Comparative analyses of clinical and environmental populations of Cryptococcus neoformans in Botswana

Cryptococcus neoformans var. grubii (Cng) is the most common cause of fungal meningitis, and its prevalence is highest in sub-Saharan Africa. Patients become infected by inhaling airborne spores or desiccated yeast cells from the environment, where the fungus thrives in avian droppings, trees and soil. To investigate the prevalence and population structure of Cng in southern Africa, we analysed isolates from 77 environmental samples and 64 patients. We detected significant genetic diversity among isolates and strong evidence of geographic structure at the local level. High proportions of isolates with the rare MATa allele were observed in both clinical and environmental isolates; however, the mating-type alleles were unevenly distributed among different subpopulations. Nearly equal proportions of the MATa and MATα mating types were observed among all clinical isolates and in one environmental subpopulation from the eastern part of Botswana. As previously reported, there was evidence of ...新生隐球菌格鲁比变种（Cryptococcus neoformans var. grubii，简称Cng）是引发真菌性脑膜炎最常见的病原体，其流行率在撒哈拉以南非洲地区居于首位。人类可通过吸入环境中的气传孢子或干燥酵母细胞发生感染，该真菌可在鸟类粪便、树木及土壤中存活增殖。为探究南部非洲地区Cng的流行情况与种群结构，本研究对77份环境样本及64例患者来源的分离株进行了分析。研究团队在分离株中检测到显著的遗传多样性，同时在局部尺度上发现了强烈的地理结构证据。临床与环境分离株中均存在高比例携带罕见MATa等位基因的菌株；不过不同亚群间的交配型等位基因分布并不均衡。在全部临床分离株以及博茨瓦纳东部的一个环境亚群中，MATa与MATα交配型的占比几乎相等。正如既往研究所报道的，本研究同样发现了……