ETUDE D’UNE ADHESINE IDENTIFIEE CHEZ RUMINOCOCCUS GNAVUS E1

Ruminococcus gnavus E1 is a Gram positive strict anaerobic bacterium that was isolated from the dominant faecal microbiota of a healthy adult. A 6kb-long open reading fragment called radA was identified on the E1 chromosome, next to the genetic clusters involved in the biosynthesis of the RumA and RumC bacteriocins which are active against pathogenic Clostridium perfringens. radA shares a high sequence homology with genes of Staphylococcus aureus, Bacillus cereus and C. perfingens encoding adhesins of the MSCRAMMs family. RT-PCR experiments demonstrated that the radA gene was strongly expressed in vivo, when the E1 strain colonized the digestive tract of monoxenics animals, while little transcription occured in vitro. These results suggest that RadA could play an important role in the colonization of the digestive ecosystem.