Isolation And Identification Of Beef Cattle Common Respiratory Pathogenic Bacteria In Hebei Province And Research On Multiplex PCR Detection Method

In recent years,the mortality rate of cattle caused by respiratory diseases had gradually increased,caused huge economic losses to the beef cattle breeding industry.The causes of respiratory diseases and serious consequences come from a variety of pathogens,of which bacterial pathogens played an important role.At present,there were problems in the pathogens of respiratory diseases of beef cattle in Hebei Province,the accuracy of related detection techniques was low,and the cost was high.Based on this study,the common respiratory pathogens of beef cattle in Hebei Province were isolated and identified,and a multiplex PCR rapid detection method of simultaneously detecting three common pathogens were established to provide a basis for rapid diagnosis and prevention of respiratory diseases in beef cattle.Based on the current status of beef cattle breeding in various regions of Hebei Province,samples were collected in 11 cities including Qinhuangdao,Chengde,Shijiazhuang,Tangshan,Handan,Cangzhou,Baoding,Xingtai,Langfang,Zhangjiakou and Hengshui.The samples were collected beef cattle suffered from respiratory diseases.The main research contents were as follows:1.Bacterial isolation and identification of nasal swab samples.The results showed that a total of 347 strains of 15 dominant strains were identified,among which the rates of top three pathogens were 18.4% of Pasteurella multocida,16.7% of Mannheimia haemolytica,and 16.1% of Klebsiella pneumoniae,respectively.2.Determined the pathogenicity of the strain by conducting pathogenicity studies on the isolated strain.The results showed that Pasteurella multocida,hemolytic bacterium,and Klebsiella pneumoniae were highly pathogenic to mice.3.To establish a multiplex PCR method for simultaneous detection of Pasteurella multocida,Mannheimia haemolytica and Klebsiella pneumoniae from a nasal swab of a beef cattle suffered from respiratory diseases,and successfully applied to the detection of clinical samples.Conclusion: In Hebei Province,the common pathogens causing respiratorydiseases in beef cattle were Pasteurella multocida,Mannheimia haemolytica,and Klebsiella pneumoniae,respectively.The multiplex PCR assay method established in this study had stronger specificity and could quickly detect common pathogens in the respiratory diseases of beef cattle.