ISOLATION AND IDENTIFICATION OF THE STRAINS RESPONSIBLE FOR THE COLONIZATION RESISTANCE TO CLOSTRIDIUM-DIFFICILE IN AN EXPERIMENTAL-MODEL - THE HAMSTER INTESTINAL MICROFLORA-ASSOCIATED AXENIC C3H MICE

Hamster conventional microflora is naturally resistant to C.d. colonization and it's now well known that most of antibiotics, especially clindamycin, can induce a Pseudo-membranous enterocolitis (P.M.C.). The study of the hamster intestinal microflora (H.I.M.) leads us to propose an experimental gnotobiotic animal model. We have first transferred the H.I.M. to C3H axenic mice. We have then verified that those mice possessed an intestinal microflora resistant to C.d. colonization and by the way of different treatments (Erythromycin by oral route - Heating the colon microflora at 70-degrees during 10 mn and transfer to axenic mice), we have obtained a simplified microflora resistant to C.d. colonization. From this simplified microflora and by the use of an anaerobic chamber, we have isolated 2 bacterial anaerobe strains belonging to the dominant flora. The first one is identified as Clostridium cocleatum and the second one is E.O.S and is supposed to belong to Clostridium species. Those 2 strains either alone or in association are unable to colonize the digestive tract of axenic mice. So we have isolated from suckling mice a third anaerobic strain identified as Clostridium indolis which is able to colonize the digestive tract of axenic mice. It has then been possible to transfer the two first isolated strains to those monoxenic mice. Those trixenic mice possess the minimum microflora necessary to exert the colonization resistance to C.d.