中国首株格特隐球菌VGII基因型分离株XH91的分子和表型特征鉴定

Molecular and phenotypic characterization of a VGII genotype Cryptococcus gattii XH91 isolated in China

摘要:

摘要：【目的】研究我国首次临床分离的一株格特隐球菌VGII基因型菌株（XH91）的分子和表型特征。【方法】对受试株XH91进行血清型的分子鉴定；选取核基因组和线粒体基因组中共16个基因片段进行多位点序列分型；对受试株进行单倍体繁育、同性交配及异性交配能力评价；观察受试株的黑色素生成、荚膜厚度及37℃生长等表型特征。【结果】我国首株格特隐球菌VGII基因型菌株XH91为血清B型；该菌株在多位点序列分型上与温哥华岛致病基因型VGIIb一致；XH91能与a交配型发生交配，产生担孢子，而不能与α交配型发生交配且不具备单倍体繁育能力；XH91的黑色素生成、荚膜厚度及37℃生长等表型特征与参考株无明显差异。【结论】我国首株格特隐球菌VGII基因型菌株XH91在基因型、表型特征上均与温哥华岛VGIIb基因亚型一致，该结果将为我国格特隐球菌VGII基因型的分子流行病学和疾病监控提供重要资料。

关键词:关键词：格特隐球菌;基因型;序列分析;交配;表型

Abstract:

Abstract: [Objective] To characterize the molecular and phenotypic traits of the VGII genotype of Cryptococcus gattii isolate XH91 firstly isolated in China. [Methods] The serotype was identified by molecular method; multi-locus sequence typing (MLST) was performed based on 16 gene fragments both of nuclear and mitochondria genomes; the abilities of haploid fruiting, same-sex mating and opposite sex mating were all evaluated; the phenotypic traits including melanin production, capsule size, and growth at 37℃ were characterized. [Results] The isolate XH91 firstly isolated in China was serotype B. The isolate shared the same MLST genotype with the minor outbreak genotype VGIIb from Vancouver islands. Strain XH91 could mate with the reference strain of opposite mating type and produced basidiospores, but could not mate with the reference strain of same mating type and had no ability of haploid fruiting. We did not observe obvious difference between XH91 and reference strains for melanin production, capsule size, and growth at 37℃. [Conclusion] Based on the results from MLST and phenotypic analysis, the Cryptococcus gattii strain XH91 is identical with the minor outbreak genotype VGIIb from Vancouver islands. This study will be critical to gain further insight into the emergence and molecular epidemiology of the VGII genotype of Cryptococcus gattii from China.

Key words:Keywords: Cryptococcus gattii; genotype; sequence analysis; mating; phenotype