title: Novel ecological niche of Cetobacterium somerae, an anaerobic bacterium in the intestinal tracts of freshwater fish.
abstract: OBJECTIVE
  This study was conducted to clarify the taxonomic status of Bacteroides type A strains with high vitamin B(12)-producing ability that is widely distributed in the intestinal tracts of freshwater fish.
  
  
  RESULTS
  Seventeen strains of Bacteroides type A isolated from five fish species were all rod-shaped and gram-negative. The strains were positive for esculin hydrolysis, nitrate reduction, resistance to bile, acid phosphatase, and negative for the production of catalase and urease and the susceptibility to vancomycin. The G+C content of DNA from the 17 strains was 29 x 1-31 x 9 mol%, and 16S rDNA sequence analysis revealed a close phylogenetic relationship between Bacteroides type A strains and Cetobacterium somerae sharing 99 x 7-100% sequence similarity. In addition, strains were capable of producing vitamin B(12) at a rate of 1 x 82-13 x 98 ng ml(-1) in 48 h.
  
  
  CONCLUSIONS
  Phenotypic and phylogenetic characteristics indicated that all isolates previously classified as Bacteroides type A strains belong to C. someare.
  
  
  CONCLUSIONS
  This study provided the important finding of novel niche of vancomycin-resistant bacteria such as C. somerae in the intestinal tract of freshwater fish.
authors.affiliation: Department of Marine Science and Resources, Nihon University, Kameino, Fujisawa, Kanagawa, Japan.
authors.forename: C
authors.initials: C
authors.lastname: Tsuchiya
authors.forename: T
authors.initials: T
authors.lastname: Sakata
authors.forename: H
authors.initials: H
authors.lastname: Sugita
mesh_terms: D000818:Animals; D001439:Bacteroides / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D001482:Base Composition; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D005399:Fishes / Q000382:microbiology*; D005618:Fresh Water; D045182:Fusobacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D007422:Intestines / Q000382:microbiology*; D007564:Japan; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D014805:Vitamin B 12 / Q000096:biosynthesis
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D014805:Vitamin B 12