中兽医医药杂志2026，Vol.45Issue(3)：14-21,封2,9.DOI:10.13823/j.cnki.jtcvm.2026.019
驴源马链球菌兽疫亚种SYYZ44.1的分离鉴定及致病性研究
Isolation,identification,and pathogenicity of a Streptococcus equi subsp.zooepidemicus isolate SYYZ44.1 of donkey origin
摘要
Abstract
To investigate the pathogenic bacteria of donkey strangles and their biological characteristics in a donkey farm in Kashgar,Xinjiang,this study isolated pathogenic bacteria from 48 nasal swab samples of suspected diseased donkeys.The isolates were purified using sheep blood agar,followed by preliminary identification through Gram staining,microscopic examination and biochemical characterization.Homology analysis was performed via PCR amplification of the 16S rDNA gene,BLAST alignment and phylogenetic tree construction using MEGA 7.0 software.Virulence genes were identified by PCR amplification.Mouse pathogenicity tests were conducted to observe clinical symptoms and mortality,and the median lethal dose(LD50)was determined.The Kirby-Bauer(K-B)disk diffusion method was used to evaluate the antimicrobial susceptibility of the isolate against 12 drugs belonging to 6 categories.The results showed that the isolates of Gram-positive Streptococcus with β-hemolytic activity were isolated from 48 nasal swab samples and a single isolate was selected for intensive research.Sequencing and alignment of the 16S rDNA PCR amplification product revealed that this isolate shared 99%homology with horse-derived Streptococcus equi subsp.zooepidemicus(SEZ)strains from Xinjiang(accession numbers:JQ726499.1 and MT815608.1)and clustered in the same phylogenetic branch,thus being designated as SYYZ44.1.Virulence gene detection indicated that the strain carried FneB,LytA and SeM genes.Antimicrobial susceptibility testing via the K-B method demonstrated that the bacterium was highly sensitive to β-lactam antibiotics(ampicillin,amoxicillin)and rifampicin,but showed low susceptibility to quinolones(ciprofloxacin,norfloxacin)and tetracyclines.In conclusion,this study successfully isolated a donkey-derived Streptococcus equi subsp.zooepidemicus strain named SYYZ44.1,which exhibited strong pathogenicity in mice.β-lactam antibiotics are recommended as the preferred clinical treatment option.The findings of this study provide a theoretical reference for the prevention and control of donkey strangles caused by donkey-derived Streptococcus equi subsp.zooepidemicus infection.关键词
驴腺疫/马链球菌兽疫亚种/毒力基因/致病性/药敏试验Key words
donkey strangles/Streptococcus equi subsp.zooepidemicus/virulence genes/pathogenicity/antimicrobial susceptibility test分类
农业科技引用本文复制引用
高函雅,赵雪婷,靳文婷,王馨,赛福丁·阿不拉,阿得力江·吾斯曼,买占海,张伟,刘丹丹,付恩宁,魏晓龙,罗洁,何莹,吴勇,徐李依娜,崔舒溶,郝宝山..驴源马链球菌兽疫亚种SYYZ44.1的分离鉴定及致病性研究[J].中兽医医药杂志,2026,45(3):14-21,封2,9.基金项目
国家自然科学基金项目(32460901) （32460901）
中央引导地方科技发展专项资金项目(ZYYD2023C03) （ZYYD2023C03）
2023年新疆维吾尔自治区青年基金(2023D01B31) （2023D01B31）
"新疆草食动物新药研究与创制"重点实验室2024开放课题(XJCDVM-HDRC-S202420) （XJCDVM-HDRC-S202420）
新疆维吾尔自治区大学生创新训练计划项目(S202510758013) （S202510758013）
