Intestinal spirochetosis as a cause of chronic diarrhoea in patients with HIV infection: case report and review of the literature.

We describe a 77-year-old patient with HIV infection suffering from chronic diarrhoea whose colonoscopy findings showed normal appearance mucosa and tissue samples revealed the presence of a dense layer of spirochetes attached to the apical cell membrane. A literature search from 1996 to April 2009 identified 19 additional cases of intestinal spirochetosis in patients with HIV infection. Analysis of cases showed that intestinal spirochetosis causes chronic diarrhoea in men who have sex with men (92% of patients with reported HIV infection risk factors) who are not severely immunosuppressed (70% with CD4 lymphocyte cells >200/microL). Colonoscopy examination often revealed normal appearance mucosa. Haematoxylin and eosin stain of biopsy samples showed the presence of spirochetes, but Warthin-Starry silver staining makes organisms easier to detect. Patients promptly responded to metronidazole or penicillin therapy. In summary, invasive intestinal spirochetosis should be considered in the differential diagnosis of patients with HIV infection and chronic diarrhoea.