摘要
2001年9月—12月,浙江舟山部分网箱养殖红拟石首鱼发生了陆续死鱼,发病鱼表现为眼球突出、浑浊,失去方向性,皮肤溃疡等症状。从病鱼的肾脏和肝脏中分离到菌株SO-2和SO-3,对两分离株进行了致病性试验,发现两者对红拟石首鱼、罗非鱼及小白鼠均有致病力,SO-2和SO-3对红拟石首鱼、罗非鱼及小白鼠的LD50分别为4.8×108CFU/尾和1.9×107CFU/尾2、.8×108CFU/尾和8.3×107CFU/尾及9.6×106CFU/只和4.2×106CFU/只,试验感染鱼出现眼球突出、浑浊及失去方向性等与自然发病相似症状,确定该两株菌为致病菌。两分离株为革兰氏染色阳性,呈链状球菌,β溶血,10℃生长,45℃不生长;接触酶阴性,水解七叶灵、精氨酸;VP试验、脲酶和马脲酸试验阴性,发酵葡萄糖、水杨苷、蔗糖和淀粉,不发醇阿拉伯糖、菊糖、乳糖、蜜二糖、棉子糖和山梨醇。分离株对氨卞青霉素、万古霉素和先锋Ⅴ等高度敏感,对庆大霉素、复方新诺明、林可霉素、氟哌酸等不敏感。应用16SrRNA基因进行的菌株PCR鉴定,确定该两株菌为海豚链球菌。
In recent years,red drum（ Sciaenops ocellatus）became the economic important species of marine cage-culture in Zhejiang Province. During September to October 2001, continuous mortality of cage-cultured red drum was recorded in Zhoushan, with the symptoms of skin lesions,exophthalmia and disorientation, etc. Two bacterial strains SO-2 and SO-3 were isolated from the kidney of moribund red drum. The pathogenicity of these two isolates to red drum, tilapia and mouse was tested. The LD50 of SO-2 and SO-3 to red drum were 4.8×10^8CFU/fish and 1.9×10^7 CFU/fish,to tilapia 2.8×10^8CFU/fish and 8.3×10^7CFU/ fish, to mouse 9.6×10^6CFU/mouse and 4.2×10^6CFU/mouse, respectively. The challenged fish presented the similar external signs to natural infected red drum, such as exophthalmia and disorientation. These two isolates were preliminarily identified as Streptococcus iniae with the characteristics of gram-positive cocci in chains, catalase negative and beta-hemolytic, growth under 10℃ and non-growth up 45℃ , hydrolyzation of esculin and arginine, Voges-Proskauer, urease, and hippurate tests negative, fermentation of glucose, salicin, sucrose and starch, non-fermentation of arabinose, inulin, lactose, melibiose, raffinose and sorbitol. They were highly sensitive to ampicilin,vancomycin and cefazolin, while resistant to gentamicin, compound sulfamethoxazole, lincomycin and norfloxacin. Polymerase chain reaction（PCR）of 16SrRNA gene was carried out by using the primers specific for Streptococcus iniae and a 300bp product was identified with 2% agar electrophoresis, which confirmed the identification of these two isolates as Streptococcus iniae.
出处
《水生生物学报》
CAS
CSCD
北大核心
2005年第6期678-683,共6页
Acta Hydrobiologica Sinica
基金
浙江省自然科学基金(Y3004425)资助
关键词
红拟石首鱼
海豚链球菌
致病性
鉴定
Red drum（ Sciaenops ocellatus ）
Pathogenicity
Streptococcus iniae
Identification
