1株克氏原螯虾摩氏摩根菌的分离鉴定及联合药敏试验

从患病克氏原螯虾肝胰腺内分离到1株病原菌,通过对其生理生化特征鉴定、16S rRNA序列分析和进化树构建对分离株进行了鉴定;测定了分离株对20种抗菌药物的敏感性及抗菌药物与天然化合物联用后的协同抑菌作用。结果发现,该菌株的生理生化特征与摩氏摩根菌基本一致,进一步通过测序和进化树分析发现该菌株与摩氏摩根菌的基因相似度达到99%以上,因此该菌株鉴定为摩氏摩根菌。药敏试验发现该菌株对恩诺沙星、氟苯尼考和新霉素等7种药物高度敏感,对卡那霉素中等敏感,对多西环素、链霉素和四环素等12种药物耐药。此外,联合抑菌试验发现多西环素与二氢辣椒碱联用后具有协同抑菌作用。以上研究表明,本次从克氏原螯虾肝胰腺中分离的细菌为耐药性摩氏摩根菌,可选用氟苯尼考、恩诺沙星、新霉素或二氢辣椒碱和多西环素的复方制剂进行治疗。

dentification and synergistic susceptibility test of pathogenic Morganella morganii isolated from diseased Procambarus clarkii

A pathogenic bacterium was obtained from the hepatopancreas of diseased Procambarus clarkii.The isolated strain was determined by physiological and biochemical analysis,16S rRNA sequencing and phylogenetic analysis.Then the sensitivity of the strain to 20 kinds of antibiotics and synergistic effects of antibiotics combined with natural compounds were determined by the agar diffusion method and checkerboard assay.The results showed that physiological and biochemical characters of the isolate were similar to that of Morganella morganii,and 16S rRNA sequence determination and phylogenetic analysis showed that the isolate sequence shared over 99% similarity to that of M. morganii.Taken together,the strain was identified as an M. morganii strain.The susceptibility study showed that the strain was sensitive to enrofloxacin,florfenicol,neomycin and other 4 kinds of antibiotics,and moderate sensitive to kanamycin,resistant to doxycycline,streptomycin,tetracycline and other 9 kinds of antibiotics.Moreover,the synergistic susceptibility showed that doxycycline combined with dihydrocapsaicin had synergistic effect.Taken together,the results demonstrated that the strain isolated from the hepatopancreas of diseased P. clarkii is a resistant M. organii.Florfenicol,enrofloxacin,neomycin and doxycycline combined with dihydrocapsaicin can be chosen as candidates for treatment of M. morgani infections.