一株中华鳖源嗜水气单胞菌的分离鉴定及毒力基因分析

为了确定安徽某中华鳖养殖场导致中华鳖发病的病原,为今后生产中有效防控该疾病提供参考.本研究无菌条件下从患病中华鳖体内分离病原,通过形态学、生理生化特征和16SrDNA序列分析对病原菌进行鉴定;利用回归感染试验对病原菌致病性进行确定,采用琼脂扩散法进行药敏试验,并对病原的毒力基因进行分析.结果从患病中华鳖体内分离纯化得到...

Isolation,Identification and Virulence Gene Analysis of an Aeromonas hydrophila from Diseased Pelodiscus sinensis

The study aims to determine the pathogen causing disease in a Chinese soft-shelled turtle farm in Anhui Province, and provide reference for effective prevention and control of the disease in future production. The pathogenic bacteria were isolated from the moribund turtle with typical symptoms under aseptic condition, and then were identified by the morphological examination, biochemical analysis, and sequence analysis of bacterial 16S rDNA. The drug susceptibility test was conducted by Kirby-Bauer agar diffusion method, and the virulence genes of the pathogen were analyzed. The results showed that the pathogen was identified as Aeromonas hydrophila, called AM-1. Artificial infection showed that the typical symptoms of the disease could be replicated as the ones naturally occurred and this bacterium was of high pathogenicity to Chinese soft-shelled turtle. The drug resistance tests showed that the isolated pathogen was highly sensitive to enrofloxacin and levofloxacin, while extremely resistant to cotrimoxazole, ampicillin and tetracycline. The amplification results of 6 virulence genes showed that the isolated pathogen carried 5 virulence genes including aerolysin, heat-labile enterotoxin, heat-stable enterotoxin, hemolysin and elastase. This study indicates that Aeromonas hydrophila AM-1 is the pathogenic bacteria which could cause the deadly disease outbreak of the Chinese turtle. Enrofloxacin and levofloxacin can be used for treatment.