Two Methods to Inactivate Capsule Synthesis genes in Campylobacter jejuni

Capsule polysaccharide (CPS) is an essential virulent determinant expressed by some pathogenic bacteria. Objective: The aim of this study was to inactivate Campylobacter jejuni kps genes, which are involved in the transport of the CPS molecules through the membrane. Method: To obtain kps mutants two different approaches were employed. Both inverse-PCR and the neighbour-joining method were used to construct a suicide vector, which carries a kanamycin resistance gene inserted into the bacterial DNA fragment encoding the kps gene. Results: This study found that both techniques were successfully used in constructing a suicide vector. Even though the neighbour-joining technique involves more steps, it can be recommended as the preferred method if the cloning vector is large, as this may be difficult to amplify by PCR. The suicide vectors were used to naturally transform a C. jejuni strain, which after homologous recombination resulted in a kanamycin resistant mutant. Conclusion: This study found that both inverse-PCR and the neighbour-joining technique could be used to inactivate genes in C. jejuni.