罗非鱼海豚链球菌的分离鉴定及药敏试验

为明确广东佛山某罗非鱼鱼场暴发疑似链球菌病的病原情况，应用脑心浸液培养基、胰蛋白大豆琼脂培养基对患病罗非鱼的肝、胆组织进行细菌分离，对获得的革兰氏阳性链球菌应用16S rDNA 引物进行基因序列鉴定，并对被确定的链球菌进行基因进化分析，同时进行阿奇霉素、链霉素、阿米卡星等10 种抗生素的药敏试验。结果表明，分离获得革兰氏阳性链球菌1 株，经16S rDNA 基因扩增鉴定为海豚链球菌；基因进化分析显示，该菌与海豚链球菌和禽的副乳链球菌亲缘关系最近；药敏试验结果显示，该菌对阿奇霉素和头孢噻肟中度敏感，对其他抗生素不敏感。

Isolation, identification and drug sensitivitytest of Tilapia Streptococcus iniae

To explore the pathogeny of suspected Tilapia Streptococcus broken out in a fish farm in Foshan,Guangdong province, bacteria in the liver and gallbladder tissue of diseased Tilapia was isolated with rainheart infusionmedium and Tryptic soy agar medium. The Gram positive Streptococcus was acquired and identified by 16S rDNA primergene sequence, then the gene evolution was analyzed and drug sensitive test was examined with 10 kinds of antibioticincluding azithromycin, streptomycin, amikacin, etc. The results showed that the isolated strain was identified as S. iniae by16S rDNA gene amplification. Gene evolution results showed that the identified Tilapia S. iniae was the most close generelationship with the reported Streptococcus and poultry vice milk Streptococcus. The drug sensitivity test result showedthat the strain was moderately sensitive to azithromycin and cefotaxime, and not sensitive to other antibiotics.