湖南地区猪源多杀性巴氏杆菌部分保护性抗原基因分子流行病学调查

Molecular epidemiological survey of protective antigen genes in Pasteurella multocida isolated from swine

为探索多杀性巴氏杆菌(Pm)的保护性抗原基因在A与D血清型之间分布规律及其保守性,本研究通过对湖南地区分离的92株(A型:50株;D型:42株)猪源Pm的ompA、ompH、omp87、plpE、plpP、ptfA、fhab2、vacJ和tbpA等9种保护性抗原基因进行PCR检测。结果显示:在以上9种基因中ompA、ompH、omp87以及ptfA的检出率最高,均为100%;vacJ和plpP基因的检出率分别为91%和66%。而fhab2和plpE基因仅在A型菌株中检出,检出率分别为42%和40%。选取部分菌株,对其4种检出率为100%的基因进行测序显示,omp87的同源性介于99.1%~100%;ptfA的同源性介于97.2%~100%;ompA的同源性介于91.2%~100%;ompH的同源性介于84.6%~100%。此外,经抗原表位预测,omp A和ompH基因在部分抗原表位区域存在明显差异。本研究发现omp87和ptfA两个基因存在于本研究分离的92株猪源Pm,并且相当保守,该结果为巴氏杆菌基因工程亚单位疫苗开发过程中保护性抗原的选择提供了依据。

To investigate the prevalence and profile of genes encoding protective antigens in serotype A and D of Pasteurella multocida, nine genes including ompA, ompH, omp87, pipE, plpP, ptfA, thab2, vacJ and tbpA in 92 P.multocida isolated fromclinical samples were detected by PCR. The results showed that ompA, ompH, omp87, plpP and ptfA existed in all of these isolates, 91% and 66% of them contain vacJ and plpP, respectively. However, thab2 and pipE only found in 42% and 40% of theisolates in serotype A of P.multocida. In addition, four genes in some of the isolates were sequenced for their existing in all tested isolates, which showed that nucleotide sequences of omp87, ptfA, ompA and ompH were 99.1 to 100%, 97.2 to 100%, 91.2 to100% and 84.6 to 100% identity among these isolates. It was worth to note that the ompA and ompH existed in all the isolates, but the regions predicted as epitopes encoding sequeces were variable. These results render information for protective antigens screening in the development of subunit vaccines.