Chemical Biology laboratory, Department of Chemistry, University of Delhi, Delhi, India.
Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India.
Sci Rep. 2017 Mar 17;7:44419. doi: 10.1038/srep44419.
Activation of efflux systems and the formation of biofilm are majorly adapted by microbes to resist antimicrobial agents. PPEF (bisbenzimidazole) targeting topoisomerase IA is observed to be an effective bactericidal agent against both Gram-positive and Gram-negative bacterial strains and thus can be developed as potent broad-spectrum antibiotic against MDR strains. PPEF treatment did not cause target specific mutation instead it leads to up-regulation of efflux gene in E. coli K12 as a mechanism of resistance. Microscopy, fluorescence spectroscopy and flow cytometry result demonstrate higher accumulation of PPEF in efflux gene deleted E. coli K12 mutants, and also suggest that Carbonyl Cyanide 3-Chlorophenylhydrazone (CCCP), resist the efflux of PPEF, and thus increases efficacy of PPEF. Herein, we report, PPEF and CCCP synergistically killed the persistent bacterial cells, which are not killed by PPEF alone. The above two compounds together inhibited biofilm formation, eradicate preformed biofilms and kills the biofilm cells of P. aeruginosa. PPEF and CCCP together reduced bacterial load of E. coli ATCC25922 by 6 log in neutropenic thigh infection model of balb/c mice. Present study suggests that combination therapy could be a promising antimicrobial strategy to handle MDR pathogenic strains.
微生物主要通过激活外排系统和形成生物膜来抵抗抗菌药物。我们观察到，靶向拓扑异构酶 IA 的 PPEF（苯并咪唑）是一种有效的杀菌剂，对革兰氏阳性和革兰氏阴性细菌菌株都有作用，因此可以开发为针对 MDR 菌株的有效广谱抗生素。PPEF 治疗不会导致特定的靶基因突变，而是导致大肠杆菌 K12 中外排基因的上调，作为一种耐药机制。显微镜、荧光光谱和流式细胞术结果表明，在删除外排基因的大肠杆菌 K12 突变体中，PPEF 的积累更高，并且还表明羰基氰化物 3-氯苯腙（CCCP）抵抗 PPEF 的外排，从而提高了 PPEF 的功效。在此，我们报告 PPEF 和 CCCP 协同杀死了持续性细菌细胞，这些细胞不能被 PPEF 单独杀死。这两种化合物共同抑制生物膜形成，根除已形成的生物膜并杀死铜绿假单胞菌的生物膜细胞。PPEF 和 CCCP 联合治疗可使 BALB/c 小鼠中性粒细胞减少性大腿感染模型中的大肠杆菌 ATCC25922 细菌负荷减少 6 个对数级。本研究表明，联合治疗可能是一种有前途的抗菌策略，可用于处理 MDR 致病性菌株。
