Immediate Effect of Lactobacillus acidophilus on the Intestinal Flora and Fecal Enzymes of Rats and the In Vitro Inhibition of Escherichia coli in Coculture

Abstract

The in vitro role of Lactobacillus acidophilus was investigated to explore the potential to inhibit coliforms. A threefold concentrated cell-free extract from L. acidophilus SBT2074 could efficiently inhibit most of the tested Gram-positive and Gram-negative bacteria. Among the three strains of L. acidophilus, SBT2062, SBT2071, and SBT2074, only L. acidophilus SBT2074 showed this inhibitory property. These three strains were also tested in coculture with Escherichia coli 3544 in skim milk medium. The fermentation could result in complete inhibition of E. coli in 36h. Short-term administration of L. acidophilus SBT2074 in rats with and without E. coli resulted in significant inhibition of coliforms and anaerobes. The E. coli infected rats regained the normal flora in the presence of lactic acid bacteria. The fecal enzyme β-glucuronidase activity was also decreased significantly when L. acidophilus SBT2074 was administered and was related to the decreased number of bacteria in the intestinal tract. The analysis of the small intestinal contents showed that the concentrations of coliforms in the duodenum, jejunum, and the ileum were significantly reduced by the administration of lactic acid bacteria. The effects are seen in a short period, suggesting that L. acidophilus SBT2074 fermentate may have clinical application for people suffering from gastrointestinal distress caused by coliforms.