Abstract:

Objective To understand the drug resistance and virulence distribution characteristics of different kinds of Enterococci isolated from the clinical specimens in Santai People's Hospital of Mianyang City. Methods Microdilution-based drug sensitivity test was used to determine the drug resistance of 485 isolates of Enterococcus faecium and 404 isolates of Enterococcus faecalis to 20 commonly used antibiotics. The 9 virulence genes（esp,acm,ace,hyl,asa1,gelE,cylA,efaA and cpd） of the isolates were detected by polymerase chain reaction（PCR）. Results Enterococcus faecium and Enterococcus faecalis had various levels of drug resistance to the 20 antimicrotics,and vancomycin-resistant Enterococcus and linezolid-resistant Enterococcus were determined. They have different rates and profiles of antimicrobial resistance. The vancomycin-resistant Enterococcus detection rates of the 2 groups were 9.7%（47/485） and 1.2%（5/404）,respectively（χ²=28.597,P<0.001）. Compared with vancomycin-sensitive Enterococcus faecium,the detection rates of virulence genes,esp,acm and hyl,in vancomycin-resistant Enterococcus faecium were higher（χ²=28.157,17.391 and 18.311,P<0.001）. Both VRE had high carrying rates of virulence genes and carried at least 2 virulence genes,but the carrying rates,types and patterns of virulence genes were not different significantly. Conclusions The clinical isolates of Enterococcus have high drug resistance rates to commonly used antibiotics,and have evolved to be highly virulent. The virulence of Enterococcus faecium has increased,and it is necessary for the hospital to attach importance and strengthen measures to prevent and control them.

Key words: Enterococcus faecium, Enterococcus faecalis, Drug resistance, Vancomycin-resistant Enterococcus, Virulence gene