江苏省部分地区鸡滑液囊支原体的分离鉴定及致病性和耐药性评价OA北大核心CSTPCD

In order to explore the genotyping,pathogenicity,and aitibiotics susceptibility of My-coplasma synoviae(MS)in selected areas of Jiangsu Province,this study isolated and characterized MS strains.The isolates were identified through observation of colony morphology,serological testing,16S rRNA sequencing,and vlhA-PRR typing.Additionally,SPF chicken challenge tests and antimicrobial susceptibility tests were performed.The results showed that three suspected MS strains were isolated from the collected samples,exhibiting characteristic'fried egg'colonies on solid medium.The 16S rRNA sequence analysis showed that each isolate had 99.9％similarity with MS.Furthermore,plate agglutina-tion test showed that it had agglutination reaction with MS-positive serum and MS-infected serum,but did not react with negative serum of SPF chicken,so it was confirmed that the isolates were MS.The SPF chicken challenge test showed that the three isolates caused obvious joint,foot pad swelling and mild air sac inflammation in chickens,and the symptoms of the joint challenge group were the most obvious.The MIC test showed that,compared to the standard strain MS WVU1853,the three isolates displayed a sig-nificantly reduced sensitivity to tilmicosin and enrofloxacin,as well as varying degrees of reduced sensitivity to tylosin,kitasamycin,tiamulin,lincomycin,florfenicol,and spectinomycin.However,they retained a high sensitivity to valnemulin hydrochloride,doxycycline,oxytetracycline,and tyl-valosin.This study provides scientific basis for local prevention and control of MS infections,offers methodological guidance for the isolation,identification,and aitibiotics selection of clinical MS cases,and lays a research foundation for the establishment of a challenge model in MS vaccine evaluation.