First case of human protothecosis in Canada: Laboratory aspects

Abstract

A case of bursitis due to Prototheca wickerhamii is briefly reported. In histological sections the organism stained well with fungal stains, grey with silver methanamine and red with periodic acid Schiff reagent. This unicellular achlorophyllous alga was studied on common laboratory media. The characterization of the Prototheca sp. depends largely on wet mount microscopic examination from broth or agar cultures which ensures the observation of endosporulation and a consistent absence of budding. Otherwise the growth rate and the pasty white colonies may lead to an erroneous identification, most likely as a Cryptococcus sp. P. wickerhamii lends itself very well to standard physiological tests used for the identification of yeasts. The strain was found insensitive to 5-fluorocytosine. The MIC of amphotericin B was 0.15 microgram/ml.

Human Protothecosis

“…are resistant to 5-flucytosine (64,136); P. zopfii and P. wickerhamii are sensitive to miconazole, while other species are not. For all species tested, griseofulvin shows in vitro resistance.…”

“…In general, Prototheca species show various susceptibility profiles, and there is no direct correlation between in vitro activity and clinical response, with the exception of a few cases (15,64,78,169). Thus, in vitro susceptibility testing is not indicated for routine patient management purposes for infections of the skin or bursae.…”

Cutaneous protothecosis: report of the second Brazilian case

“…Three species are known: P. wickerhamii, P. zopfii and P. stagnora, but only the first two have been known as agent of disease in humans and animals 26 . There are more than 80 cases of protothecosis described in the literature 7,10,13,14,19,20,21,23,26,35 ; only one of which occurred in Brazil 1 .…”

Protothecal bursitis after simultaneous kidney/liver transplantation: a case report and review

“…The spectrum of illness with Prototheca infection ranges from localized indolent skin and soft‐tissue infection (66% of cases) and olecranon bursitis in immunocompetent patients (15%) , to a devastating disseminated infection with algaemia and visceral infiltration (19% of cases) with high mortality in immunosuppressed hosts . At least 3 cases have been reported where the infection caused cholestatic hepatitis .…”

“…In most cases, the diagnosis was made by culture and histology showing the presence of granulomas. In 4 cases, bursectomy alone was curative, and in the other 3 cases, antifungals, such as itraconazole or topical AmB, were administered .…”