Strain typing of Candida alhiranstargeting to repeat sequences in each chromosome

白色念珠菌是健康人群和免疫低下人群中最常见的念珠菌病病原酵母菌。为了监测和预防念珠菌病，在菌株水平上区分白色念珠菌是很重要的。本研究对以25S rDNA和ALT重复序列为靶点的PCRS进行了评价。此外，微卫星重复序列的片段分析适用于白念珠菌在菌株水平上的进一步基因分型研究。179株临床分离株根据其25S rDNA序列分为A型(92株)、B型(37株)和C型(50株)，并通过ALT重复序列扩增将其分为5种类型(3、4、3/4、2/3/4和3/4/5型)。3C型分离株以白色念珠菌为主(A型占66.3%，B型占78.3%，C型占72.0%)。利用CDC3、HIS3、CAI和CAIII的微卫星片段分析可以区分这些菌株，这些片段在25SINT、P-II和AS-I的PCRS中显示出相同的电泳型。相反，使用25SINT、P-II和AS-I的PCRS可以区分在片段分析中显示相同分数的菌株。这些结果表明，三种不同系统的组合对于菌株水平的白念珠菌基因分型是有用的(DP=99.99)。此外，对巴西、日本和泰国分离的117株白色念珠菌进行的片段分析表明，每个国家都存在特定的基因类型

Candida albicans is the most etiologic yeast species of candidiasis in both healthy and immunocompromized individuals. For surveillance and prevention of candidiasis, it is important to discriminate C. albicans at the strain level. PCRs targenting 25S rDNA and ALT repeat element have evaluated in this study. Furthermore, fragment analysis of microsatellite repeats was adapted to further genotype study of C. albicans at the strain level. One hundred-seventy nine clinical isolates were grouped into genotypes A(92 isolates), B(37 isolates)and C(50 isolates)on the basis of their 25S rDNA, and each was further classified into 5 types(types 3, 4,3/4,2/3/4 and 3/4/5)by PCR amplification targeting ALT repeats. Type 3 C. albicans constituted the majority of isolates in any genotypes(66.3% for genotype A, 78.3% for genotype B and 72.0% for genotype C).The fragment analysis of microsatellites using CDC3, HIS3, CAI and CAIII allowed to discriminate the strains, which showed the same electophoretic patterns in the PCRs using 25SINT, P-II and AS-I. Conversely, the PCRs using 25SINT, P-II and AS-I discriminated the strain that showed identical scores in the fragment analysis. These results indicate that a combination of three different systems is useful for genotyping of C. albicans at the strain level(DP=99.99). Furthermore, the fragment analysis using 117 strains of C. albicans isolated in Brazil, Japan and Thailand suggested the presence of genotypes specific for each country