Doyle D, Credille B, Lehenbauer T W, Berghaus R, Aly S S, Champagne J, Blanchard P, Crossley B, Berghaus L, Cochran S, Woolums A
Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA.
Veterinary Medicine Teaching and Research Center, School of Veterinary Medicine, University of California, Davis, Tulare, CA.
J Vet Intern Med. 2017 May;31(3):954-959. doi: 10.1111/jvim.14683. Epub 2017 Mar 14.
Four sampling techniques commonly are used for antemortem identification of pathogens from cattle with bovine respiratory disease (BRD): the nasal swab (NS), guarded nasopharyngeal swab (NPS), bronchoalveolar lavage (BAL), and transtracheal wash (TTW). Agreement among these methods has not been well characterized.
To evaluate agreement among TTW and NS, NPS, or BAL for identification of viral and bacterial pathogens in dairy calves with BRD.
One hundred dairy calves with naturally acquired BRD.
Calves were sampled by all 4 methods. Viral agents were identified by real-time RT-PCR, bacteria were identified by aerobic culture, and Mycoplasma bovis (M. bovis) isolates were speciated by PCR. Agreement among TTW and NS, NPS, or BAL was evaluated by calculating the kappa statistic and percent positive agreement. McNemar's exact test was used to compare the proportions of positive results.
Agreement among TTW and NS, TTW and NPS, and TTW and BAL, was very good for identification of P. multocida, M. haemolytica, and M. bovis. For bovine respiratory syncytial virus (BRSV), agreement with TTW was moderate for NS, good for NPS, and very good for BAL. For bovine coronavirus (BCV), agreement with TTW was moderate for NS and NPS, and good for BAL. McNemar's test was significant only for BCV, indicating that for this pathogen the proportion of positive results from NS and NPS could not be considered comparable to TTW.
This study provides guidance for veterinarians selecting diagnostic tests for antemortem identification of pathogens associated with BRD.
四种采样技术常用于对患有牛呼吸道疾病（BRD）的牛进行生前病原体鉴定：鼻拭子（NS）、保护鼻咽拭子（NPS）、支气管肺泡灌洗（BAL）和经气管冲洗（TTW）。这些方法之间的一致性尚未得到很好的描述。
评估TTW与NS、NPS或BAL在鉴定患有BRD的奶牛犊病毒和细菌病原体方面的一致性。
100头自然感染BRD的奶牛犊。
对所有犊牛采用这4种方法进行采样。通过实时逆转录聚合酶链反应（RT-PCR）鉴定病毒病原体，通过需氧培养鉴定细菌，通过PCR对牛支原体（M. bovis）分离株进行分型。通过计算kappa统计量和阳性一致率来评估TTW与NS、NPS或BAL之间的一致性。采用McNemar确切检验比较阳性结果的比例。
TTW与NS、TTW与NPS以及TTW与BAL在鉴定多杀性巴氏杆菌、溶血曼氏杆菌和牛支原体方面的一致性非常好。对于牛呼吸道合胞病毒（BRSV），与TTW的一致性NS为中等，NPS为良好，BAL为非常好。对于牛冠状病毒（BCV），与TTW的一致性NS和NPS为中等，BAL为良好。McNemar检验仅对BCV有显著意义，表明对于该病原体，NS和NPS的阳性结果比例与TTW不可比。
本研究为兽医选择用于生前鉴定与BRD相关病原体的诊断试验提供了指导。
