DNA rearrangements in the flagellin locus of an flaA mutant of Campylobacter jejuni during colonization of chicken ceca.

Campylobacter jejuni is an enteropathogen for humans but commensal for chickens. In both hosts, the flagella and motility are important colonization factors. The flagellin gene is duplicated in Campylobacter, but only one flagellin gene, flaA, is sufficient for motility. We found that, during colonization of the chicken intestine, a nonmotile flaA mutant of C. jejuni underwent rearrangements within its flagellin locus, thereby regaining its motility and colonization capacity. In contrast, in vitro motile revertants isolated from liquid culture showed different flagellin DNA rearrangements than after reversion in the chicken.