pagP基因对禽致病性大肠杆菌抗菌肽抗性和致病性的影响

【目的】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。pag P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pag P基因在APEC中的功能尚不清楚。本文构建禽致病性大肠杆菌pag P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pag P基因缺失株,然后利用回复质粒构建回复株。研究pag P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pag P基因缺失株和回复株,抗菌肽抗性试验发现pag P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(P0.01),致病性试验结果表明pag P基因缺失株的毒力显著降低(P0.01)。【结论】APEC的pag P基因对AVBD2的敏感性和APEC的致病性密切相关,为深入研究pag P基因的功能及调控作用奠定了基础。

Effects of pagP gene of avian pathogenic Escherichia coli on its antimicrobial peptide resistance and pathogenicity

Objective] Avian pathogenic Escherichia coli (APEC) leads to significant economic losses in poultry production, and affects public health. pagP gene plays key roles in pathogenicity and antimicrobial peptide resistance of bacteria. However, the function of pagP in APEC is still unknown. To determine the antibacterial peptide resistance and pathogenicity of pagP mutant strain, APEC pagP mutant strain was constructed. Methods] We constructed APEC-pagP mutant strain with red recombination system, and the corresponding complementary strain was also constructed. We detected the effects of PagP in cell adhesion and invasion, biofilm-forming ability, outer membrane permeability, antibacterial peptide sensitivity and pathogenicity. Results] pagP mutant strain and complementary strain were successfully constructed. The antimicrobial peptide resistance tests showed that pagP mutant strain was more sensitive to Polymyxin B and AVBD2 (P<0.01). The pathogenic test showed a significantly reduction of toxicity in pagP mutant strain (P<0.01). Conclusion] pagP gene in APEC played important roles in resistance to AVBD2 and pathogenicity in APEC.