Gretchen Frieling, MD

Chad Jessup, MD, MS

Martin Mihm, MD

Erythematous plaques, vesiculobullous and ulcerative lesions with purulent discharge and crusting, are distributed on the calf. (Courtesy P. Hillesheim, DO.)

Protothecosis shows morula-like septations of P. wickerhamii sporangia image and unicellular endospores image of Prototheca. (Courtesy P. Hillesheim, DO.)



  • Exceedingly rare, indolent infection caused by achlorophyllic algae of genus Prototheca, primarily affecting immunocompromised individuals


Infectious Agents

  • Prototheca spp. is an achlorophyllic and ubiquitous algae

    • First described in 1964, it has been isolated from soil, water, animal, and food items

    • Found universally, except in Antarctica

  • Prototheca wickerhamii is species responsible for majority of infections in humans

Pathogenesis Unclear

  • Principle defense thought to be neutrophilic response, through engulfing and eradication of organisms

  • Patients with neutrophilic defects may be at increased risk of disease progression

Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Protothecosis

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