异育银鲫(Carassius auratus gibelio)源醋酸钙不动杆菌表型及分子鉴定

摘要

A purely cultured strain (SY-1) isolated from blood of sick Carassius auratus gibelio,and its culture characteristics,main morphological physiological and biochemical characteristics were examined.It is found that its salinity range is 5-30,pH range is 6-8 and its growth temperature range is from 10℃ to 42℃.Detection of the activity of extracellulase shows that the isolate could just produce urease.For further confirmation on molecular level,16S rRNA gene was sequenced; and the accession number in GenBank is JX164201 in length of 1435bp.Sequences analysis on the 16S rRNA gene shows that it is very similar to other Acinetobacter,and their nucleotide homology was between 99％ and 100％.Its phylogenetic tree show that the pathogen isolated from the diseased C.auratus gibelio was identified as Acinetobacter calcoaceticus.The challenge test using SY-1 to the fish displayed that the prevalence of symptoms and spontaneous onset symptoms were the same.The antibiotic sensitivity using 39 antimicrobial agents showed that isolates were sensitive to 10 agents,including enrofloxacin,doxycycline,nalidixic acid,cotrimoxazole,and ofloxacin,etc; sensitive slightly to 14 agents,including penicillin,norfloxacin,spectinomycin,kanamycin,and tetracycline,etc; and resistant to 15 agents,including ampicillin,lincomycin,oxacillin,vancomycin,and florfenicol,etc.%采用常规的培养特征、理化特性及分子生物学的方法,对从濒死异育银鲫(Carassius auratus gibelio)血液中分离到的菌株SY-1进行了致病性、表型生物学、分子生物学及药敏试验的系统研究.结果表明,该菌株在盐度5-30、pH 6-8,温度10-42℃的LB液体培养基中均能生长,具有脲酶.该菌株16S rRNA基因序列(GenBank登录存取号:JX164201,长度1435bp)与其它不动杆菌属菌的16S rRNA基因同源性相似性在99％-100％之间,构建系统发育树确定该菌株为醋酸钙不动杆菌(Acinetobacter calcoaceticus).人工回感可导致异育银鲫死亡.药敏试验结果显示:对恩诺沙星、强力霉素、萘啶酸、复方新诺明、氧氟沙星等10种抗生素敏感；对羧苄青霉素、诺氟沙星、大观霉素、卡那霉素、四环素等14种抗生素中度敏感；对氨苄西林、苯唑西林、林可霉素、万古霉素、氟苯尼考等15种抗生素耐药.