Construction of uropathogenic Escherichia coli strain with ppkl gene deletion and study on its biolog-ical properties

Abstract

Objective To construct a Polyphosphate kinase 1 （ppk1） gene deletion mutant of uro- pathogenic Escherichia coli （E. coli） cFT073, and to explore the biological properties of the mutant strain. Methods The ppk1 gene deletion strain （ △ pk1 ） was constructed based on CFT073 E. coli strain by using grad homologous recombination technology. A comparison analysis was conducted on adhesive and invasive abihties between CFT073 wild type strain and △pk1 strain in in vitro madel of human bladder cancer epithe- lial cell 5637. Crystal violet staining method was used to evaluate the influences of ppk1 gene deletion on biofilm formation. Results The CFT073 ppk1 deletion mutant strain was successfully constructed. Com- pared with the wild type strain, Apk1 strain showed impaired adhesive and invasive abilities to 5637 cells. Moreover, the absorbance values of crystal violet at 570 nm at each time point of the mutant strain group were also lower than those of the wild-type strain group. Conclusion The ppk1 gene deletion mutant of uro- pathogenic E. coil CFT073 could be successfully constructed by Red homologous recombination technology and its biological properties indicates that ppk1 gene plays an important role in the pathogenesis of uropatho- genic E. coli infection through regulating the abilities of adhesion, invasion and biofilm formation. Key words: Urinary tract infection; Escherichia coli; Gene knockout; Polyphosphate kinase 1