Protothecosis in the southeastern United States

A case of olecranon bursitis due to the achlorophyllic algae Prototheca species in an otherwise healthy 74-year-old man prompted our review of reported cases occurring in the southeastern United States. Most cases have involved the olecranon bursa, have occurred in otherwise healthy individuals, and were cured by simple excision. Intensive therapy with amphotericin B has been used successfully in a few cases that required systemic antibiotic therapy. The histologic features of this infection are predominantly those of granulomatous inflammation, with relatively easy demonstration of organisms using routine fungal stains.