Isolation And Identification Of Mycoplasma Synoviae And Its Partial Biological Characteristics

Mycoplasma synoviae (MS) may cause chicken bursitis, which is an acute or chronic infectious disease of chicken, is characterized by the damage of synovial membranes of joints and tendon sheaths, and causes joint exudative synovitis, tendovaginitis and feet swelling. The infection with this disease of chicken can lead to obvious limp, growth retardation and acetone degradation, and is associated with respiratory diseases. As same as Mycoplasma gallisepticum (MG), the MS infection has spread all over the world. In our country, the MS infection occurs, whether among commercial broilers, laying hens or breeding hens, which has led to huge economic losses to the poultry industry.This study obtains the following results by the isolation and identification of MS, the characteristics of growth, the test of artificial infection, and the determination of immune antibody level:(1) The isolation and identification of MS:it is done by collecting joint fluid and contents of swollen tarsal joint cavity of suspected MS infection chicken in different farms in Henan privince, Jangsu privince, and Guangdong privince, in aseptic condition, from January to December in2012. We have isolated10strains of Mycoplasma synoviae from the contents of swelling footpad of102chicken which legs are paralyzed, isolation rate being7.14%-14.29%, with the average isolation rate of9.8%. We identify Mycoplasma synoviae through this test combined with colony morphology, Gram staining, microscopic examination, erythrocyte adsorption, L bacterial identification, biochemical test, serology, sequence analysis of isolated strains vlhA gene, and the artificial infection test. The results of drug sensitivity test to isolated strains (HN01、JS01、JS02、GD01) show that Mycoplasma synoviae is highly sensitive to tylosin and Barry mycin, but has obvious resistance to Lin Zhuang mixture, lincomycin hydrochloride and roxithromycin id.(2) The biological characteristics of MS:the variation range of CCU in the process of strains growth is3～9CCU/ml, the growth peak of MS can be reached between36h-40h, and culture titer can up to109CCU/ml. The activity of MS synoviae maintains activity more than1month in-70℃,-20℃for7d,-4℃for2d, and25℃for only Id. Within30%sterile glycerol, MS maintains activity more than12months at-70℃,-20℃for21days. The results of Mycoplasma synoviae infection model show that the isolated strain (HN01、 JS01、JS02、GD01) can cause clinical symptoms and typical pathological changes with the inoculation of footpad of SPF chicken. And we can isolate MS from the infected chicken. We find the claw pad injection also can induce typical clinical cases of MS, but the incidence of MS of venous injection group is lower than that of footpad injection group. We find the peak of antibody level of MS strains (HN01strain) groups at14days with the injecton of inactivated vaccine was made of HN strain, on the21days after immynization, S/P values are all more than0.5, which is determined as positive, and antibody level of immune chicken is significantly higher than that of control chicken, which illustrates that isolated strain of MS (HN01strain) has good immunogenicity.