深部白色念珠菌感染临床株基因分型及药敏分析

Clinical isolates genotyping and susceptibility analysis of systemic Candida albicans infection

目的 了解天津地区院内深部白色念珠菌感染的好发部位 ,分析危险因素 ,研究其基因分型及不同基因型药敏分析。方法 收集深部白色念珠菌感染病例及临床分离株 ,应用 PCR方法扩增白色念珠菌2 5 S r DNA基因内含子区 ,内含子大小及其中可转座 型内含子片段的缺失或插入作为分型依据。采用微量肉汤稀释法对不同基因型白色念珠菌进行药敏分析。结果 深部白色念珠菌感染以肺部感染为主 ,老年患者居多 ,均有基础疾病 ,抗生素、激素的大量使用、各种侵入性操作及免疫功能低下是重要危险因素。临床分离的 2 5株白色念珠菌经 PCR分为三型 :A型 12株 (45 0 bp) ,B型 10株 (84 0 bp) ,C型 3株 (45 0 bp、84 0 bp)。A、B型为主要基因型 ,其药敏结果无显著性差异。结论 必须重视院内深部念珠菌感染的预防和监控。PCR方法快速简捷、特异性强、重复性好 ,比较适合临床白色念珠菌的分型研究。

Objective To investigate the incidence of nosocomial systemic Candida albicans infection in Tianjin area, its risky factors, the genotype and corresponding susceptibility analysis. Methods Systemic Candida albicans infectious cases and the clinical isolates were collected. Polymerase Chain Reaction (PCR) was used to amplify the intron area of the 25S rDNA of Candida albicans, the size of the intron and the absence and insertion of group I intron segment were adopted as the basis of typing. Broth microdilution method was introduced to the susceptibility analysis for different Candida albicans genotypes. Results The major systemic Candida albicans infection site was lung, and geriatric group was more vulnerable and all with other primary diseases. Extensive use of antibiotics and steroids, invasive manipulation and hypoimmunity were risky factors. Clinical isolated 25 strains of Candida albicans were divided into three types based on PCR tests: Type A (450bp), 12 strains; Type B (840bp), 10 strains; Type C(450bp and 840bp), 3 strains. Type A and B were the main genotypes. The difference of the results of susceptibility tests was not significant. Conclusion The prevention and surveillance of nosocomial systemic Candida albicans infection must be emphasized. PCR method is rapid and convenient, with high specificity and reproducibility, and suitable for the clinical typing study of Candida albicans.