ANTIGENIC CHARACTERISTICS OF ENTEROTOXIGENIC AND NONENTEROTOXIGENIC ISOLATES OF BACTEROIDES-FRAGILIS

  • 1 April 1987
    • journal article
    • research article
    • Vol. 48  (4) , 643-645
Abstract
Fecal isolates of enterotoxigenic (44 isolates) and non-enterotoxigenic (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.