鳗鲡爱德华氏病的研究
STUDY ON THE EDWARDSIELLIASIS OF THE EEL
-
摘要: 本文记述了在我国新发现的鳗鲡爱德华氏病的症状和病原菌的特征.病鱼的症状表现为两大类型,以肾脏病变为主的肾脏型和以肝脏病变为主的肝脏型.从病鱼的内脏分离到7株菌,用其中的E86~205进行人工感染,100%的鳗鲡死亡,与自然发病的症状相似,从感染的鳗鲡上又重新分离到菌株E86-203.E86-203与E86-205以及其他菌株的特征也都一致.均为革兰氏阴性杆菌.菌体直,两端圆形,单个,大小为0.6—0.8×0.8—2.4微米.周鞭毛,运动,兼性厌氧,发酵葡萄糖产酸产气.氧化酶阴性,过氧化氢酶阳性,产生硫化氢.不能利用柠檬酸盐和丙二酸盐作为唯一的碳源,精氨酸脱氢酶阴性,赖氨酸脱羧酶阳性.属爱德华氏菌属的细菌.但是鸟氨酸脱羧酶阴性,能迅速利用纤维糖,不同于已报道的三个种(Edwardsiella tarda Ewing and McWhorter 1965,E. hoshinae Grirnont 1980,E. ictaluri Hawke 1981)中任何一个种,因此认为E86-205等菌株为一新种,定名为福建爱德华氏菌(Edwardsiel/ila fujianensis sp.nov.).Abstract: The present paper describes the symptoms of Edwardsielliasis and the characters of its pathogenic bacteria which are epidemic in some eel farms in Fujian Province.There are two types of symptoms of the diseased eel: the kidney type which shows mainly the pathological change in the kidney, and the liver type which shows mainly the pathological change in the liver.The strains of pathogenic bacteria isolated from the liver and kidney of diseased eels had identical characters. They belong to the genus Edwardsiella. The artificial infection was made by using E86-205 and all the infected eels died. The symptom was similar to that of natural incidence. When infection dosage was 1.7×107 active bacteria for each eel, mortality occurred after eight days. Again, the strain E86-203 was isolated from the infected dead eels and its characters were the same as those of E86-205. Both strains belonged to Gram-negative bacteria, measuring 0.6—0.8×0.8—2.4μm. They were peritrichous, motive, and facultatively anaerobic. They may ferment glucose and produce hydrogen sulfide; they are oxydase negative, peroxide hydrogenase positive, lysine decarboxylase positive, and ornithine and arginine negative. They may quickly utilize cellobiose.The above characters are different from those of Edwardsiella tarda, E. hoshinae and E. ictaluri. So, E86-205 is considered as a new species, and is named Edwardsiella fujianensis sp. nov.