Nature-inspired Novel Quaternary Ammonium Compounds: Synthesis, Antibacterial and Antibiofilm Activity.

Inspired by marine compounds isolated from sponges and the increased need for new effective antimicrobials, novel quaternary ammonium compounds with long alkyl chains (C8-C12) were designed and synthesized. Antibacterial and antibiofilm activity of new compounds was evaluated against six microbial strains (S. aureus, E. coli, and P. aeruginosa). All synthesized ammonium salts displayed antibacterial activity with MIC values ranging from 5.0 to 25.0 μg/mL. In addition, most compounds showed strong inhibition of biofilm formation of S. aureus ATCC 25923, P. aeruginosa PA01, and colistin-resistant P. aeruginosa (CRPA) at a concentration of 5.0 μg/mL. Ammonium salt 3 showed 100 % inhibitory activity against all tested bacterial biofilms except that of colistin-resistant S. aureus (CRSA).