Department of Laboratory Medicine, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, The First Affiliated Hospital of USTC, Hefei, China.
Department of Urology, Anhui Zhongke Gengjiu Hospital, Hefei, China.
Med Mycol. 2023 Oct 5;61(10). doi: 10.1093/mmy/myad097.
Candida tropicalis, a human conditionally pathogenic yeast, is distributed globally, especially in Asia-Pacific. The increasing morbidity and azole resistance of C. tropicalis have made clinical treatment difficult. The correlation between clonality and antifungal susceptibility of clinical C. tropicalis isolates has been reported. To study the putative correlation in C. tropicalis isolated from normally sterile body fluid specimens and explore the distinct clonal complex (CC) in Hefei, 256 clinical C. tropicalis isolates were collected from four teaching hospitals during 2016-2019, of which 30 were fluconazole-resistant (FR). Genetic profiles of 63 isolates, including 30 FR isolates and 33 fluconazole-susceptible (FS) isolates, were characterized using multilocus sequence typing (MLST). Phylogenetic analysis of the data was conducted using UPGMA (unweighted pair group method with arithmetic averages) and the minimum spanning tree algorithm. MLST clonal complexes (CCs) were analyzed using the goeBURST package. Among 35 differentiated diploid sequence types (DSTs), 16 DSTs and 1 genotype were identified as novel. A total of 35 DSTs were assigned to five major CCs based on goeBURST analysis. CC1 (containing DST376, 505, 507, 1221, 1222, 1223, 1226, and 1229) accounted for 86.7% (26/30) of the FR isolates. However, the genetic relationships among the FS isolates were relatively decentralized. The local FR CC1 belongs to a large fluconazole non-susceptible CC8 in global isolates, of which the putative founder genotype was DST225. The putative correlation between MLST types and antifungal susceptibility of clinical C. tropicalis isolates in Hefei showed that DSTs are closely related to FR clones.
热带假丝酵母菌是一种条件致病性人类酵母，分布于全球，尤其是亚太地区。由于热带假丝酵母菌的发病率不断增加和对唑类药物的耐药性，临床治疗变得困难。已有研究报道了临床分离的热带假丝酵母菌的克隆性与抗真菌药敏之间的相关性。为了研究从无菌体液标本中分离的热带假丝酵母菌的这种相关性，并探索合肥地区独特的克隆复合体（CC），我们收集了 2016 年至 2019 年来自四家教学医院的 256 株临床热带假丝酵母菌，其中 30 株为氟康唑耐药（FR）株。对 63 株分离株（包括 30 株 FR 株和 33 株氟康唑敏感株（FS））的遗传谱进行了分析，采用多位点序列分型（MLST）方法。使用 UPGMA（算术平均加权对组方法）和最小生成树算法对数据进行了系统发育分析。使用 goeBURST 包对 MLST 克隆复合体（CC）进行了分析。在 35 个分化的二倍体序列型（DST）中，发现 16 个 DST 和 1 个基因型为新的。基于 goeBURST 分析，将 35 个 DST 分为 5 个主要的 CC。CC1（包含 DST376、505、507、1221、1222、1223、1226 和 1229）占 FR 株的 86.7%（26/30）。然而，FS 株的遗传关系相对分散。当地的 FR CC1 属于全球分离株中一个较大的氟康唑不敏感 CC8，其中假定的起始基因型为 DST225。合肥地区临床热带假丝酵母菌分离株的 MLST 型与抗真菌药敏性之间的相关性表明，DST 与 FR 克隆密切相关。
