What is it about?
Human intestinal spirochetosis is the colonization of the large bowel by spiral-shaped bacteria of the genus Brachyspira. It is usually found by chance and causes no symptoms, and is more common in people with HIV, men who have sex with men and those exposed to infected animals, especially pigs. We describe a healthy 65-year-old man without these classic risk factors who developed sudden diarrhoea, abdominal pain, vomiting and rectal bleeding. Colonoscopy showed two ulcers in the colon, and biopsies with a special silver stain revealed a dense layer of spirochetes lining the bowel surface, the so-called false brush border. Usual stool tests were negative. He kept a Vietnamese pot-bellied pig as a pet. After 10 days of metronidazole his symptoms disappeared, and a colonoscopy 13 months later confirmed complete healing.
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Why is it important?
This case shows that intestinal spirochetosis can cause real disease and colonic ulcers even in people with a normal immune system, and that pets may be a source of infection. It reminds clinicians to request histology with appropriate stains for atypical colonic lesions and to ask about animal contacts.
Perspectives
This case is a nice example of One Health in everyday practice: the key to the diagnosis was a careful biopsy, and the key to the story was a pet pig. I am proud of the young colleagues in Trieste who followed this patient so carefully, including a follow-up colonoscopy more than a year later.
Professor Stefano Di Bella
Universita degli Studi di Trieste
Read the Original
This page is a summary of: Human intestinal spirochetosis presenting as colonic ulceration in an immunocompetent 65-year-old man, Infection, June 2025, Springer Science + Business Media,
DOI: 10.1007/s15010-025-02574-0.
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