Distribution characteristics and diversity of virulence genes in clinical isolates of vancomycin-resistant enterococci / 中国人兽共患病学报

ABSTRACT

The aim of this study is to determine the diversity of virulence genes carried by different vancomycin-resistant enterococci (VRE),which will provides a basis for studying pathogenic mechanism of VRE.Microdilution-based drug sensitivity test was applied to detect the vancomycin resistance of 490 Enterococcus faecium isolates and 862 Enterococcus faecalis isolates in Zhejiang area.The seven virulence genes (ace,asa1,cylA,efaA,esp,gelE and hyl) in the isolates of VRE were detected by PCR.According to the results of drug sensitivity test,10％ of the E.faecium isolates (49/490) and 0.8％ of the E.faecalis (7/862) were identified as VRE.In the vancomycin-resistant E.faecium isolates,five isolates were negative for any of the target genes and the other 44 isolates were positive for asa1,esp,gelE and hyl genes alone,in which the esp (73.5％,36/49) and hyl (53.1％,26/49) were the predominant genes and single or double virulence genes acted as the major carrying models.Except for the hyl gene,the vancomycin-resistant E.faecalis isolates were positive for the other six pathogenic genes,and the isolates could carry 3-6 pathogenic genes.All the data indicate that E.faeciurn is the major species of VRE in the local area,and the carrying rate,types and models of virulence genes in the vancomycin-resistant E.faecium and E.faecalis isolates are obviously different.