二烯丙基硫代亚磺酸酯对耐甲氧西林金黄色葡萄球菌的杀菌抑菌作用研究OA

In order to investigate the in vitro bacteriostatic and bactericidal activities of diallyl thiosulfinate(allicin)against methicillin-resistant Staphylococcus aureus(MRSA),and to explore its synergistic mechanism with clinically commonly used antibiotics as well as its inhibitory effect on biofilms,the micro-broth dilution method was adopted to determine the minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of allicin against 7 MRSA strains;the time-kill curves were plotted;the fractional inhibitory concentration index(FICI)was calculated via the checkerboard dilution method;and the crystal violet staining assay was used to detect the biofilm inhibition efficacy.For MRSA ATCC 43300,the MIC and MBC of allicin were 64 μg/mL and 128 μg/mL,respectively.The geometric mean minimum inhibitory concentration(GM-MIC)of 6 clinical isolates was 57.1 μg/mL.At the concentration of 2×MIC,the bacterial colony count decreased by more than 3 log orders within 24 h compared with the baseline at 0 h,achieving a bactericidal rate of no less than 99.9%.The combined application with oxacillin presented a FICI value of 0.375(synergistic effect),while the combination with vancomycin showed a FICI value of 1.000(additive effect).The IC50 for early biofilms was 45.3 μg/mL,and the IC50 for mature biofilms was 98.7 μg/mL.Allicin exerted prominent in vitro bacteriostatic and bactericidal activities against MRSA.It had a synergistic enhancement effect when combined with oxacillin,and exhibited a better inhibitory capacity on early biofilms than mature biofilms.Diallyl thiosulfinate possesses great potential to be developed as a candidate agent against MRSA.