豬F18（+）－VT腸毒性大腸桿菌本省分離株之特性

2000年間，於台灣中部兩個飼養10,000頭之一貫式養豬場，發生嚴重之離乳豬下痢及瘁死情形，雖然給予藥物治療，但是仍有20%豬隻經過數日即告死亡。經由屠體解剖結果，可觀察到肉眼病變包括眼瞼、局部頭部及鼠蹊部皮下呈水腫變性，小腸腸間膜及結腸漿膜呈透明膠狀水腫等變性現象。從小腸以及臟器檢體中可以分離到疑似溶血性之大腸桿菌，細菌學及PCR檢測法分析結果，則發現這些分離株分屬於大腸桿菌附著因子K88及F18型兩族群，K88型分離株具有忌熱性腸毒素（LT）或耐熱性腸毒素（ST）基因，而F18型則含有佛羅毒素（verotoxin, VT）基因。利用小鼠進行腹腔攻毒試驗時，發現K88-ST、K88-ST-VT或F18-VT等菌株皆可導致小鼠活動力下降、下痢，甚至死亡，其中F18-VT菌株則會造成小鼠神經性抽搐之特殊臨床症狀。在SPF乳豬攻毒試驗，口服接種F18-VT可以出現明顯的水腫病病變與神經症狀。由以上實驗證據顯示，引起仔豬水腫及下痢或瘁死之檢體中，除了K88毒素性大腸桿菌外，另一種屬於F18-VT菌型亦可被廣泛的分離，並且經由SPF乳豬之攻毒試驗證明，F18-VT菌株確實可以導致豬隻罹患水腫病。

關鍵字

水腫病； F18大腸桿菌；佛羅毒素

並列摘要

In 2000, serious diarrhea and sudden death attacked nursery piglets at two farms in central Taiwan, with the outbreak, involving ten thousands of pigs. Despite medical treatment, 20% of the piglets died within several days of the onset of disease. Necropsy conducted on dead piglets generally revealed edema in both eyes, the forehead, and the inguinal area, with the presence of mesenteric lymph nodes, and colonic serosa. Suspiciously hemolytic E. coli were isolated from the small intestines and other organs. PCR revealed two major adhesion types, namely E. coli K88 and F18. Moreover, PCR also revealed that most of the K88 isolates contained heat-stable toxin (ST) or heat-labile toxin (LT) genes and F18 isolates containing the verotoxin (VT) toxin gene. Intrapretonial inoculation testing on experimental mice revealed that both strains caused diarrhea, decreased activity, and even death. However, the F18-VT strain also caused additional distinct clinical manifestations such as neurological seizure. Edema and neurological disease were observed in SPF piglets following oral challenge with F18-VT. This investigation demonstrates that the F18-VT strain is generally isolated as well as K88 E. coli in piglets dying from edema and diarrhea. Further SPF piglet challenge studies confirm that F18-VT cause edema disease in pigs.

並列關鍵字

Edema disease ； F18 E. coli ； Verotoxin

國際替代計量

豬F18（+）－VT腸毒性大腸桿菌本省分離株之特性

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