The first report of the vanC (1) gene in Enterococcus faecium isolated from a human clinical specimen

The vanC(1) gene, which is chromosomally located, confers resistance to vancomycin and serves as a species marker for Enterococcus gallinarum. Enterococcus faecium TJ4031 was isolated from a blood culture and harbours the vanC(1) gene. Polymerase chain reaction (PCR) assays were performed to detect vanXYc and vanTc genes. Only the vanXYc gene was found in the E. faecium TJ4031 isolate. The minimum inhibitory concentrations of vancomycin and teicoplanin were 2 µg/mL and 1 µg/mL, respectively. Real-time reverse transcription-PCR results revealed that the vanC(1) and vanXYc genes were not expressed. Pulsed-field gel electrophoresis and southern hybridisation results showed that the vanC(1 ) gene was encoded in the chromosome. E. faecalis isolated from animals has been reported to harbour vanC(1) gene. However, this study is the first to report the presence of the vanC(1) gene in E. faecium of human origin. Additionally, our research showed the vanC(1) gene cannot serve as a species-specific gene of E. gallinarum and that it is able to be transferred between bacteria. Although the resistance marker is not expressed in the strain, our results showed that E. faecium could acquire the vanC(1) gene from different species.