克氏原螯虾“五月瘟”致病菌的分离鉴定与药敏试验

Isolation,identification and drug sensitivity test of pathogenic bacteria associated with“plague of May”in Procambarus clarkii

为明确克氏原螯虾(Procambarus clarkii)“五月瘟”的主要病原,并探究其治疗方案,为克氏原螯虾“五月瘟”的防控提供技术支持。本研究通过流行病学调查、临床诊断、细菌分离纯化、人工回归感染试验、生理生化特性鉴定及16S rRNA序列扩增分析,确定引起克氏原螯虾“五月瘟”的致病菌;并根据药敏试验筛选出抗菌药物。细菌分离结果显示,患病克氏原螯虾体内分离到2株优势菌,编号分别为XX01、XX02,经回归感染试验确定2株细菌共同感染克氏原螯虾患病症状与“五月瘟”病症一样;综合其生理生化特性及分子生物学鉴定结果,确定菌株XX01为嗜水气单胞菌(Aeromonas hydrophila),菌株XX02为弗氏柠檬酸杆菌(Citrobacter freundii)。药敏试验结果显示,XX01及XX02株均对氟苯尼考等抗生素高度敏感,且选择氟苯尼考搭配黄芪多糖对克氏原螯虾“五月瘟”进行治疗,效果较好。

In order to provide technical support for the prevention and control of“plague of May”in Procambarus clarkii in the future,it is necessary to identify the main pathogen of"plague of May"and explore its treatment plan.Through epidemiological investigation,clinical diagnosis,bacterial separation and purification,artificial infection test,physiological and biochemical characteristics identification and 16S rDNA sequence amplification,the pathogenic bacteria causing“plague of May”of Procambarus clarkii were determined,and the antimicrobial drugs were screened out according to drug sensitivity test.Two dominant bacterias(numbered as XX01 and XX02)were isolated from the infected Procambarus clarkii,which were confirmed that the disease symptom co-infected by these two bacterias was same to the“plague of May”through the regression infection test.Based on their physiological and biochemical characteristics and molecular biological identification results,XX01 bacterial strain and XX02 bacterial strain were identified as Aeromonas hydrophila and Citrobacter freundii.The drug sensitivity test results showed that bacterial strains of XX01 and XX02 were highly sensitive to antibiotics such as florfenicol.Florfenicol and astragalus polysaccharide were selected to treat“plague of May”of Procambarus clarkii,which presented a good effect.