title: Antigenic characteristics of enterotoxigenic and nonenterotoxigenic isolates of Bacteroides fragilis.
abstract: Fecal isolates of enterotoxigenic (44 isolates) and nonenterotoxigenic (25 isolates) Bacteroides fragilis were obtained from diarrheic calves (62 isolates), lambs (2 isolates), and pigs (5 isolates). Using a Microtiter whole-cell agglutination test and gel double-diffusion analysis, the isolates were reacted with nonabsorbed rabbit antisera prepared against 13 isolates of enterotoxigenic B fragilis (ETBF). Isolates of B fragilis were antigenically diverse. Thirty-seven (84%) of the 44 isolates of ETBF comprised 13 serogroups on the basis of reaction in the agglutination test. Fourteen (56%) of the 25 isolates of non-ETBF comprised 4 of the 13 groups. Compared with results of the gel-diffusion test, most isolates had a different agglutination test reaction pattern against the 13 antisera. Isolates of ETBF could not be distinguished from non-ETBF. Antigenic heterogeneity of B fragilis facilitated differentiation of individual isolates, a capability that may be useful in future epidemiologic and virulence studies.
mesh_terms: D000372:Agglutination Tests; D000818:Animals; D000942:Antigens, Bacterial / Q000032:analysis*; D001442:Bacteroides Infections / Q000382:microbiology / Q000662:veterinary*; D001441:Bacteroides fragilis / Q000145:classification / Q000276:immunology* / Q000472:pathogenicity; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology; D003967:Diarrhea / Q000382:microbiology / Q000662:veterinary*; D004768:Enterotoxins / Q000096:biosynthesis; D005779:Immunodiffusion; D011817:Rabbits; D012703:Serotyping; D012756:Sheep; D012757:Sheep Diseases / Q000382:microbiology; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology
chemical_list: D000942:Antigens, Bacterial; D004768:Enterotoxins