Infection and Drug Resistance (Feb 2023)
Genomic Characterization of a Vancomycin-Resistant Strain of Enterococcus faecium Harboring a rep2 Plasmid
Abstract
Jie Shen,1,2,* Xiao Long,3,* Qi Jiang,1 Hao Xu,2 Qinming Wei,1 Qingmiao Shi,2 Yi Liu,2 Shanshan Xu,1 Xiaolu Ma,1 Lanjuan Li2 1Department of Medical Oncology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People’s Republic of China; 2State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People’s Republic of China; 3Department of Orthopedics, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People’s Republic of China*These authors contributed equally to this workCorrespondence: Lanjuan Li, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, No. 79 Qingchun Road, Hangzhou, 310003, People’s Republic of China, Tel +86-571-87236458, Fax +86-571-87236459, Email [email protected]: In China, vancomycin-resistant enterococci (VRE) was not a common occurrence, and research on the genetic context and transmission mechanism of vanA-plasmid was scarce. The aim of this study was to molecularly characterise a vancomycin-resistant Enterococcus faecium isolate from a bloodstream infection and determine the genetic environment and delivery pattern of the plasmid carrying vancomycin-resistant gene.Materials and Methods: In May 2022, a vancomycin-resistant strain of Enterococci was identified during routine screening for VRE bacteria at the First Affiliated Hospital, Zhejiang University School of Medicine. Utilizing matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), the isolate was accurately identified. Antimicrobial susceptibility and whole-genome sequencing (WGS) were employed to perform phenotypic and genomic analysis, respectively. Further bioinformatics analyses was carried out to characterize the vanA-bearing plasmid.Results: The antimicrobial susceptibility test showed that SJ2 strain was resistant to multiple antimicrobials, including ampicillin, benzylpenicillin, ciprofloxacin, erythromycin, levofloxacin, streptomycin, and vancomycin. Whole-genome analysis revealed that SJ2 strain carries several antimicrobial resistance genes and virulence determinants. MLST analysis found that SJ2 strain belongs to an unknown ST type. Plasmid analysis confirmed that the vanA gene was located on a variant of ~50 kb rep2 plasmid.Conclusion: Our study found that vanA-bearing rep2 plasmid is a potential source of dissemination and outbreak, and continuous surveillance is necessary to control its spread in Hangzhou, China.Keywords: vancomycin-resistant Enterococcus faecium, vanA, whole genome sequencing, rep2
