血液分离肠球菌毒力基因及生物膜形成相关性分析

A Correlation Analysis of Virulence Genes and Biofilm Formation in Enterococci Isolated from Blood

目的了解血液分离肠球菌毒力基因及其与生物膜形成能力的相关性。方法收集血培养分离粪肠球菌42株和屎肠球菌44株,采用纸片扩散法检测菌株对常规药物的敏感性;PCR法检测肠球菌6种毒力基因cyl、esp、asal、hyl、gelE和agg;采用结晶紫染色法测定肠球菌生物膜形成能力;统计分析肠球菌毒力基因与生物膜形成能力的关系。结果屎肠球菌对青霉素、氨苄西林、左旋氧氟沙星的耐药率高于粪肠球菌;除esp、hyl外,cyl、asal、gelE和agg基因在粪肠球菌检出率均显著高于屎肠球菌(P<0.05);血液分离肠球菌生物膜阳性率为32.6%(28/86),其中粪肠球菌和屎肠球菌生物膜阳性率分别为59.5%(25/42)和6.8%(3/44);肠球菌毒力基因的携带与其生物膜阳性率无相关性(P>0.05)。结论致血流感染的屎肠球菌其耐药率高于粪肠球菌,粪肠球菌生物膜的形成能力高于屎肠球菌,两者的毒力基因与生物膜形成不具相关性。

Objective To investigate the virulence genes of enterococci isolated from blood and its correlation with biofilm formation ability.Methods 42 strains of Enterococcus faecalis and 44 strains of Enterococcus faecium were collected from blood samples.Anti-microbial susceptibility test was carried out by K-B.PCR was used to detect the expressions of six virulence genes of enterococci including:cyl,esp,asal,hyl,gelE and agg.The ability of biofilm formation of Enterococcus was determined by crystal violet staining.The relationship between virulence genes of enterococci and biofilm formation ability was statistically analyzed.Results The E.faecium was more resistant to penicillin G,ampicillin and levofloxacin than E.faecalis.Except for esp and hyl,the detection rates of cyl,asal,gelE and agg genes in E.faecalis were significantly higher than in E.faecium ( P <0.05).The positive rates of biofilm formation in Enterococci,E.faecalis and E.faecium were 32.6%(28/86),59.5%(25/42) and 6.8%(3/44),respectively.The expressions of Enterococci virulence genes were not associated with their biofilm positive rates ( P >0.05).Conclusion The resistant rate of E.faecium is higher than E.faecalis isolated from blood,and the biofilm formation capacity of E.faecalis is higher than that of E.faecium.There is no correlation between the virulence genes expressions and biofilm formation.