Distribution of vancomycin–resistant genes and virulence genes in vancomycin–resistant Enterococcus isolates from intensive care unit

Abstract

Objective To investigate the distribution of vancomycin–resistant genes and virulence genes in vancomycin–resistant Enterococcus (VRE) isolates from intensive care unit (ICU). Methods A total of 180 anal swabs were collected from patients in ICU in Tianjin Medical University General Hospital during September 2012 and May 2013. VRE strains were screened by ChromID agar method. Vitek 2 Compact system was used in drug sensitivity test, and the sensitivities to vancomycin and teicoplanin were further determined using Kirby–Bauer disk diffusion method. Vancomycin resistant genes vanA, vanB, vanC1 and virulence genes esp, hyl were detected by polymerase chain reaction(PCR). Results Nineteen strains of vancomycin resistant Enterococcus faecium were isolated from 180 anal swabs. All 19 VRE isolates were resistant to both vancomycin and teicoplanin, while they were susceptible to linezolid and tigecycline. All VRE isolates carried vanA and esp genes, and hyl gene was positive in 10 isolates. Conclusions VRE isolates from ICU are highly resistant to commonly used antibacterial agents, and most isolates carry vancomycin–resistant genes and virulence genes. Linezolid and tigecycline may be recommended for VRE infection in ICU. Key words: Enterococcus faecium; Vancomycin resistance; Virulence factors; Polymerase chain reaction; Drug resistance genes