表皮葡萄球菌生物膜形成及相关基因的检测及评价

Detection and Evaluation for Biofilm Formation of Staphylococcus epidermidis and Related Genes

目的了解临床分离表皮葡萄球菌形成生物膜的状况,分析参与细菌黏附或聚集的icaA、aapf、be和atlE基因与生物膜形成的相关性。方法收集成都地区两所医院临床分离的表皮葡萄球菌45株,采用半定量黏附实验和扫描电镜检测其生物膜形成,PCR检测icaA、aapf、be和atlE基因,采用列联表2χ检验分析这些基因与生物膜形成的相关性。结果45株表皮葡萄球菌中生物膜形成株18株,占40.00%;PCR检测icaA、aapf、be和atlE基因阳性率分别为28.89%、77.78%、93.33%、80.00%;其中icaA、aap基因与生物膜形成相关性差异有统计学意义(P<0.05),icaA+/aap+及icaA-/aap+的表皮葡萄球菌均能形成生物膜,而icaA-/aap-表皮葡萄球菌不能形成生物膜;fbe、atlE基因与生物膜形成相关性差异无统计学意义。结论icaA、aap基因参与了表皮葡萄球菌生物膜的形成过程;且aap基因可能是生物膜形成的必需基因。

OBJECTIVE To investigate biofilm formation by clinical isolates of Staphylococcus epidermidis and analyze the relationship between biofilm formation and icaA, aap, fbe and atlE gene involved in initial adhesion/ accumulation of bacteria. METHODS The biofilm phenotype was performed by semi-quantitative adherence assay and scanning electron microscopy methods, and icaA, aap, fbe and atlE genes were detected by PCR in 45 strains of S. epidermidis isolated from two hospitals in Chengdu area, the significance of the relationship between these genes and biofilm phenotype were evaluated by contingency table Х^2 test. RESULTS 40. 00% isolates were with biofilm-positive phenotype;the positive rate of icaA, aap, fbe and altE genes detected by PCR was 28. 89%, 77.78%, 93.33%and 80.00%, icaA and aap genes were statistically related to biofilm formation in 45 clinical isolates（P〈0.05）. Both aap^＋/icaA^＋ and aap^＋/icaA^- isolates could form biofilms, while aap^-/ica^- isolates could not form biofilms. However, fbe and atlE genes with biofilm formation were statistically not correlated （P〈0.05）. CONCLUSIONS The icaA and aap genes are involved in the process for biofilm formation of S. epidermidis. Probably, aap is a necessary gene during the formation of biofilm.