牛源金黄色葡萄球菌的分离鉴定、毒力基因检测与耐药性分析

Isolation, identification, virulence gene detection and antimicrobial resistance analysis of bovine-derived Staphylococcus aureus

    摘要
  • 摘要:
    目的 调查新疆昌吉回族自治州规模化奶牛场乳房炎金黄色葡萄球菌流行分布，开展菌株分离鉴定、药敏试验、毒力基因 PCR 检测及小鼠致病性试验，明确本地牛源金葡菌流行特征、耐药表型、毒力基因携带与致病能力，为奶牛乳房炎临床防控与科学用药提供理论依据。
    方法 采集 184 份乳房炎乳汁样品，采用细菌分离纯化、革兰氏染色、16S rRNA 测序完成菌种鉴定；采用 K-B 纸片扩散法检测菌株耐药谱，PCR 扩增检测 6 种关键毒力基因，小鼠腹腔攻毒试验验证致病性。
    结果 184 份乳样共分离 26 株金黄色葡萄球菌，分离率 14.13%；菌株对头孢噻肟、四环素、氯霉素、多粘菌素 B、庆大霉素、氟苯尼考、复方新诺明、环丙沙星敏感率均超 90%；共检出nuc、PVL、hla、hlb、FnBPA、FnBPB 6 种毒力基因，检出率依次为 100%、76.9%、100%、84.6%、100%、80.8%，共形成 5 种基因谱型，其中nuc-PVL-hla-hlb-FnBPA-FnBPB组合占比 53.8%；携带多毒力基因菌株致病性较强。
    结论 该牧场存在金黄色葡萄球菌乳房炎流行风险；分离菌株整体耐药程度低，但菌株普遍携带多种毒力基因、基因型多样，整体菌株致病力较强。

     

    Abstract:
    Objective To investigate the prevalence distribution of Staphylococcus aureus isolated from mastitis cases in large-scale dairy farms in Changji Prefecture, Xinjiang, and conduct strain isolation and identification, antimicrobial susceptibility testing, PCR detection of virulence genes and mouse pathogenicity tests. This study aims to clarify the epidemiological characteristics, antimicrobial resistance phenotypes, virulence gene profiles and pathogenic capacity of bovine-derived S. aureus in the local area, and provide theoretical references for clinical prevention and control as well as rational antimicrobial use against bovine mastitis.
    Methods A total of 184 milk samples from mastitic dairy cows were collected. Bacterial isolation and purification, Gram staining and 16S rRNA sequencing were performed for species identification. The Kirby-Bauer (K-B) disk diffusion method was used to detect the antimicrobial resistance spectrum of isolates. PCR amplification was applied to screen six key virulence genes, and intraperitoneal challenge tests in mice were carried out to verify bacterial pathogenicity.
    Results Twenty-six strains of Staphylococcus aureus were isolated from 184 milk samples, with an isolation rate of 14.13%. The isolates exhibited susceptibility rates above 90% to cefotaxime, tetracycline, chloramphenicol, polymyxin B, gentamicin, florfenicol, cotrimoxazole and ciprofloxacin. Six virulence genes including nuc, PVL, hla, hlb, FnBPA and FnBPB were detected, with positive rates of 100%, 76.9%, 100%, 84.6%, 100% and 80.8%, respectively. Five distinct virulence gene profiles were identified, among which the nuc-PVL-hla-hlb-FnBPA-FnBPB genotype accounted for 53.8%. Strains carrying multiple virulence genes showed strong pathogenicity.
    Conclusion There is an epidemic risk of mastitis caused by Staphylococcus aureus on this dairy farm. The isolated strains show low overall antimicrobial resistance, but widely carry diverse virulence genes with abundant genotypes, and possess strong pathogenicity.

     

    • HTML全文
    • 参考文献(26)
    • 相关文章
    • 施引文献
  • 资源附件(0)

/

返回文章
返回