Bulking fibre prevents translocation to mesenteric lymph nodes of an efficiently translocating Escherichia coli strain in rats

Background: starvation for 24 h prior to experimental haemorrhage increases bacterial translocation in rats. Forty-eight hours starvation alone causes pronounced microbiological changes in caecal contents and a marked increase in bacterial adherence to caecal epithelium. The aim of the present study was to examine whether bulking fibre prevents these microbiological changes induced by starvation, i.e. mucosal adherence and/or bacterial translocation with and without haemorrhage in rats. Methods: 32 rats were inoculated with the translocating Escherichia coli strain Kl-C1. Groups of these rats were then starved for 48 h with or without access to bulking fibre. An additional group of rats was given bulking fibre and subjected to haemorrhage. A control group was untreated and given regular food. Samples were taken from caecal contents, caecal epithelium, mesenteric lymph nodes and blood. A biochemical fingerprinting method was used to characterize and compare E. coli strains in all samples. Results: ingestion of bulking fibre alone for 48 h significantly reduced the frequency of Kl-C1 both incaecal contents and on caecal epithelium and completely prevented translocation of the strain, compared to starvation without bulking fibre for 48 h. Enforced stress (haemorrhage) increased bacterial translocation to the same level as starvation for 48 h. E. coli phenotypes found in mesenteric lymph nodes were also found adhering to the caecal epithelium. Conclusions: the presence of bulking fibre in gut lumen, by unknown mechanisms, reduces thefrequency of an inoculated translocating strain of E. coli in caecal contents and on caecal epithelium and prevents its translocation to mesenteric lymph nodes.