白念珠菌临床分离株的基因分型及药物敏感性研究

Genotyping and Antifungal Susceptibility of Candida albicans Clinical Isolates

采用PCR方法对241株临床白念珠菌分离株编码rRNA的25SrDNA的 类内含子区进行分析,根据扩增条带大小进行基因分型及序列分析;药物敏感试验采用NCCLSM27-A微量稀释法方案;受试菌株为随机选择其中的80株白念珠菌临床分离株;试验药物为氟康唑、伊曲康唑、酮康唑、5-氟胞嘧啶以及两性霉素B。探讨白念珠菌基因分型与抗真菌药物敏感性之间的关系。基因分型表明:241株临床白念珠菌分离株中A型181株,B型34株,C型26株;B型含有 类内含子的保守区域,C型含有部分保守区域,A型则缺乏 类内含子的这些保守区域。白念珠菌A型为最常见的基因型。药物敏感试验提示:不同白念珠菌基因型对5-氟胞嘧啶敏感性存在显著差异,对其他4种抗真菌药物敏感性无显著差异。

To study the association between the genotypes of the C.albicans and antifungal susceptibility, total 241 clinical isolates were analyzed by PCR which was designed to amplify group I intron-containing region in 25S rDNA of C. albicans. Genotyping was done on the basis of amplified DNA band lengths. Sequencing and analysis of PCR products was performed. NCCLS M27-A microdilution method was applied. 80 clinical isolates of Candida albicans randomly selected among 241 isolates were tested and the tested drugs included fluconazole (FCZ), itraconazole (ICZ), ketoconazole (KCZ), 5-flucytosine (5-FC) and amphotericin B (AmB). Genotyping is showed that 241clinical isolates could be classified into three genotypes: genotype A (181 strains), genotype B (34 strains) and genotype C (26 strains). The sequence analysis of the amplified products showed that genotype B contained the conserved sequence elements of group Ⅰ intron and genotype C only harbored part of these conserved elements. However genotype A lacked all of these regions. Genotype A was the most isolated C.albicans strains. Antifungal susceptibility test indicated there were differences (among) susceptibilities to 5-flucytosine of the three genotypes of C. albicans. No statistically difference was found among other 4 antifungal drugs.