万古霉素联合阿奇霉素对形成生物被膜耐甲氧西林金黄色葡萄球菌的体外抗菌效果分析

In vitro antimicrobial effect of Vancomycin combined with Azithromycin on Methicillin-resistant Staphylococci aureus with biofilm

摘要:

目的  探讨体外万古霉素与阿奇霉素联合应用对形成生物被膜的耐甲氧西林金黄色葡萄球菌（MRSA）的抗菌效果。方法  使用头孢西丁纸片扩散法和MRSA胶乳凝集实验确定MRSA，采用刚果红培养基判断生物被膜的形成，通过肉汤稀释法将万古霉素和阿奇霉素进行棋盘格联合药敏试验，测出不同浓度下的抑菌指数（FIC），据此判定两药联用后所呈现出的相关效应。结果  万古霉素和阿奇霉素联用组最小抑菌浓度（MIC）明显低于各单药组，两药联用主要表现为相加作用（88.2%）和协同作用（11.8%），无无关作用和拮抗作用。相加作用时FIC为0.5～1.0；协同作用时FIC≤0.5。结论  万古霉素联用阿奇霉素对生物被膜形成的MRSA具有明显的体外抑菌效果，可以指导临床有效地降低药物使用剂量，减少毒副作用。

Abstract:

Objective To explore the in vitro antimicrobial effect of Vancomycin combined with Azithromycin on Methicillin-resistant Staphylococci aureus (MRSA) with biofilm. Methods MRSA were detected using Cefoxitin disk diffusion method and MRSA latex agglutination test. Biofilm was detected using Congo red medium. Fractional inhibitory concentration (FIC) of Vancomycin combined with Azithromycin was detected by broth dilution checkerboard joint susceptibility testing, which could show the related effects. Results The minimal inhibitory concentration (MIC) of Vancomycin combined with Azithromycin was significantly lower than that of each drug alone; the combined medication showed additive effect (88.2%) and synergistic effect (11.8%), but no irrelevant or antagonism effect. Additive effect was decided when FIC value was 0.5-1.0. Synergistic effect was decided when FIC value was ≤ 0.5. Conclusions The in vitro inhibitory effect of Azithromycin combined with Vancomycin against MRSA with biofilm is obvious, which can effectively reduce the clinical doses and the side effects of the drugs.