中药单体白花丹醌对替加环素耐药鲍曼不动杆菌的抗菌作用研究

目的 比较5种中药单体对替加环素耐药鲍曼不动杆菌的体外抗菌作用,探讨替加环素与中药单体联合用药的增敏作用及相关作用机制.方法 采用琼脂二倍稀释法和微量肉汤法,检测鲍曼不动杆菌对14种抗菌药物的最低抑菌浓度(MIC).检测中药单体白花丹醌、二氢丹参酮、葫芦素、盐酸小檗碱和紫胡皂苷d对替加环素耐药鲍曼不动杆菌的抑菌作用;用棋盘法测定白花丹醌联合替加环素MIC值,计算部分抑菌浓度指数值(FICI).选取CCCP、PAβN及白花丹醌作为外排泵抑制剂,观察外排抑制试验结果.结果 临床分离的120株鲍曼不动杆菌对12种抗菌药物均有不同程度耐药,对米诺环素的耐药率相对较低,对多粘菌素B全部敏感,其中,有8株替加环素耐药菌.5种中药单体中白花丹醌对替加环素耐药菌株抑菌活性最佳,MIC值范围是16~32 μg/mL.白花丹醌和替加环素联合试验中,白花丹醌可逆转部分替加环素耐药鲍曼不动杆菌耐药性,75%(6/8)表现为相加作用,25%(2/8)表现为无关作用.外排抑制试验中,CCCP、PAβN及白花丹醌均显示对替加环素有一定的增敏作用.结论 在体外环境下,白花丹醌对替加环素耐药鲍曼不动杆菌具有一定抑菌活性,联合替加环素可降低替加环素耐药鲍曼不动杆菌耐药性,其增加抗菌药物敏感性的作用可能与外排泵抑制有关.

A Study on the Antibacterial Effect of Chinese Medicine Plumbagin on Tigecycline-Resistant Acinetobacter Baumannii

Objective To investigate the in vitro antibacterial effect of five Traditional Chinese Medicine (TCM) monomers on tigecycline-resistant Acinetobacter baumannii and explore the bacterial sensitizing enhancement effect of tigecycline in combination with these monomers and the related mechanism.Methods Minimum inhibitory concentration (MIC) of 14 antimicrobial agents for 120 clinical isolates of A.baumannii was measured by the methods of agar dilution and broth microdilution.The antibacterial activity of the TCM monomers including plumbagin, dihyd rotanshinone, cucurbitacin, berberine hydrochloride and saikosaponin-d against tigecycline-resistant A.baumannii was investigated.The MIC value of plumbagin combined with tigecycline was determined by the chessboard method and the fractional inhibitory concentration (FIC) index was further calculated.The efflux pump inhibitors involving CCCP, PAβN and plumbagin were used to evaluate the bacterial efflux inhibition effect.Results The resistance to 12 antimicrobial agents was found in all the 120 clinical isolates to different degrees, ranging from the relatively low resistance of minocycline to the complete sensitivity of polymyxin B.Among them, eight tigecycline-resistant isolates were identified.Plumbagin displayed the best antibacterial activity in the five TCM monomers with the MIC value of 16~32μg/ml.Plumbagin could reverse the partial resistance of tigecycline-resistant Acinetobacter baumannii as demonstrated by plumbagin-tigecycline combination, which showed 75% (6/8) additive effect and 25% (2/8) irrelevant effect.In the efflux inhibition test, CCCP, PAβN and plumbagin all showed certain degree of sensitizing enhancement effect to tigecycline.Conclusion The in vitro plumbagin has a certain antibacterial activity against tigecycline-resistant Acinetobacter baumannii;the plumbagin-tigecycline combination can reduce the resistance of tigecycline-resistant Acinetobacter baumannii;the sensitization effect of plumbagin may be related with the efflux pump inhibition.