Opportunistic pathogen of mammalian intestinal tract. Bacteroides fragilis YCH46

Bacteroides fragilis strain YCH46. This organism can become an opportunistic pathogen, infecting anywhere in the body and causing abcess formation. Enterotoxigenic Bacterioides fragilis (ETBF) is associated with diarrheal diseases. This strain was isolated from a patient with septicemia in Japan. Virulence functions include numerous capsular polysaccharide biosynthesis systems that are controlled by invertible promoters that are recombined by a site-specific recombinase, Mpi, that works at a set of inverted repeats found within the chromosome. This system allows a vast repertoire of variable antigens to be expressed, thereby aiding evasion of the immune system. This organism also carries a potentially conjugative plasmid, as well as a number of conjugative and mobilizable transposons.