关键词: 地高辛标记核酸探针, 猪传染性胸膜肺炎, 胸膜肺炎放线杆菌

Abstract: The APXⅣ gene, a recently discovered RTX determinant of Actinobacillus pleuropneumoniae, was shown to be species-specific. A pair of primers were designed for amplifying this 650 bp fragment in PCR experiments.The PCR products was labeled with digoxigenin as DNA probe for detection of Actinobacillus pleuropneumoniae.The hybridization assay results showed that the reference strains of the 12 serotypes of Actinobacillus pleuropneumoniae were positive, no cross-hybridization was detected with DNAs from other bacterial species closely related to A. pleuropneumoniae. The sensitivity result showed that as few as 10×10² of Actinobacillus pleuropneumoniae could be detected by DIG-labeled probe. The detection results for clinical sample tissues showed that Actinobacillus pleuropneumoniae could be found in tonsils ，trachea and lung .The high sensitivity and specificity of the DIG-labeled probe will make it useful in field diagnostic work and epidemic investigation.

Key words: digoxigenin-labeled nucleic acid probe, Actinobacillus pleuropneumoniae, porcine pleuropneumonia