Mutation of waaN reduces Salmonella enterica serovar Typhimurium-induced enteritis and net secretion of type III secretion system 1-dependent proteins.

Mutation of waaN, a gene involved in lipid A biosynthesis, reduced enteropathogenic responses induced by Salmonella enterica serovar Typhimurium in bovine ligated ileal loops. However, the secretion of key virulence determinants was also reduced, and therefore the reduction in enteropathogenicity cannot be solely attributed to a reduction in biological activity of lipid A.