摘要
为探究利福平(Rif)联合替加环素(Tig)对tet(X6)介导的Tig耐药鲍曼不动杆菌的抑菌作用和机制,本试验采用微量肉汤棋盘稀释法、时间-杀菌曲线、大蜡螟感染模型、Tig相对蓄积量测定、tet(X6)mRNA相对表达量分析、活性氧(ROS)含量测定和耐药突变频率试验,评价Rif和Tig联用对tet(X6)阳性鲍曼不动杆菌的体内外抑菌效果和协同抑菌机制。结果显示,两药联合使用对tet(X6)阳性鲍曼不动杆菌的最佳部分抑菌浓度指数(FICI)为0.3125。与2个单药组相比,联合组明显抑制了tet(X6)阳性鲍曼不动杆菌的生长和菌液浓度。与单独使用Tig相比,Rif和Tig联用显著提高tet(X6)阳性鲍曼不动杆菌胞内的Tig相对蓄积量(P<0.05或P<0.01或P<0.01),极显著降低tet(X6)基因mRNA相对表达量(P<0.01)。与阴性对照组相比,经Rif处理的tet(X6)阳性鲍曼不动杆菌的ROS含量显著降低(P<0.05或P<0.01或P<0.001)。Rif和Tig联合用药对鲍曼不动杆菌的耐药突变频率具有抑制作用。结果表明,Rif通过增加胞内Tig相对蓄积量和降低tet(X6)mRNA相对表达量,协同增强Tig对tet(X6)阳性鲍曼不动杆菌的抑制作用。本试验有望为临床治疗tet(X6)及其变异体阳性鲍曼不动杆菌引起的感染提供新策略。
To investigate the antibacterial activity and underlying mechanism of rifampicin(Rif)combined with tigecycline(Tig)against tet(X6)-mediated Tig-resistant Acinetobacter baumannii(A.baumannii),this study employed checkerboard assays,time-kill kinetics,Galleria mellonella infection model,determination of Tig intracellular accumulation,analysis of tet(X6)mRNA relative expression,reactive oxygen species(ROS)quantification,and resistance mutation frequency assays.These approaches were used to evaluate the in vitro and in vivo antibacterial efficacy and synergistic mechanism of Rif-Tig combination against tet(X6)-positive A.baumannii.The results showed that the optimal fractional inhibitory concentration index(FICI)of the combination against tet(X6)-positive A.baumannii was 0.3125.Compared with either monotherapy,the combination markedly inhibited bacterial growth and decreased bacterial density.Relative to Tig alone,Rif-Tig co-administration significantly increased intracellular Tig accumulation in tet(X6)-positive A.baumannii(P<0.05,P<0.01,or P<0.001)and significantly reduced tet(X6)mRNA expression(P<0.01).Compared with the Negative control,Rif treatment significantly decreased ROS levels in tet(X6)-positive A.baumannii(P<0.05,P<0.01,or P<0.001).The Rif-Tig combination also suppressed the mutation frequency leading to drug resistance.These findings indicate that Rif synergistically enhances the antibacterial effect of Tig on tet(X6)-positive A.baumannii by increasing intracellular Tig accumulation and downregulating tet(X6)mRNA expression.This study provides a promising therapeutic strategy for infections caused by A.baumannii carrying tet(X6)and its variants.
作者
刘志诚
贾照月
韩晴柔
王正阳
杜尚书
晋金蕾
曲丽华
吴帅成
李道稳
刘志海
LIU Zhicheng;JIA Zhaoyue;HAN Qingrou;WANG Zhengyang;DU Shangshu;JIN Jinlei;QU Lihua;WU Shuaicheng;LI Daowen;LIU Zhihai(Tianjin key Laboratory of Agricultural Animal Breeding and Healthy Husbandry,College of Animal Science and Veterinary Medicine,Tianjin Agricultural University,Tianjin 300392,China;College of Chemistry and Pharmacy,Qingdao Agricultural University,Qingdao 266109,China;Pingdu Animal Disease Prevention and Control Center,Qingdao 266109,China;College of Veterinary Medicine,Qingdao Agricultural University,Qingdao 266109,China)
出处
《中国兽医杂志》
北大核心
2025年第12期41-48,共8页
Chinese Journal of Veterinary Medicine
基金
国家自然科学基金(32172911,32302926)
山东省自然科学基金(ZR2024QC093,ZR2023MC129)
天津市自然科学基金(24JCQNJC01290)
山东省青年科技创新团队项目(2021KJ094)
青岛农业大学高层次人才启动基金(6631121042)
中国博士后科学基金(2021M701105)
农业农村部智慧养殖重点实验室(部省共建)开放基金(2023-TJAUKLSBF-2017)。
