Comparative analysis of flagellin sequences from Escherichia coli strains possessing serologically distinct flagellar filaments with a shared complex surface pattern

Abstract

ence of both serotype-specific determinants (3,16,19,20,39,43,60) and cross-reactive determinants (1,3,5,12,13,26,43). The immunological relationships among morphotype E flagellins have been analyzed by using monoclonal antibodies (43,60). In addition to serotype-specific and broadly cross-reactive epitopes, other epitopes were common among subgroups of closely related flagellin serotypes within morphotype E. Immunogold labeling studies demonstrated that serotype-specific determinants tend to be surface exposed in intact flagellar filaments, while cross-reactive determinants tend to be hidden (43,60).DNA sequence analysis of flagellin structural genes from E. coli K-12 (24), Serratia marcescens (10), and several Salmonella serovars (15,48,58,59) demonstrated that the termini of flagellin proteins are conserved. The central region of the flagellin molecule is variable and gives rise to serotype-specific epitopes (6,16,18,19,23,36,45,47,48,58). The flagellin protein therefore possesses several distinct structural domains (34,46,(51)(52)(53)(54)56). These have been mapped on the primary structure of the flagellin molecule and localized within the intact flagellar filament by electron density mapping studies (57). The conserved, terminal regions of flagellin were found to be associated with the inner structure of intact flagellar filaments. The outer surfaceexposed architecture is formed from the folding outward of 5395

Identification of putative new Escherichia coli flagellar antigens from human origin using serology, PCR-RFlP and DNA sequencing methods

“…The flagellin proteins are conserved in their terminal domains, whereas, the central domain is variable and carries serotype-specific epitopes. 6 Flagellin genes are suitable for PCR amplification, and variability between the PCR products can subsequently be assessed by restriction analysis (PCR-RFLP) or DNA sequencing. 1,3,7 Molecular biology techniques offer the potential for rapid and reproducible analysis of bacterial diversity.…”

PCR for Specific Detection of H7 Flagellar Variant of fliC among Extraintestinal Pathogenic Escherichia coli

“…Supporting this conclusion were the uniform HincII and RsaI RFLP profiles obtained for H7 fliC amplicons irrespective of clonal origin. Cross-lineage conservation of the H7 fliC variant has been suggested previously by the high level of nucleotide identity between H7 fliC variants from E. coli O157:H7 and O55:H7, E. coli O1:H7, and E. coli O128:H7 (9,29,31) and the ability of H7-specific primers to generate fliC amplicons from H7-positive strains of diverse O types (9). However, the only published direct evidence of conservation of fliC across phylogenetic boundaries involved a single O128:H7 diarrhea isolate (DEC 13a), in comparison with multiple E. coli O157:H7 diarrhea isolates (29,36).…”

“…These include E. coli O1:K1:H7 and O2:K1:H7, serotypes traditionally associated with pyelonephritis and sepsis (16,21,27), and E. coli O18:K1:H7, a serotype traditionally associated with neonatal bacterial meningitis and neonatal sepsis but recently shown to be highly prevalent also in uncomplicated cystitis in adult women (1,4,12,15,21,22). Although an E. coli O1:H7 isolate (strain U5-41) actually was the source of the first published H7 fliC sequence (31), all three studies of PCR-based detection of the H7 fliC variant have focused on diarrheagenic E. coli, with scant attention given to ExPEC (8,9,25). In these studies the only putative ExPEC isolates examined were of serotypes O1:H7 and O18: H7.…”

“…The H7 flagellar variant of Escherichia coli recently has received increasing attention because of its diagnostic importance with respect to E. coli O157:H7 (8,9,25,29,31), the major cause of hemorrhagic colitis and hemolytic-uremic syndrome in the industrialized world (6,32,33). Inconsistent expression of the H7 antigen and the technical difficulties associated with H antigen serotyping have led to interest in PCR-based assays for detection of the H7 allele of the E. coli flagellin gene, fliC (8,9,25).…”

“…H7 primers were selected based on the published fliC sequence from E. coli O1:H7 strain U5-41 (GenBank accession no. L07388) (31), in comparison with other sequenced fliC variants (29,31). Selection criteria for H7 specificity included (i) location within the internal variable region of fliC, (ii) conservation among all sequenced H7 fliC variants (29), and (iii) absence of homology with known non-H7 fliC variants.…”