title: Bacteroides spp. and diarrhea.
abstract: OBJECTIVE
  The purpose of this review is to describe recent progress in the understanding of the role of Bacteroides spp. in human diarrheal diseases and newer murine studies implicating certain Bacteroides spp. in colorectal cancer.
  
  
  RESULTS
  Bacteroides fragilis is the only strain of Bacteroides spp. associated with diarrheal disease. Toxin-producing strains of B. fragilis, termed enterotoxigenic Bacteroides fragilis (ETBF), are an established cause of diarrheal disease in people. The clinical syndrome associated with ETBF diarrheal disease encompasses abdominal pain, tenesmus and inflammatory diarrhea. Two new studies conducted in mice have further defined the chronic inflammatory response associated with ETBF infection and observed that in the multiple intestinal neoplasia mouse strain, heterozygotes for the adenomatous polyposis coli gene, ETBF infection enhances development of colonic tumors. Separate murine studies have begun to define the role of nontoxin-producing B. fragilis as a symbiont, serving possibly to protect the host from colonic inflammation.
  
  
  CONCLUSIONS
  B. fragilis remains the leading anaerobe in human disease. ETBF is emerging as an important cause of human diarrheal disease but additional epidemiologic studies are needed to better understand the role of ETBF human disease.
authors.affiliation: Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Wick
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Sears
mesh_terms: D025601:Adenomatous Polyposis Coli Protein / Q000235:genetics; D000818:Animals; D001427:Bacterial Toxins / Q000633:toxicity; D001442:Bacteroides Infections / Q000473:pathology*; D001441:Bacteroides fragilis / Q000472:pathogenicity*; D015179:Colorectal Neoplasms / Q000382:microbiology; D003967:Diarrhea / Q000382:microbiology*; D004195:Disease Models, Animal; D020022:Genetic Predisposition to Disease; D006801:Humans; D051379:Mice; D011110:Polymorphism, Genetic; D037521:Virulence Factors / Q000633:toxicity
chemical_list: D025601:Adenomatous Polyposis Coli Protein; D001427:Bacterial Toxins; D037521:Virulence Factors