Wray C, Piercy D W, Carroll P J, Cooley W A
Central Veterinary Laboratory, Addlestone, Surrey.
Res Vet Sci. 1993 May;54(3):290-8. doi: 10.1016/0034-5288(93)90125-y.
To examine and compare the pathogenicity of cytotoxic necrotising factor (CNF)-producing Escherichia coli, two litters of piglets were infected orally with 10(10) E coli O88 or 10(10) E coli O32 strains. Of the six piglets infected with E coli O88, two died within 24 hours and three developed blood-stained diarrhoea. The other piglets were killed one, five, six and eight days after infection, when bacterial cultures indicated an overwhelming bacteraemic infection with E coli O88 in the early stages followed by clearance through the large intestine. The pathological changes consisted of an early enteritis, progressing to enterocolitis and a bacteraemic spread to the lungs. The histopathological changes were characteristic of toxaemic effects in brain, heart, liver and kidney, and characterised by congestion, oedema and exudation. Infection with E coli O32 produced a milder but similar enterocolitis, also with bacterial colonisation in the lungs. The histopathological findings again reflected a toxaemia. The enteritis was more persistent after E coli O32 infection and the strain persisted in large numbers in the intestine. No evidence of bacterial adherence to the intestinal mucosa was found with either strain. Enteroinvasion was only evident in one E coli O88-infected piglet, but the consistent occurrence of interstitial pneumonia showed the predilection of these organisms for the lung. The results confirm the toxigenic properties of CNF+ E coli and suggest an important role for this organism in enteric infection of young pigs.
为检测和比较产细胞毒素坏死因子（CNF）的大肠杆菌的致病性，用10¹⁰个大肠杆菌O88菌株或10¹⁰个大肠杆菌O32菌株经口感染两窝仔猪。在感染大肠杆菌O88的6头仔猪中，2头在24小时内死亡，3头出现血便性腹泻。其他仔猪在感染后1天、5天、6天和8天处死，细菌培养显示早期有大肠杆菌O88引起的严重菌血症感染，随后通过大肠清除。病理变化包括早期肠炎，进展为小肠结肠炎，细菌血症扩散至肺部。组织病理学变化表现为脑、心、肝和肾的毒血症效应，特征为充血、水肿和渗出。感染大肠杆菌O32产生较轻但类似的小肠结肠炎，肺部也有细菌定植。组织病理学结果再次反映了毒血症。大肠杆菌O32感染后肠炎更持久，该菌株在肠道中大量持续存在。两种菌株均未发现细菌黏附于肠黏膜的证据。肠侵袭仅在1头感染大肠杆菌O88的仔猪中明显，但间质性肺炎的持续发生表明这些细菌对肺部有偏好。结果证实了产CNF大肠杆菌的产毒特性，并表明该菌在仔猪肠道感染中起重要作用。
