Increased type 1 fimbrial expression among commensal Escherichia coli isolates in the murine cecum following catabolic stress

Although indigenous bacteria intimately colonize the intestinal mucosa, und er normal conditions the intestinal epithelial cell is free of adherent bac teria. Nonetheless, commensal bacteria such as Escherichia coli adhere to a nd translocate across the intestinal epithelium in association with a numbe r of pathologic states including hemorrhagic shock, immunosuppression, trau matic tissue injury, and lack of enteral feedings. The adhesins involved in the adherence of indigenous E. coli to the intestinal epithelium in vivo f ollowing catabolic stress are unknown. We have developed a mouse model to s tudy the bacterial adhesins which mediate the increased intestinal adherenc e off. coli after partial hepatectomy and short-term starvation. Our studie s demonstrated that hepatectomy and starvation in the mouse were associated with a 7,500-fold increase in the numbers off. call bacteria adhering to t he cecum. In addition, erythrocyte agglutination studies, as well as immuno staining of fimbrial preparations and electron micrographs of the bacteria, revealed that surface type 1 fimbriae were more abundant in the commensal E. coli harvested from the ceca of the stressed mice. These E. coli isolate s adhered to a mouse colon cell line and injected cecal loops in a mannose- inhibitable manner, which suggests a role for type 1 fimbriae in the adhere nce of the E. coli isolates to the cecum in vivo following host catabolic s tress.