Granulomatous colitis associated with botryomycosis of Propionibacterium acnes

Propionibacterium acnes, an anaerobic, non-spore-forming, gram-positive bac illus, is a common inhabitant of the skin, and its virulence is considered to be low in humans. This report describes an unusual case of granulomatous colitis associated with P acnes infection in a 46-year-old woman. The affe cted cecum exhibited a tumor histologically characterized by massive transm ural infiltrates of small lymphocytes and noncaseating epithelioid granulom as with multinucleated giant cells. Botryomycotic granules were also found in the muscular layer and paracolic connective tissues and consisted of gra m-positive bacilli with filamentous growth. Polymerase chain reaction confi rmed the presence of P acnes 16S ribosomal DNA in the surgical specimen of the colon. The patient developed a postoperative P acnes-induced peritoniti s, which subsided with treatment with antibiotics and surgical drainage. Th e present case indicates that P acnes is one of the possible pathogens for granulomatous colitis.