jejuni strains differed in their ability to colonize and cause enteritis in C57BL/6 IL-10-/- mice in the initial passage of experiment 2 (serial passage experiment) Mice were infected with total doses of ~1 × 1010 cfu C. jejuni, housed individually for 30–35 days, and then

euthanized and necropsied as previously described [40]. C. jejuni cells in wet mounts of all suspensions used to inoculate mice were highly motile. Mice were evaluated twice daily for clinical signs of disease and euthanized promptly if severe clinical signs were observed. Fecal samples were taken on days 3 or 4, 9 or DAPT in vitro 10, and at necropsy and spread on medium selective for C. jejuni (Figure 2). Additional detailed colonization data are presented in Additional file 1 (Additional file 1, Table S1). As shown in the summary in Table 3, five of the seven strains

were able to colonize the mice;C. jejuni could be cultured from the feces of 5/5 mice inoculated with strains 11168, D0835, D2586, D2600, and NW on all days of sampling and from tissue and fecal samples obtained at necropsy (Figure 2; Additional file 1, Table S1). Strains 33560 and D0121 were never mafosfamide recovered by culture from selleckchem fecal samples taken during the course of infection (data not shown) or from tissues or feces collected at necropsy (Additional file 1, Table S1). Strain 33560 DNA was present at low levels in multiple tissues collected at necropsy as shown by PCR assay for the C. jejuni gyrA gene [44] performed on DNA extracted from tissues, but strain D0121 was only weakly detected in two tissue

samples by PCR assay (Additional file 1, Table S1). Cultures were verified using the same PCR assay. Figure 2 Culturable fecal populations of colonizing C. jejuni strains in C57BL/6 IL-10 -/- mice (experiment 2). Levels of growth on TSA-CVA agar medium were scored on a scale of 0 to 4 (0, no colonies; 1, ≤ ~20 colonies; 2, ~20–200 colonies; 3, ≥ ~200 colonies; 4, confluent growth). C. jejuni was not recovered by culture from mice inoculated with tryptose soya broth or with non-colonizing strains 33560 and D0121 at any time. Each point represents an individual mouse. Table 3 Initial ability of C. jejuni strains to colonize and cause enteritis in C57BL/6 IL-10-/- mice. C. jejuni strain C. jejuni detectable by culture; culture verified by PCR C.