Singh Karuna, Rani Jyoti, Rai Govind Kumar, Singh Major
Department of Zoology, Mahila Mahavidyalaya, Banaras Hindu University, Varanasi-221005.
Division of Crop Improvement, Indian Institute of Vegetable Research, Jakhini-Shahanshahpur, Varanasi-221305.
Med Mycol. 2017 Nov 1;55(8):820-827. doi: 10.1093/mmy/myx001.
We describe Mus musculus castaneus as a new mammalian host for Cryptococcus neoformans var. grubii (VNI). Eighteen apparently healthy adults and pups of the rodent were collected from human dwellings in Varanasi, a city of India. Both clinical and behavioral examinations of the rodents did not reveal any sign of the disease. Among visceral organs, histological examination of only liver exhibited the presence of single celled, encapsulated, Southgate's mucicarmine positive fungal structures consistent with C. neoformans. Nevertheless, culture of tissue homogenates of brain, lungs, liver, and kidneys yielded white colonies on Sabouraud's dextrose agar and brown mucoid colonies of C. neoformans on Staib's and Tobacco agar media. The pathogen was isolated from habitat soil as well as fresh faeces of the animals. All isolates were urease positive, nitrate and canavanine-glycine bromothymol blue negative, exhibited phenoloxidase activity and grew at 37°C. The isolates were identified as C. neoformans var. grubii with ITS primers and unique marker (GACA)4. The pathogen when inoculated in immunosuppressed mice showed low pathogenicity. To our knowledge, we for the first time report case cluster of Mus musculus castaneus as new passenger host for C. neoformans var. grubii (VNI).
我们将小家鼠栗色亚种描述为新型隐球菌格鲁比变种（VNI）的一种新的哺乳动物宿主。从印度瓦拉纳西市的人类住所收集了18只看似健康的该啮齿动物成年个体和幼崽。对这些啮齿动物进行的临床和行为检查均未发现任何疾病迹象。在内脏器官中，仅肝脏的组织学检查显示存在与新型隐球菌一致的单细胞、有荚膜、南门氏黏液卡红阳性真菌结构。然而，脑、肺、肝和肾组织匀浆在沙氏葡萄糖琼脂上培养产生白色菌落，在施泰布琼脂和烟草琼脂培养基上培养产生新型隐球菌的棕色黏液样菌落。该病原体从动物栖息地土壤以及新鲜粪便中分离得到。所有分离株脲酶阳性，硝酸盐和刀豆氨酸-甘氨酸溴百里酚蓝阴性，具有酚氧化酶活性，且能在37°C生长。这些分离株用ITS引物和独特标记（GACA）4鉴定为新型隐球菌格鲁比变种。当将该病原体接种到免疫抑制小鼠体内时，显示出低致病性。据我们所知，我们首次报告了小家鼠栗色亚种作为新型隐球菌格鲁比变种（VNI）新的偶然宿主的病例聚集情况。
