Human Disseminated Protothecosis: The Skin is the “Window”?

Abstract

Human disseminated protothecosis is a rare infection caused by members of the genus Prototheca, an achlorophyllic algae always associated with debilitated hosts. The presence of non-budding cells and large, spherical cells (sporangia) with endosporulation (morula) in histology is proof of Prototheca infection. Regrettably, due to the lack of specificity of clinical features and low awareness among clinicians, protothecosis is always underestimated and misdiagnosed. The available data on a species-specific analysis of this infection are limited. In this review, we summarize the etiological, epidemiological, and clinical aspects of disseminated protothecosis. The potential pathogenicity and clinical differences between P. zopfii and P. wickerhamii were observed. Additionally, the skin not only became the main invasion site but also the most involved organ by the pathogen. With the increasing numbers of immunocompromised individuals throughout the world, the incidence of disseminated infection caused by Prototheca is bound to increase, and disseminated protothecosis that accompanies skin symptoms should be taken into account by clinicians.

Human protothecosis: A case report in northeastern Brazil

“…Todd et al reviewed 211 cases of protothecosis published between 1964 and 2017 and showed that 66 (31.2%) of these cases occurred in patients without any chronic condition or immunosuppression [ 2 ]. Our patient's case corroborates the information that even in immunocompetent individuals with some incidental disease, protothecosis should be considered in the differential diagnosis, especially when there is no clinical improvement through the antifungal drugs that are used for the most frequent mycoses [ 2 , 3 , 6 , 9 ].…”

“…Protothecosis is a rare condition, but large number of cases have been described in patients with underlying immunosuppression or several underlying diseases. Systemic steroid use, diabetes mellitus, hematological or solid-tissue malignancy and solid-organ transplantation are the main factors related to increased risk of this disease [ 2 , 3 , [5] , [6] , [7] , [8] , [9] , [10] , [11] , [12] ]. Todd et al reviewed 211 cases of protothecosis published between 1964 and 2017 and showed that 66 (31.2%) of these cases occurred in patients without any chronic condition or immunosuppression [ 2 ].…”

“…and nonsporulating tissue cells of Blastomyces spp., Cryptococcus spp., Paracoccidioides spp., muriform cells of chromoblastomycosis or vesicle or yeast-like cells of phaeohyphomycosis agents. Therefore, isolation of the agent in culture media is mandatory for a correct and reliable diagnosis [ 2 , 3 , [7] , [8] , [9] ]. Our case report showed that a second skin biopsy was necessary for diagnostic confirmation, after the lack of therapeutic response with itraconazole.…”

Simultaneous infection with Fusarium proliferatum and Prototheca wickerhamii localized at different body sites

“…We infer that infection of Prototheca wickerhamii may be due to sewage exposure. The diagnosis of Prototheca usually depends on morphological identification of the organisms in wet slide preparations of cultures and/or direct identification in tissue specimens [ 14 ]. Prototheca species reveal yeast-like colonies on Sabouraud dextrose agar but differ from fungi as they lack glucosamine in their cell walls [ 2 ].…”

“…Microscopic examination of the organism in culture reveals the same structures as those observed in tissue (spherical sporangia containing multiple endospores). Intracellular spores are characteristic for Prototheca species, yet the number and size are influenced by the culture medium and incubation time [ 12 , 14 ].…”