S3952 Intestinal Spirochetosis in an Immunocompetent Patient

Introduction: Intestinal spirochetosis is a rare and poorly understood infection in which non-treponemal spirochetes attach to the surface epithelium of the colonic mucosa. Its prevalence ranges from 1.1% to 5% in developed countries. When symptomatic, intestinal spirochetosis can cause chronic watery diarrhea and generalized abdominal pain in immunocompromised patients. Here, we report an unusual case of symptomatic intestinal spirochetosis found during screening colonoscopy in an immunocompetent patient. Case Description/Methods: A 40-year-old healthy man with a history of 6 months of waxing and waning diarrhea presented for endoscopic evaluation. Review of systems was negative for weight loss, appetite changes, or blood per rectum. Physical exam and laboratory evaluation were unremarkable. Esophagogastroduodenoscopy and colonoscopy were performed with grossly normal findings and random colon biopsies were taken. Histopathology of the colonic mucosa showed a blue fringe on the surface of the epithelium on HandE staining. This finding has been termed a “false brush border” and is pathognomonic for intestinal spirochetosis. The immunohistochemical stain for Treponema pallidum identifies other intestinal spirochetes through cross-reactivity. With this stain, the microorganisms are highlighted at the apical surface of the epithelium of the colon. Due to the discovery of intestinal spirochetosis, HIV testing was performed which was negative. Of note, this patient was not immunosuppressed. Due to his ongoing symptoms, it was decided to treat the organism with metronidazole 500 mg 4 times a day for 10 days. At his 1-month follow-up, he reported an improvement in his diarrhea. The sexual orientation of this patient was homosexual. Discussion: We report a patient with symptomatic intestinal spirochetosis found on random colon biopsy and treated successfully with antibiotics. Our case reinforces the need for random colon biopsies in apparently normal looking colonic mucosa in symptomatic patients.