ASSOCIATIONS BETWEEN HEAT-STABLE (0) AND HEAT-LABILE (HL) SEROGROUP ANTIGENS OF CAMPYLOBACTER-JEJUNI - EVIDENCE FOR INTERSTRAIN RELATIONSHIPS WITHIN 3 O HL SEROVARS/

A comparative examination of the heat-stable (O) and heat-labile (HL) serogrouping results for 9,024 sporadic human isolates of Campylobacte r jejuni revealed conserved associations between specific O and HL ant igens (O/HL serovars), Forty-nine percent of the isolates which groupe d for both O and HL antigens belonged to one of three serovars: O 4 co mplex/HL 1 (17.9%), O 1/HL 2 (16.8%), or O 50/HL 7 (14.5%), Other comm on serovars were O 2/HL 4 (8.3%), O 6/HL 6 (8.1%), O 53/HL 11 (4.5%), O 19/HL 17 (3.3%), O 5/HL 9 (3.3%), O 9/HL 9 (3.2%); and O 23/HL 5 (3. 1%). These 10 serovars accounted for 83.1% of the serogroupable isolat es. A large number of strains (41.3%) could be typed by only one of th e two methods or could not be serogrouped (11%), Strains belonging to three serovars, O 2/HL 4, O 50/HL 7, and O 23/HL 5, were further chara cterized by combining data from expressed features (O/HL serogroups, p hage groups, and biotypes) with restriction fragment length polymorphi sm genotypes, These polyphasic data demonstrated that within each sero var, individual isolates showed substantial conservation of both genom ic and phenotypic characteristics. The essentially clonal nature of th e three serovars confirmed the potential of combined O and HL serogrou ping as a practical and phylogenetically valid method for investigatin g the epidemiology of sporadic C,jejuni infection.