ppk1 gene relates with the pathogenesis of meningitis infected by E. coli K1

Abstract:

[Objective] To construct the polyphosphate kinase 1 gene deletion mutant of Escherichia coli (E. coli) K1 strain E44 and explore the role of ppk1 in the pathopoiesis of meningitis E. coli K1. [Methods] The ppk1 gene was knocked out from the genome of E. coli K1 strain E44 by using suicide vetor pCVD442 and homologous recombination, and the mutant was named Δppk1. Then the survival ablities of E44 and Δppk1 in poor nutrition condition and oxidative stress were examined. The ability of the mutant adhering to human brain microvascular endothelial cells (HBMEC) was also compared with that of the wild type. The cytogenetic toxic effects induced by Δppk1 and E44 were tested by using the lactic dehydrogenase testing kit. [Results] The ppk1 gene of the mutant had been knocked out and was confirmed by PCR and DNA sequencing. The ppk1 deletion mutant showed to be defective in adhesion ability to HBMEC and survival abilities under poor nutrition condition and oxidative stress. The damaging effects of HBMEC induced by Δppk1 were significantly less than that induced by E44. [Conclusion] The ppk1 gene plays an important role in E. coli K1 surviving in low nutrition and oxidative stress condition, adhering to HBMEC and inducing cell injury.