Correlation between invasion of Caco-2 eukaryotic cells and colonization ability in the chick gut in Campylobacter jejuni

n an in vitro cell culture model using Caco-2 cells the adhesion and invasion properties of 11 Campylobacter (C.) jejuni isolates of different origin were studied. Additionally, we investigated the colonization ability of the strains in a chick model. Virtually, all C. jejuni showed cell adherence in the in vitro assay, but there were large differences in the invasion frequencies among the Campylobacter isolates. The colonization ability in the chick gut also differed markedly and enabled the formation of three groups: non-colonizing, weak or delayed colonization and strong colonization ability. On this occasion, we found a putative correlation between invasion of Caco-2 cells and colonization in the chick gut. Non-colonizers are not invasive or only have small invasion indexes. Strains which colonize weakly or exhibit delayed colonization have a medium invasion index and strong colonizers show markedly higher values of this parameter. The characterization of the flagellin gene of the used C. jejuni strains resulted in eight flaA types. There was no association between flaA type and invasion or colonization ability in the chick gut.