Isolation,Identification And Pathogenicity Study Of Mycoplasma Bovis

In this study,60 samples of suspected mycoplasma bovis disease collected from Hohhot area were inoculated into PPLO medium for isolation and culture,and morphological,Apodemsa staining,biochemical tests,molecular biology,drug susceptibility tests and pathogenicity tests of this animal were performed.The results showed that three M.bovis strains were successfully isolated and named HS2019,HSS2019,and HSZ2019,respectively.The results showed that all three strains of Mycoplasma bovis had fried egg-like appearance,Apodemsa staining was red punctate particles,16S rRNA and specific gene Uvrc were obtained as expected,and the homology between the three strains of Mycoplasma themselves ranged from 99.1% to 99.4%,and the homology with the model strain PG45 ranged from 98.9% to 99.2%.The growth curve of the three isolated M.bovis strains was determined,and the results were recorded to draw a curve,and the results showed that the highest bacterial amount of the three M.bovis strains could reach 1 × 10~9 CFU/mL.The results of drug sensitivity test showed that the three strains of mycoplasma were sensitive to five drugs: enrofloxacin,flufenicol,spectinomycin,tetracycline,and epinomycin,moderately sensitive to four drugs: kanamycin,amikacin,ciprofloxacin,and lincomycin,and resistant to four drugs: streptomycin,metronidazole,ceftriaxone,and ampicillin.The results of pathogenicity test showed that all three strains of Mycoplasma bovis showed clinical symptoms such as elevated body temperature,cough and dyspnea after returning to the cattle,and pathological changes of lung injury and adhesion between lung and thoracic cavity were observed after anatomy.HS2019 strain had more significant symptoms and lesions than the other two strains,with higher bacterial load.HS2019 strain had pathogenicity.To lay the foundation for further research on Mycoplasma bovis and vaccine research and development.