FIG. 7.
The Δppk1 mutant exhibits a dose-dependent defect for chick cecal colonization. Chicks were challenged orally with C. jejuni 81-176 wild type (▪) and the Δppk1 mutant (▿), using doses of 1.5 × 105, 1.5 × 106, and 1.5 × 107 CFU in 0.5 ml of broth. After 7 days postinfection, chicks were sacrificed, and bacterial colonization of ceca was determined by plating on Karmali agar. Levels of colonization at specific doses are expressed as CFU/g of cecal content. The detection limited was 40 CFU. Each data symbol represents CFU recovered from an individual chick. The geometric mean of bacterial concentration recovered is represented by a bar for each dosage.