Microbial fingerprinting detects unique bacterial communities in the faecal microbiota of rats with...

An abnormal composition of the gut microbiota is believed to be associated with the pathogenesis of inflammatory bowel disease (IBD). We utilized terminal restriction fragment length polymorphism (T-RFLP) analysis to quantify faecal bacterial communities from rats with experimental colitis. Male Sprague Dawley rats (n=10/group) ingested 2% dextran sulfate sodium (DSS) or water for up to 7 days. Rats were killed and colonic tissues collected for histological analysis. Damage severity score in the distal colon was significantly greater (P<0.001) following DSS consumption compared to controls. T-RFLP faecal bacterial profiles generated with either MspI or CfoI revealed a significant difference (P<0.001) in community composition between healthy and colitic rats, with bacterial composition in healthy rats more variable than in rats with colitis. Operational taxonomic units (OTU: taxonomically related groups of bacteria) associated with either the healthy or colitic state were identified. OTU (116, 226, 360, and 948; CfoI) and (118 and 188; MspI) were strongly associated with untreated healthy rats, while OTU (94, 98, 174, and 384; CfoI) and (94 and 914; MspI) were predominantly associated with DSS-treated colitic rats. Phylogenetic OTU assignment suggested that Bacteroidales and Lactobacillus sp. were predominantly associated with the colitic and healthy rats, respectively. These results show that faecal bacterial profiling is a rapid, sensitive and non-invasive tool for detecting and identifying changes in gut microbiota associated with colitis. Restoring microbial homeostasis by targeting colitis-associated OTU through specific microbiological interventions could form the basis of novel therapeutic strategies for IBD.