肠球菌属生物膜表型和基因型相关性分析

目的了解肠球菌属生物膜形成能力及其毒力基因携带率,分析生物膜的形成能力与毒力基因间的相关性。方法收集复旦大学附属华山医院2015-2017年临床分离自无菌体液的肠球菌属细菌,使用结晶紫染色法测定肠球菌的生物膜形成能力并进行形成能力的强弱分级,采用PCR方法筛查7种常见的肠球菌毒力基因以及Fsr群体感应系统基因(fsrA、fsrB、fsrC)。结果共收集了112株肠球菌菌株,其中粪肠球菌52株,屎肠球菌60株;两者生物膜形成的阳性率分别为63.46%和13.33%,差异具有统计学意义(P<0.001)。52株粪肠球菌毒力基因携带率分别为:esp 40.38%、gelE 69.23%、sprE 73.08%、asa157.69%、cylA 46.15%、cylB 48.08%、cylM 50.00%、fsrA 40.38%、fsrB 42.31%、fsrC 80.77%,携带esp、asa1、cylA、cylB、cylM和fsrB基因的菌株更易形成生物膜。60株屎肠球菌毒力基因携带率分别为:esp 65.00%、gelE 10.00%。结论粪肠球菌比屎肠球菌更容易形成生物膜;多种毒力基因与生物膜形成相关,提示生物膜的形成并不是由单一基因调控,而是由多个基因多系统调控。

Correlation between phenotype and genotype of Enterococcus biofilm formation

Objective This study was designed to understand the ability of Enterococcus biofilm formation and the prevalence of relevant virulence genes,and to analyze the correlation between biofilm formation ability and virulence genes.Methods Enterococcus isolates were collected from Huashan Hospital,Fudan University during the period from 2015 to 2017.Biofilm formation was determined by crystal violet staining and the virulence genes were identified using PCR assay.Results A total of 112 strains of Enterococcus were collected,including 52 strains of E.faecalis and 60 strains of E.faecium.Biofilm formation was confirmed in 63.46%of E.faecalis strains and 13.33%of E.faecium strains.The prevalence of esp,gelE,sprE,asa1,cylA,cylB,cylM,fsrA,fsrB,and fsrC genes was 40.38%,69.23%,73.08%,57.69%,46.15%,48.08%,50.00%,40.38%,42.31%,80.77%in E.faecalis.The strains carrying esp,asa1,cylA,cylB,cylM,and fsrB were more readily to form biofilm.The prevalence of esp and gelE genes was 65.00%and 10.00%in E.faecium respectively.Conclusions E.faecalis strains show higher biofilm formation ability than E.faecium.A variety of virulence genes are significantly associated with biofilm formation,suggesting that biofilm formation is regulated by multiple genes and multiple systems instead of a single gene.