Abstract

Human disseminated protothecosis is a rare complication of infection and several prototheca (P.) species have been identified in localized cutaneous disorders. Only two rare cases of P. Zopfii species- mediated protothecosis have been reported in the United States. Cutaneous involvement has been reported to be the most common presentation. Herein, we present a rare case of disseminated protothecosis in a 68-year-old female who succumbed to P. Zopfii infection-related multi-organ failure while hospitalized in the Midwestern United States for a bone marrow transplant. On post-transplant course, her blood cultures findings showed staphylococcus epidermidis and another unknown gram-positive microorganisms. The unknown gram-positive microorganisms grew white, creamy yeast-like colonies on sabourauds and blood agar. A wet prep demonstrated large oval-shaped organisms with endospores on light microscopy. During this time, the patient continued to deteriorate and was found to have scattered ecchymoses and petechiae, including on a wound involving the left popliteal fossa and posterior calf, which was biopsied by dermatology team. Biopsy revealed unicellular pleomorphic round to cylindrical-shaped organisms with a large nucleus, a distinct nucleolus and a cell wall, which diffusely occupy the dermis and the subcutis. Rare asymmetric morula-like structures with primitive endospores were highlighted by Periodic Acid-Schiff and Grocott Methenamine Silver stains. DNA (Deoxyribonucleic acid) sequencing results additionally confirmed, that disseminated infection was indeed due to prototheca zopfii. Albeit, due to low frequency, variable clinical and microscopic features while identifying prototheca, high index of suspicion and ancillary studies, including molecular studies, could be helpful for identifying rare protothecosis (especially by P. Zopfii), while encountering cutaneous resistant infection in immunocompromised patients.

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