High protein diets are associated with increased bacterial translocation in septic guinea pigs

During sepsis, body protein stores are decreased due to an increase in protein catabolism. The utilization of nutritional support with high-protein diets has been used as a solution to the problem of sepsis-induced protein loss. Work from our laboratory, however, has shown that diets low in protein (5% of total calories) improve survival in septic animals as compared to high protein (20%) diets. The present study investigated the relationship between low protein diets and improved survival by determining whether septic animals receiving high-protein diets have increased bacterial translocation. Sepsis was induced in guinea pigs by the implantation of an osmotic minipump into the peritoneal cavity containing an equal mixture of Escherichia coli (10⁸) and Staphylococcus aureus (10⁸) or saline. On Day 3 postlaparotomy, the animals were randomized to one of four groups. The groups consisted of septic and nonseptic animals that received a diet with 5 or 20% of total calories as protein. Following 4 days of diet all animals received an instillation of ¹⁴C labeled E. coli (10¹⁰). Four hours later the animals were sacrificed and blood, mesenteric lymph nodes, spleen, lungs, and liver were removed for determination of radionuclide counts. Results indicated that the septic animals that received the high protein diet had more bacterial translocation, as indexed by higher radionuclide counts in the MLN, liver, lung and blood. These findings suggest that a low protein, enterally fed diet may improve survival in septic patients by decreasing the incidence of bacterial translocation.