title: Evaluation of the pathogenicity of the Bacteroides fragilis toxin gene subtypes in gnotobiotic mice.
abstract: Enterotoxigenic Bacteroides fragilis (ETBF) strains produce a metalloprotease toxin (BFT) related to diarrheal disease in animals, young children, and adults. Three different isoforms of the enterotoxin, designated BFT-1, BFT-2, and BFT-3, have been identified and sequenced. In the present study, the pathogenicity of the ETBF strains carrying bft-1 or bft-2 was evaluated. Each toxin gene subtype of ETBF (bft-1 or bft-2) was intragastrically monoassociated to germ-free mice during 10 days and histopathological data from intestines and liver compared with those from mice monoassociated to a non-enterotoxigenic B. fragilis. Histopathological alterations were observed in all groups of animals related to ETBF. These alterations were characterized mainly by ulceration, edema, and inflammatory infiltration in intestine. However, these lesions were slightly more severe in mice monoassociated with bft-2 subtype. No alteration or lesion was observed in animals associated with the non-enterotoxigenic B. fragilis. In conclusion, strains harboring bft-1 or bft-2 gene subtypes were able to induce histopathological alterations in intestine of a gnotobiotic mice model and it could explain the effect produced for the enterotoxin.
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Viviane
authors.initials: V
authors.lastname: Nakano
authors.forename: Danielle A
authors.initials: DA
authors.lastname: Gomes
authors.forename: Rosa M E
authors.initials: RM
authors.lastname: Arantes
authors.forename: Jacques R
authors.initials: JR
authors.lastname: Nicoli
authors.forename: Mario J
authors.initials: MJ
authors.lastname: Avila-Campos
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000235:genetics* / Q000633:toxicity*; D001442:Bacteroides Infections / Q000382:microbiology*; D001441:Bacteroides fragilis / Q000302:isolation & purification / Q000472:pathogenicity*; D002648:Child; D002675:Child, Preschool; D003967:Diarrhea / Q000382:microbiology; D004487:Edema / Q000382:microbiology; D004768:Enterotoxins / Q000235:genetics / Q000633:toxicity; D005856:Germ-Free Life; D006801:Humans; D008666:Metalloendopeptidases / Q000235:genetics* / Q000633:toxicity*; D051379:Mice
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; C405031:Bacteroides fragilis toxin; D008666:Metalloendopeptidases