Hopf Cynthia, Graham Erin A, Gibas Connie F C, Sanders Carmita, Mele James, Fan Hongxin, Garner Michael M, Wiederhold Nathan P, Ossiboff Robert, Abou-Madi Noha
Department of Clinical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY, United States.
Department of Comparative Diagnostic and Population Medicine, University of Florida College of Veterinary Medicine, Gainesville, FL, United States.
Front Vet Sci. 2020 Jan 31;7:25. doi: 10.3389/fvets.2020.00025. eCollection 2020.
The genus is composed of ubiquitous, pigmented, saprotrophic fungi and includes both terrestrial and waterborne species. Though species are generally considered opportunistic pathogens, exophialosis can be an important cause of morbidity and mortality in aquatic and semi-aquatic species. Over a 6-year period, a captive 32-year-old male eastern hellbender (), was treated for recurring, slow growing, ventral midline cutaneous masses. Excisional biopsies were characterized histologically by granulomatous dermatitis with low numbers of intralesional, pigmented fungal conidia and hyphae. Bacterial and fungal cultures of the masses and skin were negative on two separate submissions. Polymerase chain reaction amplification of a short fragment of the fungal 28S large subunit (LSU) ribosomal RNA was positive with 100% nucleotide sequence identity to several species of . Following recurrence after successive rounds of antifungal therapy, euthanasia was elected. At necropsy, similar dermal granulomatous inflammation and intralesional pigmented fungal elements as observed in excisional biopsies formed a thick band in the dermis and extended through the coelomic body wall. Visceral dissemination was noted in the lung and kidney. Postmortem DNA sequence analysis of a large portion of the fungal LSU as well as the internal transcribed spacer (ITS) from a portion of frozen affected dermis identified the fungus as a novel species, sp. 1 (UTHSCSA R-5437).
该属由无处不在的、有色素的腐生真菌组成,包括陆生和水生种类。尽管该属物种通常被认为是机会性病原体,但外瓶霉病可能是水生和半水生物种发病和死亡的重要原因。在6年的时间里,一只圈养的32岁雄性东部隐鳃鲵(Cryptobranchus alleganiensis alleganiensis)因反复出现、生长缓慢的腹中线皮肤肿块而接受治疗。切除活检的组织学特征为肉芽肿性皮炎,病灶内色素沉着的真菌分生孢子和菌丝数量较少。肿块和皮肤的细菌和真菌培养在两次单独送检时均为阴性。真菌28S大亚基(LSU)核糖体RNA短片段的聚合酶链反应扩增呈阳性,与几种外瓶霉属物种的核苷酸序列同一性为100%。在连续几轮抗真菌治疗后复发,最终选择实施安乐死。尸检时,在切除活检中观察到的类似真皮肉芽肿性炎症和病灶内色素沉着的真菌成分在真皮中形成一条厚带,并延伸穿过体腔壁。在肺和肾中发现了内脏播散。对冷冻的受影响真皮部分的大部分真菌LSU以及内部转录间隔区(ITS)进行死后DNA序列分析,确定该真菌为一个新物种,外瓶霉属sp. 1(UTHSCSA R-5437)。