Redox-active cationic organoiron complex: a promising lead structure for developing antimicrobial agents with activity against Gram-positive pathogens including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium

We report a new class of antimicrobial agent, a redox-active, cationic organometallic, eta(6)-arene-eta(5)-cyclopentadienyliron(II) complex, with activity against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium. Structure-property relationship investigations revealed that the antimicrobial activity against these pathogens, especially methicillin-resistant Staphylococcus aureus, is tunable. The ability of this new class of antimicrobial agent to induce cellular oxidative stress was confirmed using dichlorodihydrofluorescein assay. We attributed the induction of oxidative stress as a mechanism that contributes to the overall antimicrobial activity of these compounds. Generally, this antimicrobial agent was non-toxic to BJ fibroblast cell lines at <= 28 mu g mL(-1). The eta(6)-arene-eta(5)-cyclopentadienyliron(II) complex represents a potential lead structure for the development of topical antimicrobial therapeutics to combat resistant strains of Gram-positive bacteria.