Genomic characterization of a carbapenem-resistant Citrobacter freundii cocarrying blaKPC-2 and blaNDM-1

Ying Li; Chengju Fang; Yichuan Qiu; Xiaoyi Dai; Luhua Zhang

doi:10.1016/j.jgar.2022.04.014

Genomic characterization of a carbapenem-resistant Citrobacter freundii cocarrying bla_KPC-2 and bla_NDM-1

J Glob Antimicrob Resist. 2022 Jun:29:289-292. doi: 10.1016/j.jgar.2022.04.014. Epub 2022 Apr 27.

Authors

Ying Li¹, Chengju Fang¹, Yichuan Qiu¹, Xiaoyi Dai², Luhua Zhang³

Affiliations

¹ The School of Basic Medical Science and Public Center of Experimental Technology, Southwest Medical University, Luzhou, Sichuan Province, China.
² The School of Basic Medical Science and Public Center of Experimental Technology, Southwest Medical University, Luzhou, Sichuan Province, China. Electronic address: daixiaoyi@swmu.edu.cn.
³ The School of Basic Medical Science and Public Center of Experimental Technology, Southwest Medical University, Luzhou, Sichuan Province, China. Electronic address: zhluhua@swmu.edu.cn.

PMID: 35489677
DOI: 10.1016/j.jgar.2022.04.014

Abstract

Objectives: Citrobacter freundii is an important opportunistic pathogen, and carbapenem-resistant strains pose a significant challenge to public health. Here we report the genetic features of antimicrobial resistance genes of a carbapenem-resistant C. freundii SCLZS47 from hospital sewage by using whole genome sequencing.

Methods: Antimicrobial susceptibility was determined by the broth microdilution method. Whole genomic sequences of SCLZS47 were obtained by using the HiSeq 2000 combined with PacBio RSII platforms. Plasmid incompatibility types, resistance genes, and insertion elements were identified using the PlasmidFinder, ResFinder, and ISfinder, respectively.

Results: SCLZS47 has a circular chromosome and three resistance plasmids, and it carries 23 known ARGs. Among them, bla_CMY-135 and three copies of bla_CTX-M-14 are located on the chromosome. Sixteen ARGs are clustered in two accessory modules of a multidrug resistance (MDR) plasmid, and homologous recombination and transposition events contribute to the formation of these MDR regions. Carbapenemase genes bla_KPC-2 and bla_NDM-1 are carried by a pCKPC18-1-like plasmid and a pNDM-HN380-like plasmid, respectively. Conjugation experiments indicated that both KPC-2- and NDM-1-encoding plasmids are transmissible.

Conclusion: Analysis of the genetic features of resistance genes would help to better understand their transmission mechanisms and dynamics in bacterial community, which has significant clinical implications.

Keywords: Antimicrobial resistance genes; Citrobacter freundii; KPC-2; NDM-1.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Carbapenems* / pharmacology
Citrobacter freundii* / genetics
Genomics
Plasmids / genetics
beta-Lactamases

Substances

Carbapenems
beta-Lactamases
beta-lactamase NDM-1