阴道炎患者感染白念珠菌的耐药性及基因突变研究

Study of the drug resistance and genetic mutations of Candida albicans infecting patients with vaginitis

目的分离妇科阴道炎患者感染的白念珠菌,检测其耐药性及耐药株基因突变情况,以指导临床合理用药。方法取临床分离的白念珠菌耐药株和敏感株,经传代后再次进行药敏试验,以确定耐药情况。然后提取基因组DNA,进行电泳检测;采用PCR扩增ERG11基因并测序。结果药敏试验显示氟康唑对白念株菌GZ16传代后的MIC值为64μg/ml,判定GZ16为耐药株;SC5314的MIC值为2μg/ml,判定为敏感株;基因组DNA电泳,可见白念株菌GZ16、SC5314两菌株目的条带位于相同位置;对ERG11基因测序,在GZ16白念珠菌有G487T和T916C两个突变位点,SC5314白念珠菌有All67G、A1587G及T462A、T495A、A504G、A530C、C558T、C805T等8个基因位点的突变,并且还存在氨基酸的错义突变,包括:F105L(T462A)、D116E(T495A)、K128T(A530C)。结论分离自妇科阴道炎患者的白念珠菌部分对氟康唑耐药并发生ERG11基因G487T和T916C位点突变,该突变可能与白念珠菌对氟康唑耐药有关。

Objectives To isolate Candida albicans infecting patients with vaginitis and to determine its drug resistance and the state of genetic mutations in drug-resistant strains in order to guide the rational drug use in clinical settings.Methods Clinical isolates of C.albicans were determined to be drug-resistant strains or drug-sensitive strains,and a susceptibility test was again performed after passaging to verify drug resistance.Genomic DNA was extracted and detected using electrophoresis,and the ERG11 gene was amplified and sequenced using PCR. Results The susceptibility test indicated that the MIC of fluconazole for C.albicans GZ16 was 64μg/ml after passaging;GZ16was deemed to be a drugresistant strain.The MIC of fluconazole for C.albicans SC5314 was 2ug/ml,and SC5314 was deemed to be a drug-sensitive strain.Genomic DNA electrophoresis revealed that target bands for GZ16 and SC5314were in the same location.Sequencing of the ERG11 gene revealed that C.albicans GZ16 had 2point mutations,G487 Tand T916C,while C.albicans SC5314 had 8point mutations,All67 G,A1587G,T462 A,T495A,A504 G,A530C,C558 T,and C805 T.SC5314also had missense mutations of amino acids,including F105L（T462A）,D116E（T495A）,and K128T（A530C）. Conclusion Some of the C.albicans strains isolated from patients with vaginitis were resistant to fluconazole and they had point mutations in the ERG11gene（G487Tand T916C）.These mutations might be related to the resistance of C.albicans to fluconazole.