Patterns of bacterial translocation in experimental biliary obstruction

Biliary obstruction is associated with impaired intestinal barrier function and translocation of enteric bacteria to the systemic circulation. Traditional live culture techniques may overlook translocation of dead bacterial fragments that stimulate the inflammatory response. The aim of this study was to estimate the extent and pattern of bacterial translocation in experimental biliary obstruction.

Thirty 9-week-old male Wistar rats were randomized to undergo bile duct ligation (BDL, n = 20) or sham operation (n = 10). Seven days after operation, each animal received 1 ml of (111)indium-oxyquinolone-labeled Escherichia coli p.o. Samples of liver, spleen, mesenteric lymph nodes, and lung were harvested 4 h later and analyzed for live bacteria and (111)indium activity.

There was significantly more live bacterial translocation detected in BDL animals than in sham-operated animals (P = 0.00008, chi(2)). Labeled bacterial fragments were detected in all locations sampled in all animals. Sham-operated animals had significantly more labeled bacterial fragments detected in the liver (P = 0.0001) and the spleen (P = 0.03) than the BDL animals. The mean total bacterial survival in the BDL group was 30 +/- 13% and 0% in the sham operated group.

These results demonstrate that non-viable bacterial fragments are present in sterile extra-intestinal sites in normal animals and that translocation of live bacteria is markedly increased in experimental biliary obstruction. These results also suggest that failure of bacterial killing is an important factor facilitating bacterial translocation in the presence of established biliary obstruction.