Expression by Lawsonia intracellularis of type III secretion system components during infection.

Contact-dependent secretion systems, such as the type III secretion system (T3SS), have been shown to play significant roles in the pathogenicity of many gram-negative bacterial pathogens. Lawsonia intracellularis is a novel, obligate intracellular gram-negative bacterium, which has been identified as the etiological agent of proliferative enteropathies in numerous animal species. Analysis of the genome sequence of the L.