lpxL和lpxM基因对O1、O78血清型禽致病性大肠杆菌毒力的影响  

Effect of lpxL and lpxM genes on virulence of avian pathogenic Escherichia coli belonging to O1 and O78 serogroups

作　　者：屈香 杨梓纯 许炎辉 王娅玲 喻婷 樊毛迪 王航 高清清[1] 高崧[1] 刘秀梵[1] Xiang Qu;Zichun Yang;Yanhu Xu;Yaling Wang;Ting Yu;Maodi Fan;Hang Wang;Qingqing Gao;Song Gao;Xiufan Liu(Key Laboratory of Avian Bioproducts Development,Ministry of Agriculture,Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses,College of Veterinary Medicine,Yangzhou University,Yangzhou 225009,Jiangsu Province,China)

机构地区：[1]江苏省动物重要疫病与人兽共患病防控协同创新中心,农业部禽用生物制剂创制重点实验室,扬州大学兽医学院,江苏扬州225009

出　　处：《微生物学报》2020年第7期1496-1511,共16页Acta Microbiologica Sinica

基　　金：国家重点研发计划(2017YFD0500705,2017YFD0500203);国家自然科学基金(31972711,31672553,31602059);扬州大学大学生创新创业训练计划;江苏高校优势学科建设工程资助项目(PAPD)。

摘　　要：【目的】为探究脂多糖对O1、O78血清型禽致病性大肠杆菌(Avian pathogenic Escherichia coli,APEC)致病作用的影响。【方法】选取负责脂质A生物合成相关基因lpx L和lpx M,利用λ噬菌体的Red同源重组系统分别构建APECE516(O1血清型)和APECE522(O78血清型)缺失株E516Δlpx L、E516Δlpx M、E516Δlpx LΔlpx M、E522Δlpx L、E522Δlpx M和E522Δlpx LΔlpx M,并通过体内外试验对其生物学特性及致病性进行研究。【结果】各菌株生长速度基本一致。E516Δlpx L、E516Δlpx LΔlpx M、E522Δlpx M和E522Δlpx LΔlpx M的抗血清补体杀菌能力和抗鸡巨噬细胞HD-11吞噬能力较野生株显著下降,而缺失株E516Δlpx M、E522Δlpx L与野生株相比无明显差异;半数致死剂量测定结果显示,除E516Δlpx M、E522Δlpx L外,各缺失株毒力降低1000倍左右;SPF鸡体内动态分布试验结果显示,各缺失株在鸡体内定殖能力较野生株显著下降,但回补株的毒力未能恢复至野生株水平。【结论】lpx L和lpx M基因与O1血清型APECE516株和O78血清型APECE522株的毒力有关,但是lpx L和lpx M基因对E516和E522菌株毒力的影响存在差异。[Objective]To explore the role of lipopolysaccharide in Avian pathogenic Escherichia coli(APEC).[Methods]By usingλ-phage Red recombination system,we generated the lipid A biosynthesis associated genes lpx L and lpx M mutants E516Δlpx L,E516Δlpx M,E516Δlpx LΔlpx M,E522Δlpx L,E522Δlpx M and E522Δlpx LΔlpx M.We conducted a series of in vivo and in vitro assays to investigate their biological characteristics and pathogenicity.[Results]The growth rate of the strains was basically the same.The ability of resistance to serum and killing by chicken macrophages were significantly impaired,E516Δlpx L,E516Δlpx LΔlpx M,E522Δlpx M and E522Δlpx LΔlpx M were significantly attenuated than those of the wild-type strains,and E516Δlpx M and E522Δlpx L had no obvious difference in relation to their parent strains.LD50 results show that the pathogenicity of mutants was significantly attenuated than those of the wild-type strains.The colonization and survival model demonstrated that the loads of mutants were significantly decreased compared with those of the wild-type strains in all bloods and organs tested in chickens.The ability of mutants to enter and survive in chicken macrophage HD-11 is significantly reduced compared with those of the parent strains.[Conclusion]These results indicated that lpx L and lpx M genes are critical to the pathogenicity of APEC E516 and E522,lpx L had a more significant effect on virulence of APEC E516,and lpx M gene on virulence of APEC E522.

关 键 词：禽致病性大肠杆菌 类脂A 缺失株 致病力 

分 类 号：S852.61[农业科学—基础兽医学]