Immediate effect of Lactobacillus acidophilus on the intestinal flora and fecal enzymes of rats and the in vitro inhibition of Escherichia coli in coculture

The in vitro role of Lactobacillus acidophilus was investigated to explore the potential to inhibit coliforms. A threefold concentrated cell-free extr act from L. acidophilus SBT2074 could efficiently inhibit most of the teste d Gram-positive and Gram-negative bacteria. Among the three strains of L. a cidophilus, SBT2062, SBT2071, and SBT2074, only L. acidophilus SBT2074 show ed this inhibitory property. These three strains were also tested in cocult ure with Escherichia coli 3544 in skim milk medium. The fermentation could result in complete inhibition of E. coli in 36 h. Short-term administration of L. acidophilus SBT2074 in rats with and without E. coli resulted in sig nificant inhibition of coliforms and anaerobes. The E. coli infected rats r egained the normal flora in the presence of lactic acid bacteria. The fecal enzyme beta-glucuronidase activity was also decreased significantly when L . acidophilus SBT2074 was administered and was related to the decreased num ber of bacteria in the intestinal tract. The analysis of the small intestin al contents showed that the concentrations of coliforms in the duodenum, je junum, and the ileum were significantly reduced by the administration of la ctic 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.