Three novel highly charged copper-based biocides: safety and efficacy against healthcare-associated organisms

Area of Science:

• Inorganic chemistry
• Microbiology
• Biotechnology

Background:

• Healthcare-associated infections (HAIs) pose a significant threat.
• Novel antimicrobial agents are needed to combat resistant pathogens.
• Copper-based compounds have known antimicrobial properties.

Purpose of the Study:

• To evaluate three novel highly charged copper-based inorganic biocidal formulations.
• To assess their efficacy against key HAI-associated microorganisms.
• To determine their safety profile and decontamination capabilities.

Main Methods:

• Time-kill assays were performed against clinical isolates including methicillin-resistant Staphylococcus aureus (MRSA), Legionella pneumophila, Acinetobacter calcoaceticus/baumannii (ACCB), and Clostridium difficile spores.
• Decontamination efficacy on ultramicrofibre (UMF) cloths was tested.
• Cytotoxicity assays were conducted on human skin and intestinal epithelial cells.

Main Results:

• All formulations demonstrated potent biocidal activity at concentrations as low as 1 ppm against both stationary- and log-phase organisms.
• Complete eradication (>6 log10) of MRSA and ACCB was achieved within 1 hour at 150 ppm.
• The formulations effectively decontaminated UMF cloths contaminated with MRSA, ACCB, or C. difficile spores.
• No cytotoxicity was observed in human epithelial cells up to 100-200 ppm.

Conclusions:

• The novel copper-based biocidal formulations exhibit potent antimicrobial activity against critical HAI pathogens.
• These formulations are effective in decontaminating surfaces and are safe for human epithelial cells.
• The biocidal efficacy is attributed to the novel formulations, not merely their copper sulphate or inorganic binder components.