外排泵基因在白念珠菌生物膜耐药性产生中的作用

目的观察白念珠菌在生物膜形成不同时期对氟康唑的敏感性,及外排泵基因在生物膜耐药性产生过程中的作用。方法采用96孔微量培养皿进行白念珠菌生物膜的培养,用MTT法检测其对氟康唑的敏感性,并用半定量RT-PCR法测定生物膜形成不同时期CDR1、CDR2及MDR1基因表达的差异性。结果白念珠菌生物膜在较早期(2h)对氟康唑仍然敏感(2～4μg/mL),随着白念珠菌生物膜的不断成熟,其耐药性不断增高;CDR1及CDR2基因在生物膜形成的早中期及成熟期的表达明显上调,尤其早期的高表达更为明显,而MDR1基因的表达只在生物膜形成早期有明显的高表达。结论白念珠菌生物膜的耐药性随着其结构的成熟而不断增高;CDR1,CDR2及MDR1基因在生物膜形成早期有明显的高表达,但与生物膜耐药性的增加并不一致。因此,生物膜的耐药性可能是多种机制作用的结果。

The Role of the Efflux Pumps Genes in the Fluconazole Resistance of Candida Albicans Biofilms

Objection To explore the sensitivity to fluconazole of the candida albicans cells grown in developing biofilms and the role of the efflux pumps genes in the fluconazole resistance of C.albicans biofilm formation.Methods MTT method was used to test the sensitivity to fluconazole of biofilms preformed on the 96 wells microtiter plate and the expressions of CDR1、CDR2 and MDR1 were tested by RT-PCR.Results The MIC_(50) s of biofilms to fluconazole on early period (2h) were 2μg/mL～4μg/mL. The MIC_(50)s were increased with the biofilm maturation.Camparing with that of the planktonic cells,CDR1 and CDR2 were overex- pressed in different phases of the biofilms (10h,24h,48h),especially in the early phase,but MDR1 was overexpressed only in the early phase.Conclusion Drug resistance to fluconazole of the biofilm is incressed with the biofilm maturation.The overexpres- sions of CDR1、CDR2 and MDR1 do not coincide with the increasing of the drug resistance.