【摘要】 本文考察了nisinA对奶牛乳腺炎葡萄球菌生物被膜的形成及相关基因表达的影响。结果表明,亚抑菌浓度的nisinA对金黄色葡萄球菌SMS10和表皮葡萄球菌SMSE169的生长和生物被膜的形成都起到明显的抑制作用;当nisinA的浓度为8×MIC和16MIC时,其对菌株已形成的成熟生物被膜也具有良好的消除作用;采用电镜可以观察到经nisinA处理的生物被膜的密度和厚度显著降低,不仅出现了明显空隙,而且可见单个分散的菌体细胞。实时荧光定量PCR结果表明,相比于对照组,nisinA处理组的ica D,agr基因的表达显著提高,clfB基因的表达却显著下降,而关于RNAIII基因的表达情况,2株菌呈现出不同的变化趋势,显示出生物被膜基因调控的复杂性。nisinA天然、安全、高效等特点,将在奶牛乳房炎的预防和治疗上具有良好的开发前景。更多还原

【Abstract】 In the present study,nisinA was tested for its capability to interfere with the biofilm formation and its related gene expression of bovine mastitis staphylococcus.The results showed that subinhibitory dosages of nisinA could significantly inhibit the growth and biofilm formation of S.aureus SMS10 and S.epidermidis SMSE169.Also,nisinA had the eradicating effect on formed mature biofilm when the concentration was 8×MIC and 16 MIC.After treatment with nisinA,the density and thickness of the biofilm was decreased,and an obvious gap as well as the single dispersed bacteria cells was seen by electron microscopy.Compared with the control group,the transcriptional level of ica D and agr genes was up-regulated,while clfB gene was down-regulated.For RNAIII gene,the two of strains presents different results,which showed the complexity of the gene regulatory mechanism for biofilm formation.In future,nisinA would have a good prospect in prevention and treatment of dairy cow mastitis as its advantages of nature,safety and high efficiency.更多还原