Inactivation of <i>aer</i> or <i>tsr</i> decreases numbers of <i>S.</i> Typhimurium in close proximity to the inflamed mucosal surface.

<p>Bovine ligated ileal loops (<i>N</i>: each inoculum was tested in loops from 4 different animals) were infected with an equal mixture of the indicated <i>S</i>. Typhimurium strains and samples collected 8 hours after infection from the luminal fluid and tissue punches (tissue-associated bacteria). (A) Bars represent geometric means of competitive indices (CI) ± standard error. (B) Fluid accumulation observed 8 hours after infection expressed as a percent of the response observed in loops infected with an equal mixture of the <i>S</i>. Typhimurium wild-type strain (AJB715) and a <i>tsr</i> mutant. Bars represent geometric means ± standard error. *, <i>P</i><0.05; ns, not significantly different.