Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA.
Infectious Disease Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA.
Med Mycol. 2022 Dec 29;61(1). doi: 10.1093/mmy/myac099.
Candida species are the most common causes of sight-threatening fungal ocular infections in temperate regions of the world. Despite their relevance, little is known about the emergence of novel species and the molecular epidemiology of these infections. Here, we molecularly characterized 38 yeast isolates collected from patients diagnosed with endophthalmitis or keratitis at Massachusetts Eye and Ear from 2014 to 2021. Sequencing of the ITS1-5.8S-/ITS2 regions demonstrated that this population of yeasts was dominated by Candida spp. (37 out of 38; 97%), with 58% of the cases caused by C. albicans (n = 22) and the remaining by emerging non-albicans species, predominantly by C. parapsilosis (n = 8) and C. dubliniensis (n = 6). One isolate each was identified as C. tropicalis and Clavispora lusitaniae. Interestingly, all C. dubliniensis were isolated from endophthalmitis and most C. parapsilosis from keratitis. Multilocus sequence typing analysis of C. albicans showed a prevalence of CC-1 isolates that has DST69 as the putative founder, with 64% of them belonging to this clonal complex (CC). Isolates grouped within this cluster were more predominant in endophthalmitis (10 out of 14; 71%). One C. albicans CC-1 isolate was multi-azole resistant. In conclusion, we observed that nearly half of the ocular infections caused by yeasts are associated with C. albicans, with evidence for the emergence of non-albicans species that are differentially enriched in distinct ocular niches. Candida albicans isolates clustered within the predominant CC-1 group were particularly more common in endophthalmitis, demonstrating a potential pattern of ocular disease enrichment within this clade.
念珠菌属是世界温带地区导致致盲性真菌性眼部感染的最常见原因。尽管它们很重要，但人们对新物种的出现以及这些感染的分子流行病学知之甚少。在这里，我们对从 2014 年至 2021 年在马萨诸塞眼耳医院（Massachusetts Eye and Ear）被诊断为眼内炎或角膜炎的患者中采集的 38 株酵母分离株进行了分子表征。ITS1-5.8S-/ITS2 区序列的测序表明，该酵母种群主要由念珠菌属组成（38 株中的 37 株；97%），58%的病例由白念珠菌（n=22）引起，其余由新兴的非白念珠菌物种引起，主要由近平滑念珠菌（n=8）和都柏林念珠菌（n=6）引起。每株各有一株鉴定为热带念珠菌和卢氏克鲁维酵母。有趣的是，所有的都柏林念珠菌均从眼内炎中分离出来，而大多数近平滑念珠菌均从角膜炎中分离出来。白念珠菌的多位点序列分型分析显示，以 DST69 为假定起源的 CC-1 分离株占优势，其中 64%属于该克隆复合体（CC）。属于该聚类的分离株在眼内炎中更为普遍（14 株中的 10 株；71%）。一株白念珠菌 CC-1 分离株对多种唑类药物耐药。总之，我们观察到，近一半由酵母菌引起的眼部感染与白念珠菌有关，并有证据表明非白念珠菌物种的出现，这些物种在不同的眼部生态位中差异富集。聚类在主要 CC-1 组内的白念珠菌分离株在眼内炎中更为常见，表明在该分支中存在眼部疾病富集的潜在模式。
