致林麝猝死的病原豚鼠气单胞菌的分离与鉴定

Isolation and identification of Aeromonas caviae from the suddenly dead Moschus berezovskii

为了确定引起两头圈养林麝猝死的主要病原菌,确定合理的临床用药和预防方案,本研究采用血平板对死亡林麝的心、肝、脾、肺、肾等组织器官中可疑病原进行分离,通过菌落形态学观察、革兰染色镜检、16S rDNA序列测定分析、生化试验、致病性试验及药敏试验(DST)进行鉴定。通过16S rDNA基因的系统进化研究发现,从猝死林麝体内分离的细菌与豚鼠气单胞菌S5-3株的同源性高达99.9%,结合生化试验结果进行综合分析,确定致林麝猝死的致病菌为豚鼠气单胞菌。药敏试验结果显示,该菌株对氨苄西林、卡那霉素、链霉素、环丙沙星、头孢哌酮较敏感,对头孢他啶、哌拉西林、庆大霉素、复方新诺明、四环素为中敏,对红霉素、青霉素、利福平、头孢拉定、呋喃妥因存在多重耐药性;通过PCR检测分析,发现该菌株携带耐药基因bla-OXA和bla-PER;动物试验表明,给予小鼠接种3.9×10~8 CFU/0.3 m L的剂量会导致小鼠全部死亡,说明该菌株具有较强致病性。本研究结果对林麝养殖生产中临床用药具有一定的指导意义。

To define major pathogeny that led to the death of Moschus berezovskii and to find appropriate clinical treatment and prevention method,in this study, blood agar was used to separate potential bacteria from the heart,liver,spleen,lung and kidney of two dead Moschus berezovskiis and the bacteria were identified by morphological observation, gram stain and microscopic examination,16 S rDNA sequence analysis,biochemical experiment,pathogenicity test and DST.The results indicated that the homology rate of bacterium isolated from dead Moschus berezovskiis was 99.9% between Aeromonas caviae S5-3 strain.The comprehensive analysis confirmed the pathogen was A.caviae.The antimicrobial susceptibility tests indicated this bacterium was susceptible to ampicillin,kanamycin,streptomycin,ciprofloxacin and cefoperazone,and was medium susceptibility to ceftazidime,piperacillin,gentamicin and sulfamethoxazole,but had multiple resistance to erythromycin,penicillin,rifampin,cephradine and nitrofurantoin.PCR analysis confirmed that this strain had drug resistance gene of bla-OXA and bla-PER.The animal experiment demonstrated that all mice died at the dose of 3.9 ×10~8CFU/0.3 mL. Those suggested that this A.caviae strain had strong pathogenicity.This study could give some clues to the clinical pharmacy in the breeding and production of Moschus berezovskiis.