80株中国大陆新生隐球菌环境株表型和分子特征的初步研究

Initial research of phenotypic and molecular characteristics of 80 Cryptococcus neoformans environmental strains from China mainland

目的了解中国大陆地区新生隐球菌环境株的分布情况,及其表型和基因型特征。方法采用CACA培养基培养1372份来自中国大部分地区私人和公共养鸽场所的鸽粪标本,分离出新生隐球菌,并对其表型和基因型特征进行分析。结果共分离出80株新生隐球菌,分离阳性率约为5.5%,所有菌株37℃生长良好,有完整荚膜,尿素酶试验阳性。ITS序列分析证实分离出的新生隐球菌均属于血清型A。M13-PCR显示,其基因型为我国及东南亚地区特征性的VNⅠc型,显示了与临床株的高度一致性。结论中国大陆地区的新生隐球菌临床株与环境株显示了高度的同源性,提示对于易感人群,阻断与相应环境的接触可有效预防新生隐球菌的感染。

Objective To investigate the phenotype, genotype and the distribution of environmental Cryptococcus neoformans from China mainland. Methods Cryptococcus neoformans strains were isolated by CACA medium from 1372 samples of pigeon droppings which had been gained in private and public square pigeon shelters from most regions of China mainland, then the phenotype and genotype of the isolated strains were analyzed by microsatelite-PCR. Results A total of 80 strains of Cryptococcus neoformans were isolated, the isolation rate was about 5.5%. All strains belonged to serotype A, grew well at 37℃, had complete capsule, and urease test were all positive. By ITS sequence analysis, they were identified to VN I c type, and had high consistency with the clinical strains from China and east Asia. Conclusion Clinical strains of Cryptococcus neoformans of China mainland may all come from the environment. For susceptible population, paying attention to environmental health would effectively prevent Cryptococcus neoformans infection.