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【目的】研究和厚朴酚(HNK)抑制MRSA生物被膜(BF)形成的作用机制。【方法】使用TTC法测定了HNK对供试菌株BF的形成和成熟BF的抑制作用;刚果红平板法定性检测了HNK对PIA合成的影响;分光光度法测定了HNK对供试菌株eDNA释放量的影响;RT-PCR技术检测了HNK对供试菌株icaA、cidA以及agrA基因表达量的影响。【结果】HNK对MRSA 41573 BF的形成和成熟BF均有较强的抑制作用,其中,HNK抑制MRSA 41573 BF形成的MIC和MBC分别为10μg/mL和20μg/mL;抑制成熟BF的MIC和MBC分别为50μg/mL和100μg/mL。当用亚抑菌浓度的HNK与万古霉素联合作用后,可显著提高成熟BF对万古霉素的敏感性。HNK能显著抑制PIA的合成,且呈浓度剂量依赖。HNK能抑制供试菌株eDNA的释放量,其中1/8 MIC的HNK作用供试菌株16 h后,与对照组相比,e DNA的释放量降低了28.3%。HNK可抑制供试菌株BF形成的相关基因,其中1/2 MIC的HNK作用供试菌株16 h后,与对照相比,icaA的表达量降低了59.1%,cidA的表达量降低了56%,agrA的表达量降低了72.3%。【结论】HNK能显著抑制MRSA 41573 BF的形成,其作用机制主要是通过抑制icaA和cidA基因表达量,影响PIA和eDNA的合成,进而抑制BF的形成。此外HNK也可通过调控细菌的QS系统影响BF的形成。
【Objective】 To investigate the mechanism of honokiol (HNK) inhibiting the formation of MRSA biofilm (BF). 【Method】 The inhibitory effect of HNK on the formation of BF and the formation of mature BF were tested by TTC method. The effect of HNK on the synthesis of PIA was determined by Congo red plate assay. The release of HNK to the tested strain was determined by spectrophotometry The effects of HNK on the expression of icaA, cidA and agrA in the tested strains were tested by RT-PCR. 【Result】 HNK inhibited the formation and maturation of MRSA 41573 BF, and MIC and MBC of HNK inhibited the formation of MIC and MBC of mature BF by 10μg / mL and 20μg / mL, respectively 50 μg / mL and 100 μg / mL, respectively. When using sub-bacteriostatic concentrations of HNK in combination with vancomycin, the susceptibility of mature BF to vancomycin can be significantly increased. HNK can significantly inhibit the synthesis of PIA, and dose-dependent manner. HNK inhibited the release of eDNA from the tested strains. After HNK of 1/8 MIC was used for 16 h, the release of e DNA was reduced by 28.3% compared with the control. HNK inhibited the formation of BF in test strains. Hyaluronic acid (HNK) of 1/2 MIC reduced the expression of icaA by 59.1% and decreased the expression of cidA by 56% AgrA expression decreased by 72.3%. 【Conclusion】 HNK can significantly inhibit the formation of MRSA 41573 BF. Its mechanism is mainly through inhibition of icaA and cidA gene expression, affecting the synthesis of PIA and eDNA, and then inhibiting the formation of BF. In addition HNK can also affect the formation of BF by regulating the bacterial QS system.