Effects of protein malnutrition and endotoxin on the intestinal mucosal barrier to the translocation of indigenous flora in mice.

Since protein malnourished or endotoxemic patients are at increased risk of developing nosocomial infections with enteric organisms, we investigated the effects of these risk factors alone and in combination on the intestinal mucosal barrier to bacteria. Protein malnutrition resulted in severe ileal atrophy that was directly related to the length of time the mice were protein malnourished. Although protein malnutrition did not promote bacterial translocation from the gut to systemic organs, the protein-malnourished mice were more susceptible to endotoxin-induced bacterial translocation than normally nourished mice (p less than 0.01). Since the gross epithelial damage documented after endotoxin administration in normally nourished mice was diminished after protein malnutrition, there was no correlation between the gross appearance of the epithelial mucosal barrier and the extent of endotoxin-induced bacterial translocation. These results suggest that the synergistic effect of endotoxin plus protein malnutrition on bacterial translocation is not primarily related to failure of the gut mucosal barrier. Nonetheless, it appears that protein-malnourished mice are less able to clear translocating bacteria than normally nourished mice.