Genomic investigation of the vancomycin-resistant Enterococcus faecium in a tertiary hospital in China

OBJECTIVES: In light of a VREfm spread in a large tertiary hospital in China, this study aimed to explore the transmission dynamics and genetic characteristics of these isolates within a global context. METHODS: A total of 27 VREfm were collected from a hospital in Guangdong province, China. Antimicrobial susceptibility testing, whole-genome sequencing, and transmission dynamics analysis were performed. Additionally, global sequence type 80 (ST80) data were gathered for genetic comparison, and complete plasmid sequences were reconstructed to characterize the genetic environment surrounding the vanA genes. RESULTS: The study identified VREfm ST80 as the main agent of the patient infection, with the exception of four ST789 isolates identified on environmental surfaces within one bed. The genomes displayed high clustering, with similar profiles of virulence factors and antimicrobial resistance genes. The study observed that genetically similar VREfm strains were distributed across different beds. Moreover, VREfm ST80 from the hospital clustered with other Chinese isolates and exhibited a higher number of VFs compared to other lineages. Although vanA genes were present in different STs, the vanA-carrying plasmids shared highly similar backbone structure, with Tn1546-associated elements detected in each. CONCLUSION: This study sheds light on the genetic epidemiology of a VREfm spread in a Chinese hospital through comparison with global isolates. To control the spread of VREfm within hospitals, the implementation of active screening programs and rigorous infection control measures is essential.