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【背景】禽致病性大肠杆菌(Avian Pathogenic Escherichia Coli,APEC)不仅严重影响全球的养禽业,对人类公共健康也造成巨大的潜在威胁。pagP基因在细菌的抗菌肽抗性和致病性方面发挥重要作用,但关于pagP基因在APEC中的功能尚不清楚。【目的】构建禽致病性大肠杆菌pagP基因缺失株,对缺失株的抗菌肽抗性和致病性进行研究。【方法】利用Red重组系统构建APEC的pagP基因缺失株,然后利用回复质粒构建回复株。研究pagP基因对细胞黏附与入侵、生物被膜形成能力、外膜渗透性、抗菌肽敏感性、致病性等方面的影响。【结果】成功构建pagP基因缺失株和回复株,抗菌肽抗性试验发现pagP基因缺失株对多粘菌素B、鸡β-防御素2(AVBD2)的敏感性显著增加(P<0.01),致病性试验结果表明pagP基因缺失株的毒力显著降低(P<0.01)。【结论】APEC的pagP基因对AVBD2的敏感性和APEC的致病性密切相关,为深入研究pagP基因的功能及调控作用奠定了基础。
【Background】 Avian Pathogenic Escherichia Coli (APEC) not only seriously affects the global poultry industry, but also poses a great potential threat to human public health. The pagP gene plays an important role in the antibacterial peptide resistance and pathogenicity of bacteria, but the function of pagP gene in APEC is unclear. 【Objective】 To construct the pagP gene deletion strain of avian pathogenic Escherichia coli and study the antibacterial peptide resistance and pathogenicity of the deletion strain. 【Method】 The APEC pagP gene deletion strain was constructed by using the Red recombination system, and then the replicative plasmid was used to construct the replicon strain. To study the effect of pagP gene on cell adhesion and invasion, biofilm formation ability, permeability of outer membrane, antibacterial peptide sensitivity and pathogenicity. 【Results】 The pagP gene deletion and recovery strains were successfully constructed. The antimicrobial peptide resistance test showed that the pagP gene deletion strains had significantly increased sensitivity to polymyxin B and chicken β-defensin 2 (AVBD2) (P <0.01) The pathogenicity test results showed that the virulence of the pagP gene deletion strain was significantly reduced (P <0.01). 【Conclusion】 The sensitivity of APEC pagP gene to AVBD2 is closely related to the pathogenicity of APEC, which lays the foundation for further study on the function and regulation of pagP gene.