The small molecule IITR08027 restores the antibacterial activity of fluoroquinolones against multidrug-resistant Acinetobacter baumannii by efflux inhibition
The small molecule IITR08027 restores the antibacterial activity of fluoroquinolones against multidrug-resistant Acinetobacter baumannii by efflux inhibition
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DOI：
10.1016/j.ijantimicag.2017.03.005
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发表时间：
2017-08-01
影响因子：
10.8
通讯作者：
Pathania, Ranjana
中科院分区：
文献类型：
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作者：
Bhattacharyya, Tapas;Sharma, Atin;Pathania, Ranjana
外排泵是多重耐药的主要决定因素之一。本研究将鲍曼不动杆菌多药外排泵基因AbeM克隆到多拷贝质粒pUC 18中，并转化大肠杆菌外排泵缺陷株KAM 32。重组E.利用大肠杆菌中的环丙沙星筛选8000个分子的小分子文库以鉴定IITR08027，IITR08027是一种本身没有抑制作用但可以增强环丙沙星活性的小分子。当与A结合使用时。鲍曼不动杆菌，该分子提高了环丙沙星的杀伤效率，延长了其抗生素后效应，并导致抗生素抗性突变体选择频率的降低。基于奎纳克林的荧光猝灭和膜去极化测定显示，IITR08027作为质子梯度抑制剂起作用。这延长了IITR08027对其他H+驱动外排泵（如AbeS）的活性。对HeLa和HEK293细胞的MTT测定表明，该分子在其最低有效浓度下是无毒的。我们认为，IITR08027与氟喹诺酮类药物（环丙沙星和诺氟沙星）联合使用可能对多药耐药的A。表达AbeM的鲍曼不动杆菌或使用质子梯度作为外排机制的其它外排泵。(C)2017 Elsevier B.V.和国际化疗学会。All rights reserved.
Efflux pumps are one of the major determinants of multiple drug resistance. In this study, AbeM, amultidrug efflux pump in Acinetobacter baumannii, was cloned into a multicopy plasmid (pUC18) and was transformed into an efflux-deficient mutant of Escherichia coli (KAM32). The elevated resistance profile of the recombinant E. coli for ciprofloxacin was utilised to screen a small-molecule library of 8000 molecules to identify IITR08027, a small molecule that is not inhibitory on its own but that could potentiate the activity of ciprofloxacin. When used in combination against A. baumannii, the molecule improves the killing efficiency of ciprofloxacin, extends its post-antibiotic effect and causes a decrease in frequency of resistant mutant selection with the antibiotic. Quinacrine-based fluorescence quenching and membrane depolarisation assays revealed that IITR08027 functions as a proton gradient inhibitor. This extends the activity of IITR08027 against other H+-driven efflux pumps such as AbeS. MTT assay against HeLa and HEK293 cells suggested that the molecule is non-toxic at its minimum effective concentration. We propose that, in combination with fluoroquinolones (ciprofloxacin and norfloxacin), IITR08027 may be effective against multidrug- resistant A. baumannii expressing AbeM or other efflux pumps that use the proton gradient as an efflux mechanism. (C) 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.