Role of early enteral feeding and acute starvation on postburn bacterial translocation and host defense

OBJECTIVES: To investigate the effect of: a) starvation during the preburn period and b) immediate postburn enteral nutrition on the permeability of the gut to microorganisms and the ability of the host to kill translocated bacteria. DESIGN: Prospective, randomized, experimental trials. SETTING: Laboratory. SUBJECTS: Balb/c mice and Hartley guinea pigs. INTERVENTIONS: In the first experiment, mice were starved for 0, 6, 12, 18, or 24 hrs before receiving gavage with 10(10) 14C-labeled Escherichia coli and a 20% burn injury. In the second experiment, guinea pigs received a 40% burn injury and were randomized to receive a complete enteral diet (175 kcal/kg/day) or infusion of an equal volume of lactated Ringer's solution via a previously placed gastrostomy for 6, 24, or 48 hrs. After each feeding period, 10(10) 14C Escherichia coli were infused intragastrically. In both experiments, the animals were killed 4 hrs after gavage, and mesenteric lymph nodes, spleen, liver, lungs, peritoneal fluid, and blood were harvested aseptically. MEASUREMENTS: For each tissue or fluid, the number of viable E. coli and radionuclide counts of the 14C E. coli were measured and the percentage of translocated bacteria that remained alive was calculated. MAIN RESULTS: In mice, 18 and 24 hrs of preburn starvation increased translocation only to the mesenteric lymph nodes, but it also enhanced bacterial killing in all tested tissues. Guinea pigs that were fed enterally for 6, 24, and 48 hrs postburn had significantly lower bacterial translocation in all tissues compared with animals infused with lactated Ringer's solution. Additionally, enhanced killing of translocating organisms was observed after 24 and 48 hrs of feeding. CONCLUSIONS: Starvation preburn has different consequences than starvation postburn on translocation and bacterial killing. Postburn enteral nutrition decreases the load of viable bacteria in the tissues via a double mechanism: an initial decreased translocation and a subsequent improved ability to kill bacteria that do translocate.