The occurrence of intestinal spirochaetosis in comparison with infections due to other enteropathogenic agents in a selected group of patients.

Objectives: Intestinal Spirochaetosis (IS) is a human large bowel infection due to Brachyspira aalborgi and B. pilosicoli associated with abdominal complaints (diarrhoea, pain, weight loss). The prevalence of IS in the general population in comparison with other gastrointestinal infections was poorly investigated till now. In our laboratory, we studied the occurrence of IS in a selected population with gastrointestinal complaints and/or potential risk factors for IS (immigration/travels from/through developing countries, HIV infection,male homosexuality) and compared the results with the occurrence of gastrointestinal infections due to viruses, bacteria other than spirochaetes and parasites. Methods: In the period 2002–2007, clinical samples belonging to 269 patients with gastrointestinal disorders were subjected to microbiological and virological investigations in our laboratory to search for enteropathogenic agents: from 258 patients we received faecal samples, from 9 patients both faecal samples and colonic biopsies, and from 2 only colonic biopsies. The research of intestinal spirochaetes was performed by a 16S rDNA Restriction Fragment Length Polymorphism-Polymerase Chain Reaction (RFLP-PCR) assay and PCR-positive samples were inoculated in a selective blood agar medium with spectinomycin and rifampin. Enteropathogenic agents other than spirochaetes were searched according to standard procedures by conventional (microscopy and culture) and molecular methods. Results: In 5 years 19 cases of IS (7%) were diagnosed by RFLP-PCR: 11 by B. aalborgi, 6 by B. pilosicoli and 2 mixed infections by both species. Ten of these patients were also infected by enteropathogenic agents other than spirochaetes. The other patients were infected by intestinal parasites only (17.1%), gastroenteric viruses only (3.7%) or bacteria other than spirochaetes only (5.9%) whilst in a relevant group of individuals (66.1%) no enteropathogenic agents were detected. Conclusions: Even if it refers to a selected population presenting gastrointestinal symptoms and risk factors for faecal-oral infections, the prevalence of IS reported in this study (7%) is of interest: in fact, our data suggest that IS may be more frequent than suspected in comparison with other gastrointestinal infections. Therefore, we are confident that physicians should take IS into account when subjects with chronic abdominal discomfort present to their attention.