Aeromonas hydrophila-associated colitis in a male homosexual

A 37-year-old homosexual man was evaluated for a one-week history of hematochezia. Results of a physical examination were remarkable only for grossly bloody stool. Sigmoidoscopy to 30 cm showed a friable mucosa compatible with an acute colitis, and a rectal biopsy specimen demonstrated an increased plasma cell infiltrate. Stool cultures subsequently yielded Aeromonas hydrophila; serum human T-cell lymphotropic virus type III antibody titer was positive. The patient responded to a course of treatment with sulfamethoxazole and trimethoprim with resolution of his symptoms and restoration of the bowel to a normal sigmoidoscopic appearance. Aeromonas hydrophila infection should be considered in the differential diagnosis of acute proctocolitis, particularly in patients with underlying immunodeficiency states.