中华鳖(Pelodiscus sinensis)迟缓爱德华氏菌(Edwardsiella tarda)的分离鉴定与药物敏感性分析

Identification of Edwardsiella tarda from diseased Chinese soft-shelled turtle(Pelodiscus sinensis) and analysis on antimicrobial resistance

目前,细菌性疾病是中华鳖养殖中的常见疾病。实验采用常规方法从呈白底板症状的中华鳖(Pelodiscus sinensis)肝脏、脾脏、肾脏、胃积液等中分离纯化病原菌,经形态观察、生理生化鉴定和16S r RNA序列分析确定其种属,通过回归感染实验判断分离菌株致病性,并以纸片扩散法测定其药物敏感性。结果显示:自病鳖中分离可得到一种优势菌落,其表面湿润光滑、微隆起、半透明,呈灰黄色;基于VITEK 2的64个生化反应的分析提示,分离菌理化特性与迟缓爱德华氏菌(Edwardsiella tarda)基本一致;16S rRNA序列分析显示,其与迟缓爱德华氏菌同源性达98%以上。腹腔注射回归感染实验引起稚鳖死亡,且细菌分离能再次得到相同分离株,表明分离到的迟缓爱德华氏菌具有致病性。药敏试验表明该菌对庆大霉素、阿米卡星、新霉素、头孢哌酮、氨曲南等5种抗生素较为敏感。本研究可为中华鳖病害的正确诊断和科学防治提供参考。

The disease affected by bacteria is regular in culture of Pelodiscus Sinensis. The pathogenic bacteria were isolated from liver,kidney,spleen and gastric fluid of the diseased Pelodiscus sinensis with white abdominal shell. The species of the isolated strain was identified according to the morphological observation,physiological and biochemical characteristics identification and 16 S rRNA sequences analysis. Then,an artificial infection experiment was carried out to identify its pathogenicity. Kirby-Bauer method was used for antibiotic susceptibility test. The results showed that the bacterial strain isolated,its surface being evidenced by moist,smooth and slightly raised,translucent and grayish-yellow color,was finally identified as Edwardsiella tarda（ E. tarda） according to 64 biochemical reaction of VITEK 2 and more than 98% homologous 16 S rRNA gene sequences. In artificial infection test by injection,the isolate led to the death of juvenile turtles,and the bacterium was recovered from these artificially infected animals. The antibiotic susceptibility test revealed that the E. tarda was sensitive to gentamicin,amikacin,neomycin,cefoperazone and aztreonam. The study will provide references for correct diagnosis and scientific control of the disease in Pelodiscus sinensis.