Primary actinomycosis of the urinary bladder.

Actinomycosis is caused by bacilli of the Actinomyces sp. They are Gram-positive, anaerobic or microaerophilic non-spore-forming bacilli. Actinomyces israelii is the most common aetiological agent. A case is reported of primary actinomycosis in the urinary bladder successfully treated with ceftriaxone.