EXPERIMENTAL-INFECTION OF INFANT RABBITS WITH VEROTOXIN-PRODUCING ESCHERICHIA-COLI
EXPERIMENTAL-INFECTION OF INFANT RABBITS WITH VEROTOXIN-PRODUCING ESCHERICHIA-COLI
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DOI：
10.1128/iai.51.1.16-23.1986
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发表时间：
1986-01-01
影响因子：
3.1
通讯作者：
MEYERS, GL
中科院分区：
文献类型：
--
作者：
PAI, CH;KELLY, JK;MEYERS, GL
为了研究由产韦罗毒素（VT）的大肠杆菌引起的腹泻病的发病机制，我们给3日龄家兔注射活的大肠杆菌O157:H7（高VT产生者）、大肠杆菌O113:K75:H21（低VT产生者）或O157:H45 （VT阴性者），并检查临床症状、细菌定植、肠道中可检测到的游离VT的存在和组织学变化。腹泻与108种大肠杆菌O157:H7一致，但与更高剂量的大肠杆菌O113:K75:H21相比，很少观察到腹泻。在相同的实验条件下，vt阴性菌株未引起腹泻。大肠杆菌O157:H7从感染动物的结肠中检出的浓度明显高于从小肠中检出的浓度，临床症状与结肠中可检测到的游离VT存在相关。组织学改变主要见于结肠中、远端；这些变化的特征是表面上皮细胞凋亡大量增加，隐窝有丝分裂活性增加，粘蛋白耗损，固有层和上皮中中性粒细胞轻度至中度浸润。在肠道相关淋巴组织、盲肠和结肠的表面上皮上可见多个附着菌灶。上皮细胞和固有层未见细菌。这些粘膜异常和临床症状在幼兔单独灌胃VT后重现。这些结果与VT在大肠杆菌O157:H7和其他产生VT的大肠杆菌引起腹泻的发病机制中起主要作用的假设一致。
To study the pathogenesis of diarrheal disease due to verotoxin (VT)-producing Escherichia coli, 3-day-old rabbits were inoculated intragastrically with live E. coli O157:H7 (high VT producer), E. coli O113:K75:H21 (low VT producer), or O157:H45 (VT negative) and were examined for clinical symptoms, bacterial colonization, presence of detectable free VT in the intestines, and histological changes. Diarrhea developed consistently with 108 bacteria of E. coli O157:H7 but was observed only infrequently with even a higher dose of E. coli O113:K75:H21. VT-negative strains failed to cause diarrhea under the same experimental conditions. E. coli O157:H7 was recovered from the colon of infected animals in a significantly higher concentration than from the small intestine, and the clinical symptoms correlated with the presence of detectable free VT in the colon. Histological changes were seen mainly in the mid- and distal colon; these changes were characterized by a vast increase in apoptosis in the surface epithelium, increased mitotic activity in the crypts, mucin depletion, and a mild to moderate infiltration of neutrophils in the lamina propria and epithelium. Multiple foci of attached bacteria were seen on the surface epithelium of the gut-associated lymphoid tissue, cecum, and colon. Bacteria were never seen in epithelial cells or the lamina propria. These mucosal abnormalities as well as clinical symptoms were reproduced in infant rabbits by the intragastric administration of VT alone. These results are consistent with the hypothesis that VT plays a major role in the pathogenesis of diarrhea caused by E. coli O157:H7 and other VT-producing E. coli.