Davies Robert L, MacCorquodale Roslyn, Baillie Susan, Caffrey Bridget
Division of Infection and Immunity, Institute of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, UK.
J Med Microbiol. 2003 Jan;52(Pt 1):59-67. doi: 10.1099/jmm.0.05019-0.
One hundred and fifty-eight porcine strains of Pasteurella multocida, recovered primarily from cases of pneumonic pasteurellosis or progressive atrophic rhinitis (PAR) in England and Wales, were characterized by determination of their capsular types, presence or absence of the toxA gene and molecular mass heterogeneity of the heat-modifiable (OmpA) and porin (OmpH) proteins. Eighteen groups (clones) of strains were identified on the basis of specific combinations of capsular type, toxA status and outer-membrane protein (OMP)-type. The data provided evidence that different subpopulations of P. multocida are responsible for pneumonia and PAR in pigs. The majority (88 %) of cases of pneumonia were associated exclusively with non-toxigenic capsular type A strains of OMP-types 1.1, 2.1, 3.1 and 5.1 and capsular type D isolates of OMP-type 6.1. These strains were recovered from widespread geographical locations within England and Wales over a 12-year period and represented mostly single sporadic cases. The association of a small number of P. multocida variants with the majority of cases of porcine pneumonia suggests that these strains are not opportunistic pathogens of low virulence but represent primary pathogens with a relatively high degree of virulence. In contrast, the majority (76 %) of cases of PAR were associated with toxA-containing capsular type D strains of OMP-type 4.1 and capsular type A and D strains of OMP-type 6.1. Toxigenic capsular type A strains associated with PAR and non-toxigenic capsular type A strains associated with pneumonia represent distinct subpopulations of P. multocida that can be differentiated by their OMP-types. The association of capsular types A and D with strains of the same OMP-types, and the absence and presence of the toxA gene in strains of the same OMP-types, suggest that horizontal transfer of capsular biosynthesis and toxA genes has occurred between strains representing certain subpopulations of P. multocida.
158株多杀性巴氏杆菌猪源菌株主要从英格兰和威尔士的猪肺疫或进行性萎缩性鼻炎（PAR）病例中分离得到，通过测定其荚膜类型、是否存在toxA基因以及热可变蛋白（OmpA）和孔蛋白（OmpH）的分子量异质性进行特征分析。根据荚膜类型、toxA状态和外膜蛋白（OMP）类型的特定组合，鉴定出18个菌株组（克隆）。这些数据表明，多杀性巴氏杆菌的不同亚群导致猪的肺炎和PAR。大多数（88%）肺炎病例仅与OMP类型为1.1、2.1、3.1和5.1的无毒荚膜A型菌株以及OMP类型为6.1的荚膜D型分离株有关。这些菌株在12年期间从英格兰和威尔士的广泛地理位置分离得到，大多代表单个散发病例。少数多杀性巴氏杆菌变体与大多数猪肺炎病例的关联表明，这些菌株不是低毒力的机会致病菌，而是具有相对高毒力的主要致病菌。相比之下，大多数（76%）PAR病例与OMP类型为4.1的含toxA荚膜D型菌株以及OMP类型为6.1的荚膜A和D型菌株有关。与PAR相关的产毒荚膜A型菌株和与肺炎相关的无毒荚膜A型菌株代表了多杀性巴氏杆菌的不同亚群，可通过其OMP类型进行区分。荚膜A和D型与相同OMP类型的菌株相关联，以及相同OMP类型的菌株中toxA基因的缺失和存在，表明在代表多杀性巴氏杆菌某些亚群的菌株之间发生了荚膜生物合成和toxA基因的水平转移。
