DataSheet_1_SPR741, Double- or Triple-Combined With Erythromycin and Clarithromycin, Combats Drug-Resistant Klebsiella pneumoniae, Its Biofilms, and Persister Cells.docx

Klebsiella pneumoniae has emerged as a major clinical and public health threat owing to the increasing prevalence of healthcare-associated infections caused by multidrug-resistant or extensively drug-resistant strains. However, increasing antibiotic resistance and the absence of clinically effective antimicrobial agents make combination therapy an urgent need. This study investigated the anti-microbial activity of SPR741, a polymyxin B derivative, in combination with macrolide antibiotics (erythromycin and clarithromycin), against extensively drug-resistant and pandrug-resistant K. pneumoniae. Monotherapy, double, and triple combination therapies were performed to identify the most effective treatment combination using in vitro checkerboard, time-killing kinetics. Furthermore, we evaluated the biofilm eradication and persister cell-killing activity of these combinations using laser confocal microscopy and colony forming unit counting. In addition, a neutropenic mouse thigh infection model was used to assess the therapeutic efficacy and toxicity of the triple antibiotic combination against pandrug-resistant K. pneumoniae in vivo. Our results suggested that SPR741 combined with macrolides exhibited strong synergistic antibacterial activity against extensively drug-resistant and pandrug-resistant K. pneumoniae. These antibiotic combinations could also effectively eradicate highly resistant bacterial biofilms and persister cells in vitro and demonstrate considerable efficacy and low toxicity in vivo. In summary, our findings indicated that SPR741, in combination with macrolide antibiotics (double or triple combination), has the potential to serve as a novel treatment option against drug-resistant K. pneumoniae -related infections.

肺炎克雷伯菌（Klebsiella pneumoniae）已成为临床与公共卫生领域的重大威胁，这源于多重耐药或广泛耐药菌株引发的医院获得性感染患病率持续攀升。然而，抗生素耐药性不断加剧，且临床缺乏有效的抗菌药物，使得联合疗法成为迫切需求。本研究针对多粘菌素B衍生物（polymyxin B derivative）SPR741与大环内酯类抗生素（macrolide antibiotics，含红霉素erythromycin、克拉霉素clarithromycin）联合使用时的抗菌活性展开探究，受试菌株为广泛耐药及泛耐药肺炎克雷伯菌。本研究通过体外棋盘稀释法（checkerboard）与时间杀菌动力学（time-killing kinetics）实验，开展单药、双药及三药联合疗法实验以筛选最优治疗组合；此外，本研究借助激光共聚焦显微镜（laser confocal microscopy）与菌落形成单位计数（colony forming unit counting）法，评估了上述联合疗法对细菌生物膜的清除效果及持留菌杀灭活性。同时，本研究构建中性粒细胞减少小鼠大腿感染模型（neutropenic mouse thigh infection model），在体内水平评估三药联合抗生素疗法对抗泛耐药肺炎克雷伯菌的治疗效果与毒性反应。研究结果显示，SPR741与大环内酯类药物联合使用时，对广泛耐药及泛耐药肺炎克雷伯菌展现出显著的协同抗菌活性；上述抗生素联合疗法还可在体外有效清除高耐药性细菌生物膜与持留菌，并在体内展现出优异疗效与低微毒性。综上，本研究结果表明，SPR741与大环内酯类抗生素联合使用（双药或三药联合方案）有望成为治疗耐药肺炎克雷伯菌相关感染的新型疗法。