Synergy between Synthetic Antimicrobial Polymer and Antibiotics:A Promising Platform to Combat Multidrug-resistant Bacteria


The failure of many antibiotics in the treatment of chronic infections caused by multidrug-resistant (MDR) bacteria necessitates the development of effective strategies to combat this global healthcare issue. Here, we report an antimicrobial platform based on the synergistic action between commercially available antibiotics and a potent synthetic antimicrobial polymer that consists of three key functionalities: low-fouling oligoethylene glycol, hydrophobic ethylhexyl, and cationic primary amine groups. Checkerboard assays with Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli demonstrated synergy between our synthetic antimicrobial polymer and two antibiotics, doxycycline and colistin. Coadministration of these compounds significantly improved the bacteriostatic efficacy especially against MDR P. aeruginosa strains PA32 and PA37, where the minimal inhibitory concentrations (MICs) of polymer and antibiotics were reduced by at least 4-fold. A synergistic killing activity was observed when the antimicrobial polymer was used in combination with doxycycline, killing >99.999% of planktonic and biofilm P. aeruginosa PAO1 upon a 20 min treatment at a polymer concentration of 128 μg mL -1 (4.6 μM) and doxycycline concentration of 64 μg mL -1 (133.1 μM). In addition, this synergistic combination reduced the rate of resistance development in P. aeruginosa compared to individual compounds and was also capable of reviving susceptibility to treatment in the resistant strains.

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Divisions: College of Health & Life Sciences > School of Optometry > Optometry
Additional Information: This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Infectious Diseases, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see
Uncontrolled Keywords: RAFT polymerization,antibiotic resistance,antimicrobial polymers,biofilm,combination therapy,Infectious Diseases
Publication ISSN: 2373-8227
Last Modified: 21 Jun 2024 07:14
Date Deposited: 09 Apr 2019 09:13
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Related URLs: ... nfecdis.9b00049 (Publisher URL)
http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Article
Published Date: 2019-08-09
Published Online Date: 2019-04-02
Accepted Date: 2019-02-04
Authors: Namivandi-Zangeneh, Rashin
Sadrearhami, Zahra
Dutta, Debarun (ORCID Profile 0000-0002-2204-5272)
Willcox, Mark
Wong, Edgar H H
Boyer, Cyrille



Version: Accepted Version

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