ABSTRACT
Objective To construct EHEC△z5150 using Red recombination and explore its pathogenicity.Methods Overexpression of the z5150 gene was used to test its toxicity.The kanamycin resistant gene flanked by homologues of target genes was amplified by PCR before being transferred into EHEC containing pKD 46 plasmid,and the target fragments were recombined into genome by Arabia sugar.The kanamycin resistance gene was removed by pFLP 2 plasmid mediated FLP site-specific recombination.Cell adhesion ability and virulence of the mutant were detected by infecting HT 29 cells and BALB/c female mice,respectively.Results and Conclusion The mutant strain EHEC △z5150 was successfully constructed.The absence of z5150 did not affect the normal growth of bacteria,but after excessive expression,it inhibited the growth.Deletion of z5150 showed significant difference in intestinal epithelial cell adhesion and pathogenicity compared with wild strain.This study provides a gene knockout technique for the study of EHEC gene function and of the relationships between RelEz5150 and EHEC pathogenicity.