Tabatabai Louis B, Zimmerli Mandy K, Zehr Emilie S, Briggs R E, Tatum Fred M
National Animal Disease Center, USDA, Agricultural Research Service, Ames, IA 50010, USA.
Avian Dis. 2010 Sep;54(3):994-1001. doi: 10.1637/9070-091409-Reg.1.
Ornithobacterium rhinotracheale is a gram-negative bacterium responsible for the sporadic outbreaks of airsacculitis in poultry, accounting for millions of dollars in losses to the poultry industry annually. Although the organism was originally classified as non-beta-hemolytic, recent North American field isolates of O. rhinotracheale obtained from pneumonic lungs and air sacs indicated hemolytic activity on blood agar plates upon extended incubation for 48 hr at room temperature in air after initial incubation at 37 C for 48 hr under 7.5% CO2. This report characterizes the beta-hemolytic activity of O. rhinotracheale isolates by using in vitro kinetic hemolysis assays with sheep red blood cells, western blotting with leukotoxin-specific monoclonal antibodies, and isobaric tagging and relative and absolute quantitative (iTRAQ) analysis of O. rhinotracheale outer membrane protein digest preparations. The kinetic analyses of the hemolytic activity with red blood cells indicated that the protein is a pore former. iTRAQ analysis with membrane preparations revealed four peptides with homology to Mannheimia haemolytica leukotoxin and two peptides with homology to Actinobacillus actinoacetemcomitans leukotoxin. This is the first report that North American field isolates of O. rhinotracheale may express a hemolysin-like activity.
禽气管鸟杆菌是一种革兰氏阴性菌，可引发家禽气囊炎的散发性暴发，每年给家禽业造成数百万美元的损失。尽管该菌最初被归类为非β溶血菌，但最近从患肺炎的肺脏和气囊中分离出的北美禽气管鸟杆菌野外菌株，在37℃下于7.5%二氧化碳环境中初步培养48小时后，再于室温空气中延长培养48小时，结果显示在血琼脂平板上具有溶血活性。本报告通过使用绵羊红细胞进行体外动力学溶血试验、用白细胞毒素特异性单克隆抗体进行蛋白质印迹分析以及对禽气管鸟杆菌外膜蛋白消化制剂进行等压标记和相对与绝对定量（iTRAQ）分析，对禽气管鸟杆菌分离株的β溶血活性进行了表征。对红细胞溶血活性的动力学分析表明该蛋白是一种成孔蛋白。对膜制剂进行的iTRAQ分析揭示了四种与溶血曼氏杆菌白细胞毒素具有同源性的肽段以及两种与伴放线放线杆菌白细胞毒素具有同源性的肽段。这是关于北美禽气管鸟杆菌野外分离株可能表达溶血素样活性的首次报告。
