Campylobacter coli strains with enlarged flagellin genes isolated from river water

A group of campylobacters isolated from river water were found to possess u nusually large flagellin genes. Both phenotype and serology were consistent with identification as Campylobacter coli. Phylogenetic analysis of small (16S, rus) and large subunit (23S, rrl) rRNA genes of a representative stra in, NCTC 13006, demonstrated high levels of relatedness with C. jejuni and C. coli (99.1 and 98.3% similarity for 16S; 99.3 and 99.4% similarity for 2 3S). Large flagellin proteins were demonstrated by SDS-PAGE analysis. The f laA and flaB genes were sequenced and aligned with known campylobacter flag ellin amino acid sequences. The encoded FlaA protein of the new group exhib ited a high degree of divergence from other Campylobacter species. Within t he central variable region of maA, a further hypervariable domain was ident ified containing characteristic repeated motifs. Separate pairwise alignmen ts performed for the variable regions of the polypeptide indicated these la rge fla genes were more closely related to those of C. upsaliensis than to those of C. coli or C. jejuni. (C) Elsevier, Paris.