.01%), and one (0.34%) E. coli isolates carried bla_NDM, mcr-1, and tet(X4), respectively. The bla_NDM gene was located on IncX3 (n = 4), F2:A-:B- (n = 3), and F2:A1:B1 (n = 1) plasmids, with high similarity to multiple plasmids belonging to the same incompatibility type from Enterobacteriaceae. Six MCR-producing strains contained mcr-1-carrying IncI2 plasmids, organized similarly to other mcr-1-bearing IncI2 plasmids from animals in China. The bla_{CTX-M-55/64/132/199} gene located within a typical transposition unit (ISEcp1-bla_CTX-M-orf477Δ) was inserted near dnaJ to generate 5-bp direct repeats in four mcr-1-positive plasmids. The tet(X) and another four resistance genes [aadA2, tet(A), floR, and Δlnu(F)] were co-located on an IncX1 plasmid, highly similar to other tet(X4)-carrying IncX1 plasmids from Escherichia and Klebsiella of animal or food origin, except that the conjugative transfer region of IncX1 plasmids was absent in our plasmid. Although a low prevalence of bla_NDM, mcr-1, and tet(X) was observed in E. coli from patients in this study, their dissemination associated with some successful pandemic plasmids is of great concern. The continued surveillance of these crucial resistance genes in patients should be strengthened.

Keywords: carbapenem; colistin; patients; plasmid; tigecycline.

Grants and funding

This study was supported by the fifth phase of the 333 Project Scientific Research Project in Jiangsu Province (BRA2020002), the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD), and the 111 Project (D18007).