1株羊源多杀性巴氏杆菌的分离鉴定及病原特性研究OACSTPCD

[Objective]This study was aimed to identify the pathogenic bacteria that causing the disease and death of breeding sheep in a sheep farm in Qiqihar city,and to explore its etiological characteristics,so as to provide scientific basis for effective prevention and control of the disease.[Method]The lungs from dead sheep were aseptically taken,and laboratory diagnosis was conducted based on clinical symptoms.Pathogenic bacteria were isolated and cultured.Morphological observation,biochemical test,16S rRNA PCR amplification and sequencing,kmt Ⅰgene identification,capsule serotyping,virulence gene detection,drug susceptibility test,drug resistance gene detection and mouse pathogenicity test were used to identify and analyze the pathogenic characteristics of the isolated bacteria.[Result]The pathogenic strain was Pasteurella multocida.The isolated bacteria showed round raised colonies with smooth,grayish white surface on the blood plate,and Gram staining showed that the Gram-negative brevibacterium was clustered into lines or scattered in single.Biochemical test results showed that the strain could ferment maltose,arabinose,sucrose,xylose,glucose,fructose,trehalose,mannitol,urease,sorbitol and and ONPG,and arginine acid hydrolysis and indigo test were positive.Serotyping of the capsule showed that the isolate was Pasteurella multocida capsular serotype D.The drug sensitivity test showed that the isolates were resistant to enrofloxacin,bacitracin and lomefloxacin,intermediary to 4 drugs such as neomycin,and sensitive to 16 drugs such as ampicillin.The isolates carried 14 virulence genes and 6 resistance genes.All mice died after infection with the isolated bacteria.[Conclusion]One Pasteurella multocida serotype D strain was successfully isolated,carrying a variety of virulence genes and drug resistance genes,and was pathogenic to mice.This study provided data for exploring the biological information and etiological characteristics of the sheep origin Pasteurella multocida.