近平滑念珠菌复合群生物膜形成特点的研究

Study on the characteristics of biofilm formation of Candida parapsilosis complex

目的分析近平滑念珠菌、拟平滑念珠菌、似平滑念珠菌生物膜产量和代谢活性特点及氟康唑对其生物膜形成的影响。方法收集111株临床分离的近平滑念珠菌、拟平滑念珠菌和似平滑念珠菌,通过结晶紫、甲基四氮盐、扫描电子显微镜方法分析近平滑念珠菌复合群之间生物膜产生特点,并观察氟康唑对近平滑念珠菌复合群生物膜形成不同时间段的影响。结果在近平滑念珠菌复合群中,除了3株尿液分离的近平滑念珠菌外,其余108株(97.3%)均可产生生物膜,近平滑念珠菌的生物膜产量和代谢活性均最强,且生物膜代谢活性在不同培养时间段(6、12、24、48、72和96 h)逐渐升高,在72 h时达最高,96 h时反而降低。拟平滑念珠菌、似平滑念珠菌虽均可产生生物膜,但生物膜的代谢活性在各个培养时间段均较弱,且在各个时间段无明显差异。血液分离的近平滑念珠菌生物膜产量低于其他分离部位,生物膜代谢活性也最弱。氟康唑在不同培养时间段均可抑制生物膜的形成,48 h抑制作用最强。结论近平滑念珠菌复合群中近平滑念珠菌的生物膜产量和代谢活性均最强,血液分离的近平滑念珠菌生物膜产量和代谢活性低于其他分离部位,氟康唑对近平滑念珠菌复合群生物膜形成有明显的抑制作用。

Objective The yield of biofilm production and the metabolic activity of C.parapsilosis sensu stricto,C.orthopsilosis and C.metapsilosis were anlyzed to understand the effect of fluconazole on their biofilm formation.Methods 111 clinical isolates of C.parapsilosis sensu stricto,C.orthopsilosis and C.metapsilosis were collected,the differences in biofilm production characteristics among Candida parapsilosis complex were analyzed by crystal violet(CV)staining,tetrazolium salt(XTT)and scanning electron microscopy(SEM),the effect of fluconazole on C.parapsilosis complex biofilm formation in the different periods was observed.Results In the C.parapsilosis complex,except for 3 isolates of C.parapsilosis sensu stricto from urine,which could not produce biofilm,the remaining 108 isolates(97.3%)could produce biofilm.The biofilm metabolic activity increased gradually at different incubation times(6,12,24,48,72 and 96 h)and reached its highest at 72 h but decreased at 96 h.Although both C.orthopsilosis and C.metapsilosis could produce biofilm,the biofilm metabolic activity was weak during each culture period,with no significant difference.Blood-isolated C.parapsilosis sensu stricto had a lower yield for biofilm production than other isolated resources,the biofilm metabolic activity was also the weakest.In addition,fluconazole could inhibit biofilm formation at any time and the inhibition effect reached its strongest at 48 h.Conclusion C.parapsilosis sensu stricto was the strongest biofilm producer and had the highest metabolic activity among C.parapsilosis complex.Biofilm production and metabolic activities of C.parapsilosis sensu stricto isolated from blood were lower than those of other isolated resources.Fluconazole had a significant inhibitory effect on the biofilm formation of the C.parapsilosis complex.