Isolation,Identification And Establishhment Of PCR Method For Diagnosing Actinobacillus Pleuropneumoniae

Tree Actinobacillus pleuropneumonia isolates were obtained from the lung tissues and thoracic cavity effusions of infected pigs come from a pig farm in ChongQing. All tests indicated these isolates were Gram-negative ploymorphic bacteria, mainly rod bacteria and coccobaciIlus.They were unable to grow on both general nutritient agar plate and Macconkey nutritient agar plate .But they could form β-haemolytic small colonies on cony blood agar plate, transparent colonies of about 1-2mm in diameter on cony blood chocolate agar plate, lacte colonies on both TSB agar and general nutrient agar plate supplemented with NAD. They were all nicotinamidase adenine dinucleotide (NAD or V-factor)-dependent .Biochemical tests indicated that these isolates were urease positive, while MR-,VP- and indol-test negative. Typical symptoms of pleuropneumonia could be observed on pig challenged with these isolates.Double diffusion in two dimmention assay (DDTA) with self-made positive sera against reference strains demonstrated that isolates MC ME and MH belonged to serotyope 3,7 and 9 respectively.In this study, using self-designed primer pairs according to the reported sequences of dsbE gene, poly chain reaction(PCR) method with good specificity ,repeatability and sensibility to detect APP was successfully constructed. The minimal concentration of APP which could be detected by this method was 71CFU/mL...