Wooley R E, Nolan L K, Brown J, Gibbs P S, Bounous D I
Department of Medical Microbiology, College of Veterinary Medicine, University of Georgia, Athens 30602.
Avian Dis. 1994 Jan-Mar;38(1):127-34.
An avirulent wild-type avian Escherichia coli strain (Av) was electrotransformed with plasmids coding for complement resistance (pKT107) and Colicin V (ColV) production (pHK11) in order to study the effects of complement resistance and ColV production on virulence. Transformants were also compared with the wild type for embryo lethality, uptake by macrophages, motility, growth rate, plasmid content, and hemolysis. Growth rates and complement resistance patterns of strain Av and transformant Av+pHK11 were similar, but Av+pHK11 caused a significantly greater number of deaths in embryos and acquired motility. Transformant Av+pKT107 had a lower rate of phagocytosis, a slower growth rate, and a greater sensitivity to complement, and it changed from being non-hemolytic to expressing alpha-hemolytic action. The 35-kb plasmid present in the wild type was not present in the transformants. Although some of the results demonstrate the difficulties encountered in using wild-type organisms as recipients in virulence studies, the results with Av+pHK11 indicate that ColV production plus the acquisition of motility contributes to the virulence of avian E. coli.
为了研究补体抗性和产Colicin V（ColV）对致病性的影响，用编码补体抗性（pKT107）和产Colicin V（pHK11）的质粒对无毒野生型禽源大肠杆菌菌株（Av）进行电转化。还将转化子与野生型在胚胎致死率、被巨噬细胞摄取情况、运动性、生长速率、质粒含量和溶血方面进行了比较。菌株Av和转化子Av+pHK11的生长速率和补体抗性模式相似，但Av+pHK11在胚胎中导致的死亡数量显著更多，并且获得了运动性。转化子Av+pKT107的吞噬率较低、生长速率较慢且对补体更敏感，并且它从非溶血转变为表达α-溶血作用。野生型中存在的35-kb质粒在转化子中不存在。尽管一些结果表明在毒力研究中使用野生型生物体作为受体存在困难，但Av+pHK11的结果表明产ColV加上获得运动性有助于禽源大肠杆菌的毒力。
