Musca domestica cecropin协同头孢曲松钠抗鼠伤寒沙门氏菌及生物被膜作用研究

目的 研究家蝇抗菌肽cecropin (Musca domestica cecropin, MDC) 和头孢曲松钠的协同抗鼠伤寒沙门氏菌作用及抗生物被膜作用。方法 采用微量肉汤稀释法、棋盘法、结晶紫染色等方法研究2种药的协同抗菌效果和抗生物被膜作用;用荧光染色、流式细胞术(FCM)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)观察联合用药的抗菌机制。结果 棋盘法计算FIC指数为0.218,结果表明MDC与头孢曲松钠之间存在协同抗菌作用;96孔板法联合结晶紫染色等结果显示联合用药对鼠伤寒沙门氏菌初始生物被膜具有抑制作用,并且能协同破坏成熟生物被膜;采用荧光染色与流式细胞术考察细胞膜的完整性,同浓度下MDC组对细胞膜的破坏为47%,头孢曲松钠组为30%,联合组能破坏89%的细胞膜。扫描电子显微镜和透射电子显微镜观察到联合用药组中细菌细胞壁破损,细胞膜不完整,胞质内容物坏死溶解导致细胞肿胀破裂,药效强于单独用药组。 体外联合使用抗菌肽MDC与头孢曲松钠具有协同抗鼠伤寒沙门氏菌及生物被膜的作用。

Musca domestica cecropin synergizes with ceftriaxone sodium anti-Salmonella typhimurium and has an anti-biofilm effect

The synergistic anti-Salmonella typhimurium and anti-biofilm effects of Musca domestica cecropin(MDC)and ceftriaxone sodium were studied in this article.The synergistic antimicrobial effect and antibiofilm effect of the two drugs were studied with the microbroth dilution method,chessboard method and crystal violet staining.The antimicrobial mechanism effect of the combination was observed through fluorescence staining,flow cytometry,scanning electron microscopy and transmission electron microscopy.The FIC index calculated with the chessboard method was 0.218.The results showed a synergistic antimicrobial effect between MDC and ceftriaxone sodium.The 96-well plate method combined with crystal violet staining showed that the combination of drugs inhibited the formation and initial attachment of S.typhimurium biofilm and had a synergistic destructive effect on mature biofilm.The cell membrane integrity was investigated with fluorescence staining and flow cytometry.At the same concentrations,the damage to the cell membrane was 47%in the MDC group,30%in the ceftriaxone sodium group and 89%in the combined group.Scanning electron microscopy and transmission electron microscopy showed that the bacterial cell wall was damaged,the cell membrane was incomplete,and the cytoplasm was necrotic and dissolved,thus resulting in cell swelling and rupture;the combined treatment was more effective than treatment with either drug alone.The combination of the antimicrobial peptide MDC and ceftriaxone sodium in vitro has synergistic anti-S.typhimurium and anti-biofilm effects.