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Published on: September 1, 2018
Deletion of the Escherichia coli O14:K7 O antigen gene cluster
Slade O Jensen1, Peter R Reeves
1School of Molecular and Microbial Sciences, University of Sydney, New South Wales, Australia.
Abstract:
Escherichia coli O14:K7 is a rough strain, lacking a typical O antigen, in which the enterobacterial common antigen is attached to the lipopolysaccharide core. The rough phenotype was previously mapped to the O antigen gene cluster; however, the nature of the nonfunctional locus was not defined. In this study, we have shown that the O antigen gene cluster of an O14:K7 type strain (Su4411/41) was most likely deleted via homologous recombination between the GDP-mannose pathway genes (manB and manC) of the colanic acid and O antigen gene clusters. A similar recombination event has previously been inferred for the deletion of E. coli Sonnei chromosomal O antigen genes. Therefore, recombination between the GDP-mannose pathway genes provides a convenient mechanism for the deletion of O antigen genes, which may occur if the typical O antigen becomes redundant.

