Instituto Nacional de Investigación Agropecuaria (INIA), Ruta No. 50, km 11, La Estanzuela, Colonia, 70006, Uruguay.
Private Practice, Montevideo, Uruguay.
Mycopathologia. 2018 Oct;183(5):853-858. doi: 10.1007/s11046-018-0274-5. Epub 2018 Jun 6.
Protothecosis is a rare disease caused by environmental algae of the genus Prototheca. These are saprophytic, non-photosynthetic, aerobic, colorless algae that belong to the Chlorellaceae family. Seven different species have been described. Prototheca zopfii genotype 2 and P. wickerhamii are most commonly involved in pathogenic infections in humans and animals. The objective of this work is to describe, for the first time, a case of protothecosis caused by P. zopfii genotype 1 in a dog. The dog, a 4-year-old mix bred male, was presented to a veterinary clinic in Montevideo, Uruguay, with multiple skin nodules, one of which was excised by surgical biopsy. The sample was examined histologically and processed by PCR, DNA sequencing, and restriction fragments length polymorphisms for the detection and genotyping of P. zopfii. In addition, transmission electron microscopy and scanning electron microscopy were performed. Histology showed severe ulcerative granulomatous dermatitis and panniculitis with myriads of pleomorphic algae. Algal cells were 4-17 µm in size, with an amphophilic, 2-4-µm-thick wall frequently surrounded by a clear halo, contained flocculant material and a deeply basophilic nucleus, and internal septae with daughter cells (endospores) consistent with endosporulation. Ultrastructurally, algal cells/endospores at different stages of development were found within parasitophorous vacuoles in macrophages. Prototheca zopfii genotype 1 was identified by molecular testing, confirming the etiologic diagnosis of protothecosis.
原壁菌病是一种由原壁菌属的环境藻类引起的罕见疾病。这些藻类是腐生的、非光合的、需氧的、无色的，属于绿藻科。已描述了七种不同的物种。原壁菌 2 型和 P. wickerhamii 最常导致人和动物的致病性感染。本工作的目的是首次描述一只狗患原壁菌病的病例，由 P. zopfii 1 型引起。这只狗是一只 4 岁的混种雄性，在乌拉圭蒙得维的亚的一家兽医诊所就诊，有多个皮肤结节，其中一个通过手术活检切除。对样本进行了组织学检查，并通过 PCR、DNA 测序和限制性片段长度多态性进行检测和鉴定，以检测和鉴定 P. zopfii。此外，还进行了透射电子显微镜和扫描电子显微镜检查。组织学显示严重的溃疡性肉芽肿性皮炎和脂膜炎，有成千上万的多形藻类。藻类细胞大小为 4-17µm，嗜碱性，2-4µm 厚的细胞壁常被一个清晰的晕圈环绕，含有絮凝物质和一个深嗜碱性核，以及与内生孢子形成一致的内部隔膜和子细胞（内生孢子）。超微结构显示，在巨噬细胞的寄生空泡中发现处于不同发育阶段的藻类细胞/内生孢子。通过分子检测鉴定了原壁菌 1 型，证实了原壁菌病的病因诊断。
