Pathologic quiz case. Colon biopsy in a patient with diarrhea--Possible etiologic agent

Human intestinal spirochetosis, a sexually transmissible infection? Review of six cases from two sexually transmitted infection centres in Barcelona

Human intestinal spirochetosis (HIS) is a possible cause of chronic diarrhoea and affects mainly men who have sex with men (MSM) and people living with HIV. Diagnosis is based on colon biopsy, where spirochetes can be observed on the luminal surface, especially with the Warthin-Starry stain or similar silver stains. We conducted a retrospective descriptive study of all HIS cases diagnosed in two sexually transmitted infections (STI) centres in Barcelona from 2009 until 2018. The medical histories were reviewed to gather epidemiological, clinical, and diagnostic variables. Six patients were diagnosed with HIS. All the individuals were MSM, with a median age of 31.5 years (interquartile range [IQR] 29.5;49.25) and half of them were living with HIV. Five patients reported condomless anal intercourse and 4 patients had practised oro-anal sex previously. Concomitantly, two of them had rectal gonorrhoea, one had rectal Chlamydia trachomatis and none of them had syphilis. The predominant clinical symptom was diarrhoea (5 patients). All cases were diagnosed by a Warthin-Starry stain on a colon biopsy specimen, and mild inflammatory changes were found in 5 cases. Five patients were treated with metronidazole and one with benzathine penicillin G. Treatment was successful in all the patients. HIS should be considered in patients with chronic diarrhoea who report risky sexual practices and/or concomitant STI. HIS may also be sexually transmitted according to the context.

Colonic Spirochetosis in a 60-Year-Old Immunocompetent Patient: Case Report and Review

Spirochetes, a genetically and morphologically distinct group of bacteria, are thin, spiral-shaped, and highly motile. They are known causes of several human diseases such as syphilis, Lyme disease, relapsing fever, and leptospirosis. We report a case of colonic spirochetosis in a healthy patient presenting for surveillance colonoscopy. The diagnosis of intestinal spirochetosis was made accidentally during the histological examination of colonic polyps, which were removed during colonoscopy. We also performed an extensive review on intestinal spirochetosis with a focus on clinical presentation and outcomes of reported cases from the past two decades.

Intestinal spirochaetosis causing chronic diarrhoea in a patient with HIV infection

A 36-year-old Caucasian homosexual man was found to have HIV infection on routine screening. He had an eight-year history of chronic diarrhoea, which pre-dated the HIV diagnosis and did not improve after the introduction of combination antiretroviral therapy. After referral to the Gastroenterology department, he underwent fibreoptic colonoscopy. Colonic biopsies revealed the presence of intestinal spirochaetosis. He received a two-week course of metronidazole, which led to complete resolution of his diarrhoea. Intestinal spirochaetosis should be considered in the differential diagnosis of patients with HIV infection and chronic diarrhoea without other apparent cause.

Intestinal spirochetosis and colon diverticulosis

A case of intestinal spirochetosis in a 62-year-old white male is reported. The condition was characterized by chronic flatulence and episodes of intestinal hemorrhage, in addition to the evidence of hypotonic diverticular disease, with a large number of slender organisms in the colon epithelium and cryptae. Spirochetes were demonstrated by Whartin-Starry stain. The serologic tests for syphilis and HIV were positive. Spirochetosis was treated with penicillin G, and the patient remains free of intestinal complaints 20 months later.

Espiroquetosis colónica: una causa poco frecuente de diarrea en el adulto

Large intestine infection due to spirochetes was described in 1967 and is mainly related to two pathogens, Serpulina pilosicoli and Brachyspira aalborgi. Clinically, infection presents as diarrhea and/or rectorrhagia and is more frequent among homosexuals. Its prevalence is difficult to estimate but significant differences have been described according to the socioeconomic level of the area studied. We describe three cases of diarrhea due to spirochetes, which are of interest due to the lack of published cases in Spain. Based on these cases, we describe the main characteristics (morphological, therapeutic, etc.) of this infection.