HIGHLIGHT RESULTS: PROPATH Project Co-ordinator: Prof. Luc De Vuyst ( ldvuyst@vub.ac.be)

1. HIGHLIGHT RESULTS: PROPATH Project Co-ordinator: Prof. Luc De Vuyst (ldvuyst@vub.ac.be) • The inhibitory activity of bifidobacteria towards Gram-negative, gastrointestinal pathogens is solely due to the production of organic acids, in particular acetic acid and lactic acid. Prebiotic inulin-type fructans might modulate the production of organic acids by lactobacilli and bifidobacteria in the gastrointestinal tract, underlying their potential activity towards pathogenic bacteria. • Lactic acid has an important role in the activity of lactobacilli against Salmonella Typhimurium. Certain lactobacilli produce heat-stable, non-proteinaceous, specific, anti-Salmonella compounds, which are active at low pH and in the presence of lactic acid. 3) Lactobacillus johnsonii La1 produces a bacteriocin, named lactacin Fa, inhibitory to lactobacilli. The anti-H. pylori activity probably consists of or is depending on a mixture of low-molecular-mass metabolites and/or protease-sensitive compounds/bacteriocin(s). 4) Lactobacillus johnsonii La1, Lactobacillus casei Shirota, and Lactobacillus amylovorus DCE 471 significantly decrease H. pylori binding to cultured human gastric adenocarcinoma AGS cells. Administration of Lb. johnsonii La1 to mice results in a significant delay of both chronic and chronic-active gastritis. 5) Some lactobacilli such as Lactobacillus johnsonii La1, Lactobacillus casei Shirota, and Lactobacillus plantarum ACA-DC 287 strongly inhibit the invasion of S. Typhimurium SL1344 into cultured human enterocyte-like Caco-2 cells. Reduced S. Typhimuriumlevels are observed in the gastrointestinal tract and tissues of Salmonella-infected mice after administration of cultures of Lb. casei Shirota and Lb. fermentum ACA-DC 179.