Broad‐Spectrum Antimicrobial and Biofilm‐Disrupting Activity of D7: A Novel Disinfectant Effective Against <i>Pseudomonas aeruginosa</i> and Other Clinically Relevant Pathogens

ABSTRACT Biofilm‐associated contamination and the presence of multiple pathogenic species on environmental and medical surfaces pose a major challenge in healthcare and hygiene management, contributing significantly to hospital‐acquired infections (HAIs). D7 is a multicomponent disinfectant formulated with hydrogen peroxide, quaternary ammonium compounds, and surfactants, which is hypothesized to exert antimicrobial and anti‐biofilm effects. This study aimed to evaluate the inhibitory and eradication effects of D7 on Pseudomonas aeruginosa biofilms, as well as its broad‐spectrum antimicrobial activity and long‐term residual efficacy on treated surfaces. Biofilm inhibition and eradication assays were performed using crystal violet staining and WST viability assays. The antimicrobial spectrum was assessed by disk diffusion assay against Gram‐positive, Gram‐negative, and spore‐forming bacterial strains. Residual antimicrobial activity was evaluated under simulated airborne microbial exposure for extended periods. D7 significantly inhibited biofilm formation at dilutions up to 1000‐fold and eradicated established biofilms at dilutions up to 200‐fold. In addition, D7 demonstrated broad‐spectrum antibacterial activity across all tested species, outperforming conventional disinfectants such as hypochlorous acid, benzalkonium chloride, and ethanol, whose efficacy was markedly diminished upon dilution. Notably, D7 exhibited long‐lasting residual antimicrobial activity on treated surfaces for up to 2 months, preventing microbial recolonization. These results indicate that D7 possesses a combination of strong anti‐biofilm activity, broad‐spectrum antimicrobial efficacy, and sustained surface protection. This suggests its potential as an effective disinfectant and functional antimicrobial coating for preventing biofilm‐associated contamination and reducing infection transmission in healthcare and hygiene‐critical environments. Further studies are warranted to validate its safety and clinical applicability.