猪源多杀性巴氏杆菌分离鉴定及药敏试验

Isolation,identification and drug sensitivity analysis of porcine Pasteurella multocida

试验从四川地区某猪场病死猪肺脏组织中分离细菌,并对其进行形态学观察、16S rRNA序列比对、菌种特异性与荚膜血清型鉴定、毒力基因检测、药敏试验以及动物回归试验。结果显示:在病猪肺脏组织中分离得到的细菌菌落形态呈现表面光滑、细小透明的露滴状菌落;革兰染色镜检显示为革兰阴性短杆菌;16S rRNA测序结果显示,该分离菌与多杀性巴氏杆菌同源性大于99.6%;细菌种特异性KMT1基因和荚膜血清型分型鉴定,表示该分离菌为多杀性巴氏杆菌且与荚膜血清A型相符;毒力基因检测显示该分离菌携带了6种主要毒力基因(ptfA、pfhA、sodA、plpB、tonB、nanH);药敏试验结果显示,该分离菌对22种试验药物中的10种抗菌药物敏感,对7种抗菌药物耐药;动物回归试验显示该菌株能导致试验猪肺脏出血、气管有血性泡沫;且发现肝组织中存在两端钝圆小杆菌,表明该株分离菌具有较强的致病性。试验从四川地区成功分离得到1株猪源荚膜血清为A型的多杀性巴氏杆菌,对其进行了细菌生物学特性研究,同时复制了多杀性巴氏杆菌的发病模型,为防治该病提供依据。

This experiment was to Isolate bacteria from the lung organs of diseased and dead pigs in a pig farm in Sichuan,which were subjected to morphological observation,16S rRNA sequencing,identification of bacterial species specificity and capsule serotypes,virulence gene detection,drug sensitivity test,and regression testing on animals.The morphology of the bacterial colonies isolated from the lung tissues of the diseased pigs presented smooth surfaces and small transparent dewdrop-shaped colonies;Gram staining microscopy showed that they were small Gram-negative rod-shaped bacteria;16S rRNA sequencing results showed that the isolate was 99.6%homologous to Pasteurella multocida;the identification of bacterial species-specific KMT 1 gene and capsule serotyping indicated that the isolate was Pasteurella multocida and was compatible with capsule serotype A.Virulence gene detection showed that the bacteria carries six major virulence genes(ptf A,pfh A,sod A,plp B,ton B,nan H);drug sensitivity tests showed that the bacteria was sensitive to 10 antimicrobial drugs and resistant to 7 antimicrobial drugs out of 22 test drugs.The animal regression test showed that the bacteria could lead to hemorrhage in the lungs of the experimental pigs and bloody foam in the trachea;and there were bluntly rounded bacilli at both ends in the liver tissues,which suggests that the isolate has a strong pathogenicity.In this experiment,a porcine capsule serotype A Pasteurella multocida from Sichuan was successfully isolated and its bacterial biological characteristics were investigated,while the pathogenic model of Pasteurella multocida was replicated to control the disease in the future.