Background: Peritoneal colonization is a crucial event in the pathogenesis of peritonitis and its local complications. Adherence to the serosal mesothelium is mediated in a number of microorganisms derived from the digestive tract (especially E. coli) by type-1 fimbriae which have an oligosaccharide specificity.
Purpose: To evaluate the effect of repeated peritoneal washes with saline solution and oligosaccharides on E. coli peritoneal adherence in a rat peritonitis model.
Methods: Sixty rats were randomized in 3 groups of 20. E. coli was inoculated at a constant concentration of 10(8)/mL per 100 g of weight. Then, peritoneal washes were achieved daily during three consecutive days (D1, D2, D3), with saline solution in Group I (control group), Methyl alpha-D-Mannoside (MADM) in Group II, and p-Nitro-phenyl alpha-D-Mannoside (pNADM) in Group III. Peritoneal samples were obtained before and after lavage at D1, D2, and D3. Microbial recovery was expressed as cfu/mg of tissue, and converted into a percentage of the initial value. A 10% threshold defined efficiency of the wash (inhibition of adherence for 90% of bacteries).
Results: Compared with data from Group I, E. coli peritoneal adherence was significantly lower after washes in Group III (D1: p = 0.03; D2: p = 0.009; D3: p = 0.003). Repeated washes were more efficient in Group III than in Group II (D1: p = 0.1; D2: p = 0.5; D3: p = 0.001).
Conclusion: These results suggest that the addition of oligosaccharides, especially of pNADM, reduces the peritoneal adherence of E. coli when a peritoneal wash is performed for peritonitis.