Evaluation of lactobacillus preparation on eterotoxigenic E. coli-induced rabbit ileal loop reactions

A commercially available lactobacillus-containing preparation has been used extensively in the treatment of diarrhea but few laboratory tests have been performed to determine the efficacy of this product. The rabbit ileal loop reaction was used here to determine the effect of the lactobacillus preparation and its ingredients on E. coli enterotoxin-induced loop fluid response. Enterotoxigenic E. coli cells grown overnight in shake cultures were washed and resuspended in saline to the original volume. They were then diluted in TSB suspensions of the lactobacillus preparation or its ingredients and injected into ileal loops. E. coli diluted in TSB served as positive controls. Fluid response was measured after 18 hours and the loop fluid ratio (LFR) (ml./cm.) of the lactobacillus preparations was compared to the positive controls. The positive controls always showed a high loop fluid ratio (greater than 1.1 ml./cm.) and negative saline controls showed no fluid response. The lactobacillus granules and tablets had low LFR's (0.08 and 0.05, respectively). Ingredients (whey, talc, sugar, evaporated milk, mineral oil) had variable LFR's (0.65, 0.78, 1.39, 1.46 and 1.54, respectively). Individual ingredients used to make this preparation show little antifluid response when used separately but the final product exhibits a significant antienterotoxin response.