Comparison of host site colonization between hyperinfectious and conventionally virulent salmonellae following laboratory culture and animal passage.

<p>BALB/c mice were infected orally (10⁷ CFU) with hyperinfectious <i>S.</i> Choleraesuis χ3246 (boxes) or conventionally virulent <i>S.</i> Typhimurium reference strain 14028 (circles). These bacterial cells were derived from either stationary phase cultures containing LB medium (open symbols); or after in vivo passage (closed symbols), whereby 5 to 7 days post- oral infection, spleens were aseptically removed from acutely infected mice, and used, without ex vivo growth, to orally infect naïve animals. PP, Peyer's Patches; MLN, mesenteric lymph nodes; CFU, colony forming units. The symbols below the zero CFU value represent the number of mice in which the bacterial load was below the limits of detection: PP, MLN, spleen <40 CFU; Liver <20 CFU.