Actinomyces as a cause of recurrent perianal fistula in the immunocompromised patient.

Actinomycosis is an uncommon bacterial infection that has a characteristic chronic indolent course. Patients with this infection frequently undergo multiple surgical procedures before a correct diagnosis is made. Perianal actinomycosis should be suspected if a nontender perianal mass is found to contain thin purulent material and small yellow particles (sulfur granules). The diagnosis is confirmed by special stains and anaerobic cultures. Recognition of this infection is important because successful treatment requires combined surgical and antibiotic therapy. We report two patients, one with diabetes mellitus and one with human immunodeficiency virus III, who had recurrent perianal abscesses caused by Actinomyces and were treated successfully with surgical drainage and antimicrobial therapy.