牙鲆迟钝爱德华氏菌吲哚阴性变异株感染症及其病原特性研究

Characterization of the indole negative variant of Edwardsiella tarda isolated from flounder

目的 分离鉴定了牙鲆 (Flounder ,ParalichthysolivaceusL .)病原迟钝爱德华氏菌吲哚阴性变异株 (E .tardain dole negative)并对其特性进行了研究。 方法 对牙鲆迟钝爱德华氏菌 (Edwardsiellatarda)感染病例进行了自然病例检验 ,病原细菌的分离与鉴定、血清型检定、致病力检验、荧光抗体检验及药物敏感性测定。结果 通过对牙鲆迟钝爱德华氏菌感染病例发病情况、临床特征、病理变化等方面的检验及细菌的分离与鉴定 ,表明所检病例为迟钝爱德华氏菌吲哚阴性变异株感染。对分离后做纯培养的 2 0株菌进行了主要生物学性状及血清型的测定 ,表明 2 0株分离菌对所测各项特征的结果一致 ,且均为同种血清型。分离代表菌株做对健康牙鲆鱼的人工感染试验表明了相应的原发病原学意义及较强的致病作用。药敏试验结果表明 ,对供试 37种抗菌药物中的头孢唑啉等 2 2种药物敏感、对青霉素G等 7种药物耐药、对氨苄青霉素等 8种药物表现了株间差异。以荧光抗体技术对纯培养物、人工感染病死鱼肝脏中细菌的检验 ,均呈现了特异荧光反应。结论 从牙鲆病例分离鉴定了迟钝爱德华氏菌吲哚阴性变异株 ,研究报告了其主要生物学特性 ,为对由此类病原菌引起的牙鲆感染症的有效检验与防治及进一步研究等奠定了基础。

The characterization of the indole negative variant of Edwardsiella tarda isolated from flounder (Paralichthys olivaceus L) are described in this paper, including isolation and identification of pathogen, serological identification, tests for pathogenicity, fluorescent antibody testing and drug sensitivity determination. From the 20 isolates examined, it was found the biological properties of all isolates were consistent and belong to the same serotype. The representative strains selected from 20 pure cultures of organisms were proved to be the causal agent for the artificial infection of flounder. Antimicrobial susceptibility tests showed that all strains were sensitive to cefazolin and other 21 chemopedetics, but they were resistant to penicillin G and other 6 drugs. There existed strain differences to the actions of ampicillin and 7 drugs. Through examination of the pure cultures and the isolates from morbid and dead fishes of experimental infection by fluorescent antibody technique, it was proved that all the examined strains demonstrated special fluorescent reaction.