鲟源致病性嗜水气单胞菌X1的分离鉴定与药敏特性研究

Isolation and Identification of Aeromonas hydrophila Strain X1 from Acipenser baerii and Its Antibiotic Sensitivity

摘要:

从患细菌性败血症的西伯利亚鲟(Acipenser baerii)的体内分离到一株致病菌株X1, 其对西伯利亚鲟的半数致死浓度(LC50)为5.62×105 CFU/mL, 具有较强毒力; 菌株X1为革兰氏阴性杆菌, 菌体大小为1.0 μm~1.2 μm×2.1 μm~2.4 μm, 周生侧鞭毛, 在兔血琼脂平板上能形成明显的β-溶血圈, 经ATB细菌鉴定仪鉴定和16S rDNA序列分析, 菌株X1为嗜水气单胞菌(Aeromonas hydrophila)(登录号：EU669667); 其系统发育分析表明, 菌株X1与嗜水气单胞菌ATCC35654(登录号：X74676.1)的亲缘关系最近, 其同源性为99％。此外, 菌株X1对先锋必、左氟沙星等2种药物高度敏感, 对妥布霉素、氟哌酸、舒普深、卡那霉素、庆大霉素、复达欣、万古霉素、新霉素、多粘菌素B、洛美沙星等10种药物中度敏感。

Abstract:

A pathogenic bacterial strain X1 was isolated from Siberian sturgeon (Acipenser baerii) suffering with bacterial septicemia. The 50% lethal concentration (LC50) of strain X1 was 5.62×105 CFU/mL, which showed that strain X1 was rather strong virulent to Acipenser baerii. Strain X1 was gram negative and 1.0 μm~1.2 μm × 2.1 μm~2.4 μm in size with peritrichous flagella, and had β-hemolytic activity on rabbit blood agar. By means of ATB expression identification and 16S rDNA sequence analysis, strain X1 was identified as Aeromonas hydrophila (locus number: EU669667), which was the closest relative to Aeromonas hydrophila strain ATCC35654 (locus number: X74676.1) with 99% homology. In addition, strain X1 was highly sensitive to cefoperazone and cravit, and intermediately sensitive to ten kinds of antibiotics including tobramycin, norfloxacin, sulperazone, kanamycin, gentamycin, fortum, vancomycin, neomycina, polymyxin B and lomefloxacin.