Abstract: Objective To construct enterohemorrhagic Escherichia coli (EHEC) O157: H7 ppk gene deletion strains and study its
biological characteristics. Methods The gene fragment of kanamycin resistance was amplified using a pair of homologous arm
primers whose 5’ and 3’ ends were homologous with ppk gene and kanamycin resistance gene, respectively. EHEC O157: H7
EDL933w competent strains were prepared and transformed via electroporation with the amplification products. The ppk gene
was replaced by kanamycin resistance gene using pKD46-mediated Red recombination system. The recombinant strain was
confirmed by PCR and sequencing, and its morphology, growth ability and adhesion were assessed using Gram staining, OD600
value and Giemsa staining. Results and Conclusion We established a ppk-deleted EHEC O157:H7 EDL933w strain with
kanamycin resistance and compared the biological characteristics of the wild-type and mutant strains, which may facilitate
further study of the regulatory mechanism of ppk gene.