Influence of HtrA on C. jejuni colonization along the intestinal tract of infant mice. (A) Loading control (Coomassie blue staining) of proteins from total cell lysates (top) and Western blot for the expression of HtrA in the two C. jejuni strains used in this infection study. (B) Immediately after weaning, conventional infant wild-type mice were perorally infected with C. jejuni NCTC11168 (WT, closed circles) or the mutant strain NCTC11168∆htrA (∆htrA, open circles). The pathogenic loads in distinct compartments of the intestinal tract were determined by quantification of live C. jejuni in luminal samples taken from duodenum, ileum, and colon at day 7 following infection by cultural analysis (CFU, colony forming units). Medians (black bars) are indicated and numbers of mice harbouring the respective C. jejuni strain out of the total numbers of analyzed animals are given in parentheses. Data shown were pooled from three independent experiments.