Localization of translocating Escherichia coli, Proteus mirabilis, and Enterococcus faecalis within cecal and colonic tissues of monoassociated mice. Infect. Immun

Normal bacteria can translocate (migrate) across an intact intestinal mucosa, but the anatomical site of bacterial translocation has not been defined. Gastrointestinal (GI) cross-sections were obtained from mice monoassociated with high cecal concentrations of Escherichia coli, Proteus mirabilis, or Enterococcus faecalis. As previously reported (C. L. Wells, R. P. Jechorek, and K. J. Gillingham, Arch. Surg. 126:247-252, 1991), these mice had viable translocating bacteria recovered from mesenteric lymph nodes and livers. No abnormal GI histology was noted. Immunofluorescence was used to localize GI bacteria, and similar observations were made with each of the three bacterial species. Smaller numbers (P < 0.01) of bacteria were observed in stomach and small intestinal tissues than in cecal and colonic tissues, suggesting that the preferred site of tissue penetration for intestinal E. coli, P. mirabilis, and E. faecalis might be the cecum or colon as opposed to the stomach or small intestine. Bacterial translocation has been proposed to cause many complicating infections in hospitalized immunosuppressed patients, trauma patients, and postsurgical patients (for a review, see reference 16). As defined by Alexander et al. (1), bacterial translocation is the passage of viable and nonviabl