Wt and Δrex strains in an oral listeriosis model 1, 2, and 4 days post-infection.

Female BALB/c mice were orally infected with 10⁸ CFU of wt (black squares) or Δrex (blue circles) and the number of bacteria present in each tissue was determined over time. A-F. Mice were sacrificed on 1, 2, and 4 days post-infection and organs were harvested to enumerate bacterial burden. Panel A includes small intestinal tissue only; bacterial burden in the intestinal contents was not evaluated. Each symbol represents an individual mouse (n = 3 per group) and the solid lines indicate the geometric means. Dashed lines indicate the limit of detection (l.o.d.). Results are expressed as log-transformed CFU per organ or per gram of feces. p values were calculated using a heteroscedastic Student’s t test. * p < 0.05; *** p < 0.001.

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