摘要
从南京市某集贸市场所售6种淡水鱼体内分离细菌,根据细菌染色、培养特性及16SrRNA基因扩增等特点进行嗜水气单胞菌的鉴定,对鉴定阳性的菌株测定其溶血、溶蛋白特性,采用PCR技术调查毒力因子的基因分布情况,以斑马鱼作为实验动物研究了不同毒力基因型代表菌株的致病性。试验共分离得到39株嗜水气单胞菌,检出率为65.0%(39/60);检测气溶素(aer)、细胞毒性肠毒素(act)、细胞兴奋性肠毒素(alt)、丝氨酸蛋白酶(ahp)和温敏胞外蛋白酶(eprCAI)等5种胞外毒力因子的基因分布情况表明,以携带3种毒力基因的菌株比例最高。随机选取3个代表菌株进行斑马鱼的致病性试验,结果发现携带全部毒力因子的E7菌株,具有很强的溶血与溶蛋白特性,对斑马鱼的LD50为3.20×106 CFU/mL,显示出较强的致病性。表明临床健康鱼体内嗜水气单胞菌的检出率很高,且携带的毒力因子类型多样,具有潜在的致病性。
Aeromonas hydrophila was isolated and identified in the freshwater fish from a market in Nanjing on the basis of bacterial staining,culture characteristics and 16 S rRNA gene amplification.For the identified strains,the hemolytic and proteolytic activities of extracellular products were tested and analyzed with respect to the prevalence of the aerolysin（aerA）,cytotoxic enterotoxin（act）,cytotonic enterotoxin（alt） and serine protease（ahp） and thermo-sensitive extracellular proteinase（eprCAI） genes by PCR assay.Three representative strains belonging to the three genetic profiles were randomly selected and tested for the median lethal dose（LD50） in zebra fish.In results,39 A.hydrophila strains were obtained and the isolation rate was 65.0%（39/60）.The genetic distribution of extracellular virulence factors showed that a higher frequency of the strains was examined with three virulence genes.The E7 strain carrying all virulence factors has strong hemolytic and proteolytic activities and LD50 for the zebra fish was 3.20×106 CFU/mL,showing high pathogenicity.These results showed that clinically healthy fish may contain very diverse A.hydrophila populations,suggesting that the potential health risks posed by A.hydrophila should not be underestimated.
出处
《中国兽医科学》
CAS
CSCD
北大核心
2011年第2期111-115,共5页
Chinese Veterinary Science
基金
教育部"新世纪优秀人才支持计划"项目(NCET-07-0440)
公益性行业(农业)科研专项(200803013)
南京农业大学SRT项目(0904A16)
