A novel microorganism of the genus Bifidobacterium longum, in particular to its genomic and plasmid sequence and to a method of producing polypeptides of said Bifidobacterium, respectively. Also methods of detecting these nucleic acids or polypeptides, respectively. A data carrier is provided comprising nucleotide sequences and/or polypeptide sequences of NCC2705. In addition, the Bifidobacterium longum strain NCC2705 and also to food and pharmaceutical compositions containing said Bifidobacterium or active components thereof for the prevention and/or treatment of diarrhoea brought about by rotaviruses and pathogenic bacteria are provided.