Protothecal olecranon bursitis: an unusual algal infection.

Prototheca is an achlorophyllic alga which rarely causes infections in humans and protothecal olecranon bursitis is remarkably rare. We report a case of a 76-year-old immunocompetent man presenting with pain and swelling of the right elbow secondary to protothecal infection. Initial cultures of the olecranon bursal aspirate revealed no growth; however, repeat aspiration after 2 months grew prototheca species on culture. Prototheca wickerhamii and Prototheca zopfii are the only 2 protothecal species known to cause human infections. Protothecal infection can manifest as skin infections, extremity infections, bursitis and very rarely as systemic infections. Treatment of protothecal infections remains controversial. Amphoterecin B, ketoconazole and fluconazole have been reported to yield a successful outcome. More recently, itraconazole has been found to be curative. Surgical excision of the bursa remains the definitive treatment. Our patient was treated with itraconazole with a favorable response.