大蒜素与不同抗菌药物联用对耐甲氧西林金黄色葡萄球菌的体外抗菌活性研究

In vitro antibacterial activities of allitricin combined with different antibacterials against MRSA

目的研究大蒜素与抗菌药物联用对耐甲氧西林金黄色葡萄球菌(MRSA)的体外抗菌活性,为临床治疗提供参考依据。方法采用微量肉汤稀释法分别测定大蒜素与抗菌药物对30株MRSA的最低抑菌浓度(MIC),考察单用两药对MRSA的抗菌活性;以测得的单药MIC为依据,采用棋盘法设计,测定并计算大蒜素和抗菌药物联用对30株MRSA的部分抑菌浓度指数(FIC),考察两药联合对MRSA的抗菌活性。结果单用大蒜素对30株MRSA的MIC为(0.30±0.09)mg/mL,与苯唑西林、头孢唑林联用后使其MIC50由64μg/mL和32μg/mL下降到8μg/mL,以协同或相加作用为主;与万古霉素联用后使其MIC50由2μg/mL下降到0.5μg/mL,主要表现为相加作用。结论大蒜素对MRSA有一定抑制作用,与抗菌药物联合后能增强其抑菌效果,临床上可考虑使用大蒜素作为抗菌药物,特别是万古霉素的增敏剂用于治疗MRSA引起的严重感染。

OBJECTIVE To investigate the in vitro antibacterial activities of allitricin combined with different antibacterials against methicillin-resistant Staphylococcus aureus（MRSA）,so as to provide references for clinical treatment.METHODS Thirty strains of MRSA were evaluated for susceptibilities to allitricin and other antibacterials respectively with broth dilution method.According to the minimal inhibitory concentration（MIC）of the two antimicrobials,activities of allitricin combined with other antibacterials against thirty strains of MRSA were evaluated by checkerboard synergy tests and the fraction inhibitory concentration（FIC）index was calculated.The antibacterial activities of allitricin combined with different antibacterials against MRSA were analyzed.RESULTS The MIC of allitricin to thirty strains of MRSA was 0.30±0.09mg/mL.After combining with allitricin,the MIC50 of oxacillin and cefazolin was decreased from 64μg/mL,32μg/mL to 8μg/mL,respectively,showing synergistic or additive effects.Meanwhile,the MIC50 of vancomycin was reduced from 2μg/mL to 0.5μg/mL after the combination of allitricin,mainly demonstrating the additive effect.CONCLUSIONThe MRSA can be partly inhibited by allitricin,and an enhanced antibacterial effect was determined when allitricin was combined with other antibacterials.It is suggested that allitricin has a potential role of antibacterials sensitizing reagents in the treatment of serious infections due to MRSA,especially for vancomycin.