查干湖鲢源豚鼠气单胞菌分离鉴定及生物学特性研究

为了探讨2020年初吉林省查干湖分支甩湾子出现鲢大面积死亡现象的原因,从发病鲢中分离纯化出1株具有生长优势的菌株,并对分离菌株进行细菌形态观察和生理生化试验,用16SrDNA和管家基因的序列分析进行分子水平鉴定及系统进化树分析,之后对分离株进行携带毒力基因情况、生长曲线测定、人工感染试验及药敏试验.结果显示,分离菌株为...

Isolation,Identification and Biological Characteristics of Aeromonas caviae from Silver Carp in Chagan Lake

In order to explore the reason for the large-scale death of silver carp at the beginning of 2020 in Chagan Lake branch of Jilin Province,the experiment was conducted to isolate and purify a strain with growth advantages from diseased silver carp,and then conduct morphological observation and physiological and biochemical tests on the isolated strain for the preliminary identification,and use 16S rDNA and housekeeping gene sequence analysis to carry out molecular level identification and phylogenetic tree analysis,and then carry out the virulence gene status,growth curve determination,artificial infection test and drug susceptibility test on the isolates.The results showed that the isolated strain was Gram-negative.The tests of rhamnose,dulcitol semi-solid,ONPG,mannitol,malonate,arabinose,lactose,lysine decarboxylase,amino acid decarboxylase,and gelatin were positive.Through the comprehensive physiological and biochemical tests,16S rDNA and housekeeping gene identification,it can be judged that the isolate belongs to Aeromonas caviae.The PCR results of the virulence genes of the isolated strain showed that the isolated strain carried 7 virulence genes,and their median lethal doses to zebrafish and silver carp were 2.51×102 CFU and 2×104 CFU,respectively,indicating the strain is highly pathogenic.Moreover,the results of the drug susceptibility test showed that the isolate was only highly sensitive to piperacillin,doxycycline,cefoperazone,amikacin,tetracycline,kanamycin,furazolidone,gentamicin,neomycin,norfloxacin,ofloxacin,ciprofloxacin,and chloramphenicol,indicating that the isolated strain is multi-drug resistant strain.