家蝇抗菌肽MDC协同庆大霉素抗普通变形杆菌作用研究

Synergistic Effect of Musca domestica Cecropin and Gentamicin Against Bacillus proteus vulgaris

以普通变形杆菌(Bacillus proteus vulgaris)为研究对象,探讨家蝇抗菌肽(Musca domestical cecropin,MDC)和庆大霉素(Gentamicin)的体外联合抗菌效果及协同抗菌机制。采用微量肉汤稀释法、棋盘法、结晶紫染色等方法研究两药的协同抗菌作用和抗生物膜作用;通过荧光染色、流式细胞术(FCM)、透射电子显微镜(TEM)观察两药联用的抗菌机制。家蝇抗菌肽MDC与庆大霉素的FIC为0.313,表明两者具有较好的协同抗菌作用;结晶紫染色结果显示两药对细菌初始生物膜、成熟生物膜和胞外蛋白质的影响也有一定的协同作用;荧光和流式细胞术结果显示药物可以有效杀伤细菌,使细菌死亡数目上升;透射电镜观察到给药后大部分细菌细胞壁破损,细胞膜不完整,胞质内容物坏死溶解导致细胞肿胀破裂。家蝇抗菌肽MDC和庆大霉素具有协同抗普通变形杆菌作用,且两药的作用机制相辅相成。

The combined antibacterial action and the synergistic antibacterial mechanism of Musca domestica cecropin(MDC)and gentamicin on Bacillus proteus vulgaris were investigated.Micro broth dilution,chessboard,and crystal violet staining were used to study the synergistic antibacterial and antibiofilm effects of the two drugs.Fluorescence staining,flow cytometry and transmission electron microscopy(TEM)were employed to observe the antibacterial mechanism of the combination of the two drugs.The fractional inhibitory concentration of MDC and gentamicin was 0.313,indicating that the 2 drugs presented promising synergistic antibacterial effect.According to the results of crystal violet staining,the two drugs demonstrated a synergistic effect on the initial biofilm,mature biofilm and extracellular protein of the Bacillus proteus vulgaris.The results of fluorescence and flow cytometry showed that the two drugs efficiently killed bacteria and increased the number of bacterial deaths.TEM observation revealed that most bacterial cell walls were damaged,their cell membranes were incomplete,and intracellular necrosis caused cell swelling and rupture.The MDC and gentamicin act synergistically against Bacillus proteus vulgari,and the mechanism of the two drugs is complementary.