Sulphate-reducing bacteria and hydrogen sulphide in the aetiology of ulcerative colitis

Abstract

BACKGROUND: The aetiology of ulcerative colitis is uncertain but may relate to environmental factors in genetically predisposed individuals. Sulphate-reducing bacteria (SRB) have been implicated through the harmful effects of hydrogen sulphide, a by-product of their respiration. Hydrogen sulphide is freely permeable to cell membranes and inhibits butyrate. This review examines the available evidence relating to SRB as a possible cause of ulcerative colitis. METHODS: A literature search was conducted using the PubMed database and search terms 'sulphate reducing bacteria', 'hydrogen sulphide', 'ulcerative colitis', 'mucous gel layer' and 'trans-sulphuration'. RESULTS: Search results were scrutinized and 113 pertinent full-text articles were selected for review. Collected data related to hydrogen sulphide metabolism, SRB respiration, mucous gel layer composition and their association with ulcerative colitis. CONCLUSION: There is evidence to implicate SRB as an environmental factor in ulcerative colitis. More sophisticated mucosal dissection and molecular techniques using bacteria-directed probes are required to determine an association definitively.