1株鸡毒支原体的分离鉴定及致病性研究OA北大核心CSTPCD

In order to study the genetic evolution and pathogenicity of a of Mycoplasma gallisepticum(MG)isolated from chicken farm,a specific band was amplified from suspicious air sac samples collected from a poultry farm in Laixi city of Shandong province using PCR assay with 16S rRNA primers.The purified strain SDMg01 was obtained by bacterial isolation and 16S rRNA gene sequencing.The typical colonies of"poached egg"shape were observed under the low power microscope.Biochemical identification results showed that SDMg01 strain fermented glucose but did not hydrolyze arginine and did not use urea.Phylogenetic analysis based on 16S rRNA sequences was performed by MEGA software.The result demonstrated that SDMg01 strain belonged to MG and clustered in the same branch with other MG strains.The homologies of 16S rRNA nucleotide sequences were 99.8％between SDMg01 strain and MG standard strain(PG31).Then,8-week-old SPF chickens were inoculated with SDMg01 strain.All chickens were observed for clinical signs and pathological changes of air sacs at day 14 post inoculation.The results showed that SDMg01 strain had high pathogenicity and as it induced typical airsacculitis.This study laid a foundation for the development of diagnostic reagents for MG and the screening of vaccine candidate strains.