Antimicrobial Effect of a Novel Chitosan Derivative and Its Synergistic Effect with Antibiotics

Cationic polymers are promising antibacterial agents because bacteria have a low propensity to develop resistance against them, but they usually biocompatibility of their hydrophobic moieties. Herein, we report new biodegradable and biocompatible chitosan-derived cationic polymer, 2,6-diamino chitosan (2,6-DAC). 2,6-DAC shows excellent broad-spectrum antimicrobial activity with minimum inhibitory concentrations (MICs) 8-32 μg/mL clinically relevant multidrug-resistant (MDR) including Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii. Furthermore, an synergistic effect various antibiotics proved by decreasing the MICs MDR A. baumannii methicillin-resistant aureus 2.4 log10 reduction in murine intraperitoneal lung infection models. The novel derivative, 2,6-DAC, can be utilized as agent alone or combination antibiotics.