牛源近平滑念珠菌对氟康唑耐药性研究

Drug Resistance of Fluconazole in Clinical Isolates of Candida parapsilosis from Bovine Mycotic Mastitis

以牛源近平滑念珠菌(Candida parapsilosis)为试验菌株,采用微量稀释法进行药物敏感性试验,PCR扩增测序检测ERG11基因突变,Realtime PCR检测ERG11、CDR1、MDR1、MRR1基因的mRNA表达量,探讨耐药相关基因在牛源近平滑念珠菌耐唑类药物中的作用,为牛源近平滑念珠菌的耐药研究提供参考。结果表明,近平滑念珠菌对5-氟胞嘧啶、两性霉素B的敏感率均高于75%,对唑类药物的耐药率均高于50%,其中对氟康唑的耐药率最高,达58.3%;所有菌株的ERG11基因中均检测出错义突变A395T,耐氟康唑和剂量依赖菌株的ERG11基因中检测出同义突变T591C;氟康唑耐药组ERG11、CDR1、MDR1、MRR1基因表达水平均显著高于敏感组(P<0.05)。牛源近平滑念珠菌对唑类抗真菌药物的耐药率较高且具有多重耐药性。牛源近平滑念珠菌ERG11基因中的T591C突变以及ERG11、CDR1、MDR1、MRR1基因的高表达都可能在其对氟康唑耐药性的产生中起到一定的作用。

The role of resistance-related genes in azole-resistant isolates of Candida parapsilosis was explored,to provide theoretical bases for the drug resistance against bovine C.parapsilosis.C.parapsilosis from bovine mycotic mastitis as a test strain,and the drug susceptibility test was carried out by microdilution method.The mutation of ERG11 gene were detected by PCR amplification and sequencing,and Real-time PCR was used to analyze the mRNA expression of ERG11,CDR1,MDR1,and MRR1 genes.The results showed that the sensitivity rate of C.parapsilosis to 5-fluorocytosine and amphotericin B was over 75%,and the resistance rate to azoles was over 50%.Among them,the fluconazole resistance is the highest,reaching 58.3%;Missense mutation A395T was detected in ERG11 gene of all strains,synonymous mutation T591C was detected in ERG11 gene of fluconazole resistant and dose dependent strains;ERG11,CDR1,MDR1,MRR1 gene expression levels in fluconazole resistant group were significantly higher than those in sensitive group(P<0.05).These data demonstrates that bovine C.parapsilosis has highly resistant to azoles and multiple drug resistance.The T591C mutation in the ERG11 and hi-expression of ERG11,CDR1,MDR1,and MRR1 might have a certain role in drug resistance against fluconazole.