呼吸道白念珠菌分离株生物膜表型差异的机制

目的 探讨呼吸道白念珠菌分离株生物膜形成能力存在差异的可能分子机制.方法 呼吸道白念珠菌临床分离株及标准株ATCC90028体外粘附生长24 h形成生物膜,用XTT减低法测定其增殖情况,并分别提取生物膜态白念珠菌总RNA,用荧光定量RT-PCR的方法测定转录因子CPH1、EFG1和粘附分子ALS3、HWP1基因的表达,采用ACt的方法计算其相对表达量.结果 根据粘附生长的白念珠菌增殖情况,有8株临床株形成生物膜能力“高”,另7株临床株及标准株ATCC90028形成生物膜能力“低”.生物膜表型差异的菌株间转录因子CPH1、EFG1的表达无显著差异(P＞0.05),而粘附分子ALS3、HWP1基因的表达有显著差异(P＜0.05).结论 呼吸道白念珠菌分离株生物膜形成存在表型差异,其差异的机制可能与转录因子CPH1和EFG1以外的基因调控相关.

Mechanism of phenotype difference in biofilm formation by Candida albicans isolated from the respiratory tract

Objective To explore the molecular mechanism of the differences in biofilm formation abilities of Candida albicans isolated from the respiratory tract.Methods The biofilms formed by Candida albicans isolates from the respiratory tract and the standard strain ATCC90028 were examined for bacterial proliferation using XTT reduction assay.The mRNA expression of CPH1,EFG1,ALS3 and HWP1 in the isolates were measured with fluorescent quantitative RT-PCR.Results XTT reduction assay demonstrated a strong ability of biofilm formation in 8 clinical isolates,and a relatively low biofilm formation ability in 7 clinical isolates and ATCC90028 strain.The strong and weak biofilm formers showed significant differences in ALS3 and HWP1 mRNA expressions(P<0.05) but not in EFG1 or CPH1 mRNA expressions(P>0.05).Conclusion The clinical isolates from the respiratory tract have different biofilm formation abilities under regulation by genes other than the transcription factors CPH1 and EFG1.