Taylor Jared D, Fulton Robert W, Dabo S Mady, Lehenbauer Terry W, Confer Anthony W
Oklahoma State University, Center for Veterinary Health Sciences, Department of Veterinary Pathobiology, 250 McElroy Hall, Stillwater, OK 74078-2007, USA.
J Vet Diagn Invest. 2010 May;22(3):366-75. doi: 10.1177/104063871002200304.
Bovine respiratory disease (BRD) is the most costly disease of beef cattle in North America. Because Pasteurella multocida is a commensal of the upper respiratory tract, it is generally considered an opportunistic pathogen. However, studies in swine indicated that there may be a limited number of strains associated with disease, suggesting that some are more virulent than others. Although this may also be true of isolates from cattle, appropriate typing methods must be established before this possibility can be investigated. The purpose of this study was to compare effectiveness of polymerase chain reaction (PCR) fingerprinting to more traditional approaches for typing bovine P. multocida isolates. Isolates were obtained from 41 cases of fatal BRD and subjected to random amplified polymorphic DNA PCR (RAPD-PCR), whole cell protein (WCP) profiles, outer membrane protein (OMP) profiles, and serotyping. The discrimination index was calculated for each typing method and combinations of each using Simpson's index of diversity. Correlation coefficients were calculated to assess concordance between classification results achieved through genotypic (RAPD-PCR) and phenotypic (WCP, OMP, and serotyping) approaches. All characterization methods were capable of discriminating between isolates. However, there was poor concordance between techniques. There were also few significant associations between typing results and epidemiologic data. Random amplified polymorphic DNA PCR was validated as being a repeatable and reliable means of discriminating between P. multocida isolates obtained from cattle. Isolates obtained from fatal cases of BRD in calves in a commercial feedlot demonstrated significant diversity, justifying additional investigation into whether P. multocida is a strictly opportunistic pathogen in cattle.
牛呼吸道疾病（BRD）是北美肉牛养殖中代价最高的疾病。由于多杀性巴氏杆菌是上呼吸道的共生菌，通常被认为是一种机会致病菌。然而，在猪身上的研究表明，可能只有少数菌株与疾病相关，这表明有些菌株比其他菌株更具毒性。尽管从牛身上分离出的菌株可能也存在这种情况，但在研究这种可能性之前，必须先建立合适的分型方法。本研究的目的是比较聚合酶链反应（PCR）指纹图谱与更传统的方法对牛多杀性巴氏杆菌分离株进行分型的有效性。从41例致命性BRD病例中获取分离株，并对其进行随机扩增多态性DNA PCR（RAPD-PCR）、全细胞蛋白（WCP）图谱分析、外膜蛋白（OMP）图谱分析和血清分型。使用辛普森多样性指数计算每种分型方法及其组合的鉴别指数。计算相关系数以评估通过基因型（RAPD-PCR）和表型（WCP、OMP和血清分型）方法获得的分类结果之间的一致性。所有的鉴定方法都能够区分不同的分离株。然而，不同技术之间的一致性较差。分型结果与流行病学数据之间也几乎没有显著关联。随机扩增多态性DNA PCR被验证为一种可重复且可靠的方法，用于区分从牛身上获得的多杀性巴氏杆菌分离株。从一个商业饲养场的犊牛致命性BRD病例中获得的分离株表现出显著的多样性，这使得有必要进一步研究多杀性巴氏杆菌在牛中是否只是一种严格意义上的机会致病菌。
