Contribution of the SitABCD, MntH, and FeoB metal transporters to the virulence of avian pathogenic Escherichia coli O78 strain χ7122
Contribution of the SitABCD, MntH, and FeoB metal transporters to the virulence of avian pathogenic Escherichia coli O78 strain χ7122
复制标题
DOI：
10.1128/iai.00789-07
复制
发表时间：
2008-02-01
影响因子：
3.1
通讯作者：
Dozois, Charles M.
中科院分区：
文献类型：
--
作者：
Sabri, Mourad;Caza, Missa;Dozois, Charles M.
采用等基因突变体在鸡感染模型上研究了SitABCD、MntH和FeoB金属转运体在禽致病性大肠杆菌（APEC） O78 chi 7122毒力中的作用。在单株感染模型中，与chi 7122相比，Delta sit菌株在肺、肝脏和脾脏的定植减少。补充三角洲病毒株恢复了毒力。在共同感染模型中，与APEC毒株相比，Delta sit毒株在肺部、肝脏和脾脏的定植量分别平均减少了50倍、126倍和25倍。Delta mntH Delta sit菌株进一步减弱，在血液中的持久性降低，肺、肝和脾的定植分别平均减少1400倍、954倍和83倍。在合并感染中，δ feoB δ sit菌株在血液中的持久性降低，但在肝脏中的定植增加。在两种感染模型中，Delta mntH、Delta feoB和Delta feoB的毒力与野生型相同。还测试了菌株对氧化应激产生剂的敏感性。其中Delta mntH δ sit菌株对过氧化氢、白蜡甙和百草枯的敏感性显著高于其他菌株。与共生分离株和致泻性大肠杆菌相比，该序列与APEC和人类肠外致病性大肠杆菌高度相关。比较基因组分析还表明，sit序列在共轭质粒上携带或与噬菌体元件相关，并且可能通过致病性大肠杆菌和志贺氏菌菌株之间的不同遗传事件获得。总体而言，结果表明SitABCD有助于毒力，并与MntH一起增强对氧化应激的抵抗力。
The roles of SitABCD, MntH, and FeoB metal transporters in the virulence of avian pathogenic Escherichia coli (APEC) O78 strain chi 7122 were assessed using isogenic mutants in chicken infection models. In a single-strain infection model, compared to chi 7122, the Delta sit strain demonstrated reduced colonization of the lungs, liver, and spleen. Complementation of the Delta sit strain restored virulence. In a coinfection model, compared to the virulent APEC strain, the Delta sit strain demonstrated mean 50-fold, 126-fold, and 25-fold decreases in colonization of the lungs, liver, and spleen, respectively. A Delta mntH Delta sit strain was further attenuated, demonstrating reduced persistence in blood and mean 1,400-fold, 954-fold, and 83-fold reduced colonization in the lungs, liver, and spleen, respectively. In coinfections, the Delta feoB Delta sit strain demonstrated reduced persistence in blood but increased colonization of the liver. The Delta mntH, Delta feoB, and Delta feoB Delta mntH strains were as virulent as the wild type in either of the infection models. Strains were also tested for sensitivity to oxidative stress -generating agents. The Delta mntH Delta sit strain was the most sensitive strain and was significantly more sensitive than the other strains to hydrogen peroxide, plumbagin, and paraquat. sit sequences were highly associated with APEC and human extraintestinal pathogenic E. coli compared to commensal isolates and diarrheagenic E. coli. Comparative genomic analyses also demonstrated that sit sequences are carried on conjugative plasmids or associated with phage elements and were likely acquired by distinct genetic events among pathogenic E. coli and Shigella sp. strains. Overall, the results demonstrate that SitABCD contributes to virulence and, together with MntH, to increased resistance to oxidative stress.