将从病死的牛、猪和鹅肝脏内分离的3株菌分别进行分离纯化、革兰染色镜检、生化试验和药敏试验,对其16S rRNA基因进行PCR扩增、测序、同源性比对,测定其毒力和耐药相关基因.结果显示,3株均为革兰阴性杆菌.16S rRNA基因序列同源性分析显示,2株分离菌与普通变形杆菌同源性高达99.9%,另外1株与奇异变形杆菌同源性高达100%.毒力基因检测表明,2株普通变形杆菌携带rpoA和fliL,奇异变形杆菌携带hpmA、hpmB、rpoA和fliL,均为编码溶血素和鞭毛的基因.药敏试验结果显示,3株变形杆菌对多种抗菌药物耐药,仅对头孢吡肟等敏感.对其耐药基因——头孢菌素酶(ampC)基因检测结果与药敏试验的结果基本一致.3株不同来源的分离菌均为变形杆菌,其致病性可能与其含有编码溶血素以及鞭毛的基因有关,对头孢菌素类耐药性可能与其携带ampC基因有关.
Three strains of suspected Proteus were isolated and identified,and then virulence-associated genes and cephalosporin resistant enzyme (ampC) gene were amplified by PCR.The results showed that the three bacterial strains isolated from the livers of cattle,pigs and geese were Gram-negative bacilli.Homology analysis showed that two strains have 99.9% of homology with Proteus vulgaris,while the other one strain has 100% homology of Proteus mirabilis.The results of virulence gene detection showed that two strains of P.vulgaris contained rpoA andfliL,while P.mirabilis contained hpmA,hpmB,rpoA andfliL,all of which are the genes encoding hemolysin and flagella.The results of susceptibility test showed that the three strains of Proteus were able to resist a variety of drugs,and only cefepime was effective.The detection results of the drug resistance gene ampC are in accordance with that of drug susceptibility data.It suggested that the pathogenicity of the three Proteus strains may be related to the genes encoding hemolysin and flagellin,and ampC gene may be involved in their resistance to cephalosporins.