背景:侵袭性念珠菌病在全球范围内日益受到关注,尤其是在免疫功能低下的患者中,包括ICU患者。
目的:由于白色念珠菌是导致念珠菌血症的主要原因,研究念珠菌血症患者白色念珠菌的演变过程非常重要。
方法:我们分析了从不同身体部位分离的238株白色念珠菌。抗真菌药敏试验,对所有分离株进行了CAI基因座基因分型和多位点序列分型(MLST)。使用eBURST分析了仅在七个管家基因基因座之一上序列不同的总分离株之间的关系。
结果:通过结合七个管家等位基因对238个分离株进行的多位点序列分型分析揭示了175个二倍体序列类型,其中84个是新确定的。对这些数据的eBURST分析识别了19个克隆复合物(CC)和79个单例。此外,鉴定出73种CAI基因型。血液分离株显示最大基因型(49),显性基因型为CAI17-21和CAI21-21。口腔分离株具有25种CAI基因型,显性基因型为CAI17-21和CAI21-21。由于CAI等位基因数<30的分离株显示更容易传播,CAI17-21和CAI21-21是最常见的传播。最后,CAI基因型分为6组。
结论:这项工作揭示了从ICU念珠菌血症患者中分离出的口腔和血液菌株具有相同的显性CAI基因型。我们的数据扩展了白色念珠菌MLST数据库,并有助于了解侵袭性念珠菌病的演变和传播。
BACKGROUND: Invasive candidiasis is a growing concern worldwide, especially in immunocompromised patients, including ICU patients.
OBJECTIVE: As Candida albicans is the leading cause of candidaemia, it is important to investigate the evolution of C. albicans in patients with candidaemia.
METHODS: We analysed 238 strains of C. albicans isolated from different body sites. Antifungal susceptibility testing, CAI loci genotyping and multilocus sequence typing (MLST) of all isolates were performed. The relationships among the total isolates that differed in sequence at only one of the seven housekeeping gene loci were analysed using eBURST.
RESULTS: Multilocus sequence typing analysis in 238 isolates by combining seven housekeeping alleles revealed 175 diploid sequence types, in which 84 were newly identified. eBURST analysis for these data recognised 19 clonal complexes (CCs) and 79 singletons. Besides, seventy-three CAI genotypes were identified. Blood isolates showed maximum genotypes (49), and the dominant genotypes were CAI 17-21 and CAI 21-21. Oral isolates possessed 25 CAI genotypes, and the dominant genotypes were CAI 17-21 and CAI 21-21 as well. Since isolates with CAI allele numbers <30 showed easier transmission, CAI 17-21 and CAI 21-21 were the most frequently transmitted. Finally, the CAI genotypes were classified into six groups.
CONCLUSIONS: This work revealed the oral and blood strains isolated from the patients with candidaemia in ICU shared the identical dominant CAI genotypes. Our data expanded the C. albicans MLST database and helped with understanding the evolution and spread of invasive candidiasis.