Distribution and survival of Escherichia coli translocating from the intestine after thermal injury

The present investigation was performed to study the kinetics of tissue distribution and deposition of Escherichia colt and endotoxin translocating from the intestine after thermal injury. Escherichia coli was grown in the presence of ¹⁴C glucose and both labeled bacteria and endotoxin prepared from the labeled bacteria were used as translocation probes. Escherichia coli (10⁸ to 10¹⁰ bacteria) and E. coli endotoxin (100 μg per animal) were gavaged into the stomach immediately before a 30% burn injury was inflicted in mice. Animals were killed 1, 4, and 24 hours after burn injury. Translocation occurred extensively within 1 hour after burn injury. Expressed as amount of radioactivity per gram of tissue, translocation was greatest in the mesenteric lymph node (MLN) followed by spleen, lung, and liver. Translocation of endotoxin was similar to translocation of intact bacteria, with the exception that less radioactivity could be found in the peritoneal cavity and more in the liver. Both intact E. coli and endotoxin translocated directly through the intact bowel wall. Killing of bacteria was greatest in the MLN and spleen, approximating 95% to more than 99% of translocating bacteria. Killing efficiency was lowest in the lungs. It is concluded that estimation of translocation by viable bacterial counts in tissues grossly underestimates the extent of translocation of bacteria and ignores the extent of translocation of endotoxin. Translocation of en-dotoxin may have biologic significance that is independent of and in addition to translocation of intact bacteria.