Phosphonium-based disinfectants are as effective as best-in-class quaternary ammonium compounds in the eradication of established biofilms in antibiotic-resistant bacteria

Disinfectants play a crucial role in infection prevention and control, acting as our first line of defense against pathogenic bacteria. Despite biofilms being a major contributor to recalcitrant infections, the development of novel disinfectants often focuses on bacterial growth inhibition. To address this gap, we compared the ability of a structurally diverse set of quaternary ammonium compounds (QACs) and quaternary phosphonium compounds (QPCs) to eradicate biofilms produced by high-priority pathogens: Staphylococcus aureus (MSSA and MRSA), Acinetobacter baumannii , and Pseudomonas aeruginosa . Our findings reveal comparable activity between structurally analogous QACs and QPCs against the panel of five bacteria. Notably, three compounds exhibited improved efficacy against methicillin-susceptible S. aureus (MSSA), community- and hospital-acquired methicillin-resistant S. aureus (MRSA), and A. baumannii (4 to 63 µM) compared with commercially available, benzethonium chloride (BEC), and didecyldimethylammonium chloride (DDAC). Taken together, these results illustrate the need to understand the efficacy of commercial disinfectants in their ability to eradicate biofilms produced by high-priority pathogens to ensure that proper disinfection protocols are designed to prevent the spread of biofilms from high-contact surfaces to patients.