INVITRO AND INVIVO ENZYMATIC-ACTIVITIES OF ANAEROBIC STRAINS RESPONSIBLE FOR COLONIZATION RESISTANCE TO CLOSTRIDIUM-DIFFICILE TOWARDS INTESTINAL MUCINS

We have proposed hamster intestinal microflora associated C3H axenic mice as an experimental model for studying the mechanisms of colonization resistance to C. d. and have isolated 3 anaerobe bacterial strains responsible for this effect. We have then shown that, from those strains, the reconstitution of the minimum active microflora in axenic mice is dependent on the type of the first inoculated strain. It was interesting to study the enzymatic activities of those strains towards mucin, considered as a substrate present in the digestive tract, potential active by way of modifications of its structure linked to the proteolytic and/or osidasic activities of the bacteria. Those enzymatic activities have been studied in vitro, in the presence of mucin, and in vivo, directly from the feces of the monoxenic, dixenic and trixenic mice. The first colonizing strain (C. indolis) has a partial enzymatic activity able to modify the mucin structure, which thus allows us to conclude that the complete mucin degradation needs the cooperation of the different strains. The second strain (C. cocleatum) is especially the most active. Those results have been confirmed by agarose and polyacrylamide gel electrophoresis of protein fecal extracts from monoxenic, dixenic and trixenic mice. The modifications of mucin induced by the enzymatic activities of the strains responsible for colonization resistance to C. d. could be implicated in the explanation of the mechanism of action of the microflora.