猪源荚膜血清F型多杀性巴氏杆菌的分离鉴定、毒力基因检测与致病性研究

Identification, virulent factors detection and pathogenesis investigation of capsule serotype F Pasteurella multocida isolated from pigs

为调查多杀性巴氏杆菌(P.multocida)在湖南猪群中的流行情况,本实验室于2015年6月~2016年3月在湖南大型屠宰场采集猪肺脏222份和猪扁桃体180份临床样品,采用血琼脂培养和PCR方法进行P.multocida的分离鉴定,得到4株F型P.multocida。对分离的4株F型P.multocida进行毒力基因检测以及小鼠的致病性研究,结果显示4株菌均含有ptf A、pfhA、fim A、sodA、sodC、ompA、ompH、oma87、plpB、exbB、exbD、tonB、hgbB、Fur、nan H、hsf-1和hsf-2毒力基因,但tadD、toxA、hgbA、nanB、pm HAS、tbpA毒力基因均为阴性;4株菌致病性试验结果显示,感染小鼠的剂量分别为4 cfu/只、5 cfu/只、11 cfu/只和17 cfu/只时可导致小鼠在60 h内全部死亡,表明这4株菌对小鼠有强致病力。病理切片显示,感染小鼠有明显的肺泡充血、脾淋巴细胞凋亡、肾小管和肾小球萎缩等病理变化。本实验首次在湖南地区分离到猪源荚膜血清F型P.multocida,并进行了较为详细的生物学特性研究,为国内P.multocida的流行情况和生猪多杀性巴氏杆菌病的防控补充了参考资料。

Four Pasteurella multocida capsule serotype F strains were isolated in this lab by using blood agar and PCR method from 222 lungs and 180 tonsils of slaughtered pigs in Hunan province during June 2015 to March 2016. 23 virulence-associated genes harboured in those 4 isolates were positive of virulence-associated genes of ptfA, pthA, timA, sodA, sodC, ompA, ompH, oma87, plpB, exbB, exbD, tonB, hgbA, Fur, nanH, hsf-1 and hsf-2 detected by PCR. Pathogenic test showed that all of the mice died after 60 hrs when inoculated intraperitoneally with the isolates at dose of 4 cfu, 5 cfu, 11 cfu and 17 cfu for each mouse, respectively, indicating these isolates were high pathogenic to mice. The alveolar hyperaemia, splenic lymphocyte apoptosis, glomerular and renal tubular atrophy of mice were revealed by histopathological examination. These results provid a basis for further study prevention and epidemiological surveillance P.multocida infection in pigs.