Bacterial translocation from the gastrointestinal tracts of rats receiving thermal injury.

Rats receiving nonlethal thermal burns over 20 or 40% of their total body surface area were tested at various intervals for the translocation of indigenous bacteria from their gastrointestinal tracts to their mesenteric lymph nodes, peritoneal cavities, and bloodstreams. No indigenous bacteria were cultured from these organs of control rats or from rats receiving 20% burns. However, 44% of the rats receiving 40% burns exhibited viable Escherichia coli, Proteus mirabilis, Staphylococcus sp. and Clostridium sp. in their mesenteric lymph nodes 2 days after thermal injury. Bacterial translocation after burn stress also was tested in antibiotic-decontaminated rats monoassociated with E. coli. E. coli attained population levels in these animals of 10(8) to 10(9) per g cecum. E. coli translocated to 100% of the mesenteric lymph nodes of both the control and 40% burned rats. However, E. coli translocated at a greater incidence to the spleens, livers, and peritoneal cavities of the burned rats compared with translocation to these organs in control rats. The numbers of E. coli translocating to the mesenteric lymph nodes, spleens, and livers also were greater in the 40% burned rats than in control rats. By 14 days after thermal injury, the rats were able to clear E. coli from their spleens and livers, and the infection remained localized in the mesenteric lymph nodes. These results support the concept that the indigenous gastrointestinal flora or exogenous organisms colonizing the gastrointestinal tract are potential sources of septicemia after thermal injury.