A complete view of the genetic diversity of the Escherichia coli O-antigen biosynthesis gene cluster

Abstract

The O antigen constitutes the outermost part of the lipopolysaccharide layer in Gram-negative bacteria. The chemical composition and structure of the O antigen show high levels of variation even within a single species revealing itself as serological diversity. Here, we present a complete sequence set for the O-antigen biosynthesis gene clusters (O-AGCs) from all 184 recognized Escherichia coli O serogroups. By comparing these sequences, we identified 161 well-defined O-AGCs. Based on the wzx/wzy or wzm/wzt gene sequences, in addition to 145 singletons, 37 serogroups were placed into 16 groups. Furthermore, phylogenetic analysis of all the E. coli O-serogroup reference strains revealed that the nearly one-quarter of the 184 serogroups were found in the ST10 lineage, which may have a unique genetic background allowing a more successful exchange of O-AGCs. Our data provide a complete view of the genetic diversity of O-AGCs in E. coli showing a stronger association between host phylogenetic lineage and O-serogroup diversification than previously recognized. These data will be a valuable basis for developing a systematic molecular O-typing scheme that will allow traditional typing approaches to be linked to genomic exploration of E. coli diversity.

Escherichiacoli DERIVED FROM DIFFERENT SOURCES SHARE ANTIGENIC CHARACTERISTICS WITH Shigellaboydii 18AND VIRULENCE FACTORS WITH ENTEROTOXIGENIC E. coli

“…Together with the microagglutination tests, these results suggest that the 23 strains form a new sero-variety of E. coli. These results were similar to those from other studies that reported the presence of Shigella antigens in strains of E. coli (Navarro, 2010;Iguchi, 2011;Iguchi, 2015). Recently, Iguchi (2015) reported antigenic relationships between E. coli O38 and S. dysenteriae 8; E. coli O169 and O183 with S. boydii 6 and 10.…”

“…These results were similar to those from other studies that reported the presence of Shigella antigens in strains of E. coli (Navarro, 2010;Iguchi, 2011;Iguchi, 2015). Recently, Iguchi (2015) reported antigenic relationships between E. coli O38 and S. dysenteriae 8; E. coli O169 and O183 with S. boydii 6 and 10. Although 21 shared O antigens were recognized between E. coli and Shigella (Iguchi, 2015), in the case of S. boydii 18 no antigenic cross-reaction was observed with any other E. coli or Shigella somatic antigen (Liu, 2008).…”

“…Recently, Iguchi (2015) reported antigenic relationships between E. coli O38 and S. dysenteriae 8; E. coli O169 and O183 with S. boydii 6 and 10. Although 21 shared O antigens were recognized between E. coli and Shigella (Iguchi, 2015), in the case of S. boydii 18 no antigenic cross-reaction was observed with any other E. coli or Shigella somatic antigen (Liu, 2008). Previously, our laboratory reported E. coli strains isolated from three geographic zones with antigens from S. boydii 16 showing characteristics of ETEC (Navarro, 2010).…”

Bacteriophage-mediated Glucosylation Can Modify Lipopolysaccharide O-Antigens Synthesized by an ATP-binding Cassette (ABC) Transporter-dependent Assembly Mechanism

“…Significant progress has been made in establishing their precise structures and modes of assembly. As an example, there are more than 180 chemically and serotypically distinct glycans, giving rise to LPS O-antigens in Escherichia coli, and the structures, genes, and biosynthetic enzymes have been catalogued (1)(2)(3)(4). Diversity in glycoconjugate structures results from recombination events within genetic loci responsible for the synthesis of polysaccharides to generate a new structure and by acquisition of unlinked genes whose products modify existing structures.…”

Commentary: Whole-Genome Sequencing Data for Serotyping Escherichia coli—It's Time for a Change!

“…It is a freely available web tool that requires little or no expertise in bioinformatics to operate. The database was constructed using complete O and H antigen genes from the NCBI nucleotide collection, a comprehensive set of O antigen genes reported by Iguchi et al (8), and WGS of E. coli reference strains from the WHO Collaborating Centre for E. coli at the Statens Serum Institute, Copenhagen, Denmark. All database genes are compared against the genome of each test strain using the BLAST algorithm, and the output is the predicted O and H serotypes, based on the best-matching genes.…”