Correlation of an expanded direct fluorescent-antibody system with an established passive hemagglutination system for serogrouping strains of Campylobacter jejuni and Campylobacter coli

Abstract

Rabbits were inoculated with whole, formalinized cells from 8 passive hemagglutination reference strains of Campylobacter. Fluorescein isothiocyanate-labeled IgG from these antisera defined 7 new direct fluorescent-antibody serogroups of C. jejuni and 1 new serogroup of C. coli [C. fetus and C. coli are both formally known as C. fetus ssp. jejuni]. This expanded the Campylobacter direct fluorescent antibody system to include 17 serogroups of C. jejuni, 3 serogroups of C. coli and 2 serogroups of C. fetus. The passive hemagglutination method (57 serotypes) and the direct fluorescent-antibody method (20 serogroups) were compared for typing strains of C. jejuni and C. coli. The data obtained by testing 101 strains by both methods revealed that the 2 test systems were measuring completely different sets of antigen complexes. The 2 serogrouping methods were complementary; their combined use discriminated among strains more effectively than did either method individually.