Department of Clinical Pathology, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, 681 Samsen Road, Vajira District, Dusit, Bangkok, 10300, Thailand.
Microbiology Laboratory, Department of Central Laboratory and Blood Bank, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, Bangkok, Thailand.
Mycopathologia. 2020 Jun;185(3):503-514. doi: 10.1007/s11046-020-00456-7. Epub 2020 May 21.
The basidiomycete yeast Cryptococcus neoformans causes disease in immunocompromized patients. Whole genome sequencing (WGS) technology provides insights into the molecular epidemiology of C. neoformans. However, the number of such studies is limited. Here we used WGS and multilocus sequence typing (MLST) to determine the genetic diversity of C. neoformans isolates and genetic structures of their populations among patients admitted to a single hospital in Bangkok, Thailand. Seven isolates from six patients collected during 1 year were identified as C. neoformans sensu stricto according to colony morphology, microscopy, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and nucleotide sequence analysis of internal transcribed sequences. These isolates were sensitive to the antifungal drugs amphotericin B, fluconazole, 5-flucytosine, voriconazole, itraconazole and posaconazole and were mating type α and molecular type VNI. MLST analysis identified ST4, ST5 and ST6. We further employed WGS to determine the genetic diversity and relationships of C. neoformans isolated here combined with C. neoformans sequences data acquired from a public database (n = 42). We used the data to construct a phylogenetic tree. WGS provided additional genomics data and achieved high discriminatory power for identifying C. neoformans isolates isolated in Thailand. This report further demonstrates the applicability of WGS analysis for conducting molecular epidemiology and provides insight into the genetic diversity of C. neoformans isolates from one hospital in Thailand.
新型隐球菌是一种担子菌酵母，会导致免疫功能低下的患者发病。全基因组测序（WGS）技术为了解新型隐球菌的分子流行病学提供了线索。然而，此类研究的数量有限。在这里，我们使用 WGS 和多位点序列分型（MLST）来确定泰国曼谷一家医院住院患者中新型隐球菌分离株的遗传多样性及其种群的遗传结构。根据菌落形态、显微镜检查、基质辅助激光解吸/电离飞行时间质谱和内部转录序列核苷酸序列分析，从 6 名患者中采集的 7 株分离物被鉴定为严格意义上的新型隐球菌。这些分离物对两性霉素 B、氟康唑、5-氟胞嘧啶、伏立康唑、伊曲康唑和泊沙康唑等抗真菌药物敏感，且为交配型α和分子型 VNI。MLST 分析鉴定出 ST4、ST5 和 ST6。我们进一步使用 WGS 来确定这里分离的新型隐球菌的遗传多样性和关系，并结合从公共数据库（n=42）获得的新型隐球菌序列数据。我们使用这些数据构建了一个系统发育树。WGS 提供了额外的基因组学数据，并实现了对泰国分离的新型隐球菌分离株进行高分辨力识别的能力。本报告进一步证明了 WGS 分析在进行分子流行病学研究中的适用性，并为了解泰国一家医院的新型隐球菌分离株的遗传多样性提供了深入的见解。
