Isolation And Identification Of Pathogenic Bacteria In Sheep Mastitis And Immune Effect Evaluation Of Inactivated Vaccine

Mastitis is a common and harmful disease in mammals,which seriously affects the lactation function of animals and poses a threat to the health of mammals and newborn animals.As a high-quality meat variety,sheep are widely cultivated in Qinghai,Gansu,Tibet and other regions of China,but for a long time,the research on mastitis has mainly focused on dairy cows and dairy goats,while the research on sheep mastitis is relatively rare.This study is mainly aimed at sheep mastitis in Qinghai Province,in order to provide a theoretical basis for the diagnosis and prevention of sheep mastitis.In this study,clinical mastitis milk samples were collected from Qinghai sheep.The pathogenic bacteria in the milk were isolated and identified by bacterial isolation,gram staining,16 S rDNA sequence analysis and specific PCR amplification,the pathogenic bacteria were tested for drug susceptibility.An inactivated vaccine was prepared using the isolated and identified sheep mastitis pathogenic bacteria Staphylococcus aureus and Escherichia coli.The goats in the Qianyang area of Shaanxi were immunized and the antibody titer in the milk and blood of the dairy goats was determined by indirect ELISA,The number of sheep suffering subclinical mastitis was detected by rapid diagnostic reagent.The research results are as follows:1.Four major pathogens of sheep mastitis were isolated,including Staphylococcus aureus,Escherichia coli,Streptococcus,and Bacillus cereus.2.Staphylococcus aureus was sensitive to cephalosporins and macrolides,resistant to penicillins and aminoglycosides;Escherichia coli was sensitive to most aminoglycosides and tetracyclines,and resistant to penicillins medicinal.Streptococcus was sensitive to most antibacterial drugs;Bacillus cereus was sensitive to aminoglycosides and has high resistance to penicillins.3.After two immunizations,the antibody titer against Staphylococcus aureus and Escherichia coli in milk and blood was significantly increased,and within 60 days after immunization,the detection rate of subclinical mastitis decreased by 15.2%.Conclusions:1.The pathogenic bacteria of sheep mastitis were successfully isolated.2.The drug resistance of the main pathogenic bacteria of sheep mastitis was clarified.3.The inactivated vaccine against sheep mastitis development in this study can stimulate the body to produce higher levels of antibodies and has a certain therapeutic effect on subclinical mastitis.