Rapid construction of Campylobacter jejuni deletion mutants

To develop a novel method for rapid construction of Campylobacter jejuni deletion mutants. We used overlapping extension PCR protocol to amplify a target sequence region of Camp. jejuni genomic DNA in which an internal fragment, Cj0618 coding sequence, was replaced by a chloramphenicol resistance cassette. After the resulting PCR product was introduced into electrocompetent Camp. jejuni 81-176, chloramphenicol-resistant mutants in which the wild type allele has been replaced by the deletion cassette were selected. DNA sequencing confirmed precise deletion in the Cj0618 gene. As expected from the previously reported role of Cj0618 in chick colonization, the resulting deletion mutant showed a caecal colonization defect in chick infection. This method can be used for rapid construction of Camp. jejuni deletion mutants. The use of this method should facilitate functional characterization of various Camp. jejuni genes.