Characterization of an Escherichia coli O157:H7 O-antigen deletion mutant and effect of the deletion on bacterial persistence in the mouse intestine and colonization at the bovine terminal rectal mucosa

Escherichia coli O157:H7 mutant defective in the synthesis of the lipopolysaccharide side chain (O antigen) by deletion of a putative perosamine synthetase gene (per) in the rfb cluster was generated to study the role of the O antigen in persistence and colonization in the animal host. The data results suggested that the O polysaccharide side chain of Escherichia coli O157:H7 lipopolysaccharide (LPS) is a required factor for efficient bovine intestinal colonization.