酶标比浊法评价月桂酸单甘油酯对肉葡萄球菌的抑菌活性

以分离自鱿鱼丝的肉葡萄球菌S1为试验菌株,采用酶标比浊法测定了月桂酸单甘油酯(GML)、乳酸链球菌素(Nisin)、双乙酸钠、柠檬酸和山梨酸钾对试验菌的最低抑菌浓度(MIC),GML的抑菌生长曲线,以及GML与Nisin、双乙酸钠和柠檬酸复配物对试验菌的抑菌增效性;结合涂布计数法确定选用抑菌剂的最低杀菌浓度(MBC)及GML对试验菌的动态杀菌曲线。试验结果表明:GML对试验菌的MIC和MBC分别为25μg/mL和50μg/mL,均低于其它抑菌剂;GML对试验菌抑制生长曲线及动态杀菌曲线表明,较低浓度的GML的存在即可有效延长试验菌的延滞期,2×MBC浓度的GML可在4.5h内使试验菌全部失活;同时,GML与Nisin、柠檬酸和双乙酸钠均显示出较好的复配增效性。GML对试验菌具有极强的抑制作用,且与多种抑菌剂显示出较好的增效性。

Evaluating of Antimicrobial Activity of Glycerol Monlaurate Against Staphylococcus Carnosu with the Microplate Reader

A microtiter plate assay is employed to systematically assess the minimum inhibitory concentrations(MIC) of glycerol monlaurate(GML) and many other preservatives to Staphylococcus carnosu S1,isolated from squid thread.The growth curves of Staphylococcus carnosu S1 and the MIC of the combinations of GML and other preservatives are obtained with this method.At the same time,the minimum bactericidal concentration(MBC) of the selected preservatives against Staphylococcus carnosu S1 and the killing-curves of Staphylococcus carnosu S1,exposed to various concentration of GML are conducted using colony counting method.The results show that the MIC and the MBC of GML to Staphylococcus carnosu S1 is 25 μg/mL and 50 g/mL,respectively,lower than the Nisin,sodium diacetate and citric acid.The growth curves and the killing-curves of Staphylococcus carnosu S1,treated with various concentration of GML,indicate that the growth of Staphylococcus carnosu S1 is effectively restrained and the lag phase is extended with the existence of low concentration of GML.And all of the tested strains are deactivated at the concentration of 2 ×MBC within 4.5 h.Meanwhile,GML acts synergistically effects against Staphylococcus carnosu S1,mixtured with Nisin,citric acid and sodium diacetate,respectively.Therefore a strong inhibition of GML on Staphylococcus carnosu S1 is demonstrated.