Bacterial translocation in experimental shock is dependent on the strains in the intestinal flora

Background: Enteric microorganisms are responsible for a significant propor tion of post-surgical infections. Intestinal mucosal injury may permit tran slocation of bacteria and endotoxin. This study investigates translocation in peritonitis and ischemia/reperfusion by inoculating different bacterial species into the small intestine. Methods: Twenty-five pigs were monitored hemodynamically and divided into three groups: controls (C), ischemia/reper fusion (I/R), and peritonitis (P). Intramucosal pH (pH(i)) was calculated t onometrically. A perfusion tube was positioned in the ileum for inoculation of the bacterial strains. In a first study period a non-pathogenic bacteri um was used, whereas Escherichia coli strains with known ability to translo cate were used in a second. Blood and mesenteric lymph nodes (MLNs) were ob tained for bacterial culture and endotoxin analyses. Results: Mesenteric ar terial blood flow and pHi decreased in groups IIR and P. Endotoxin levels i ncreased in these groups in period 1, whereas in period 2 an increase over time was only observed in group P. No bacterial translocation to blood or M LNs occurred in period 1. In period 2 bacteria translocated to MLNs in all animals, including controls. Translocation to central and/or mesenteric ven ous blood was found in all groups, but mainly in I/R and P. The incidence o f mucosal injury was similar in the two periods. Conclusions: Since positiv e blood and MLN samples were only found in period 2, we conclude that trans location of bacteria seems to be more dependent on the presence of transloc ating strains in the intestinal bacterial flora than on the mucosal insult.