Antibiotic repurposing: bis-catechol- and mixed ligand (bis-catechol-mono-hydroxamate)-teicoplanin conjugates are active against multidrug resistant Acinetobacter baumannii.

Antibiotics that are normally used to treat infections caused by Gram-positive bacteria might be made effective against Gram-negative bacterial infections, if they can circumvent permeability barriers and antibiotic deactivation processes associated with Gram-negative bacteria. Herein we report syntheses of bis-catechol-teicoplanin and mixed ligand catechol-hydroxamate-teicoplanin conjugates. Antibacterial activity assays revealed that conjugation of teicoplanin, which is only known to be active against Gram-positive bacteria, to the siderophore mimics induced potent activity against multidrug resistant strains of select Gram-negative bacteria (Acinetobacter baumannii) while retaining moderate activity against Gram-positive bacteria (Staphylococcus aureus).