Abstract
Objectives: Denture stomatitis is prevalent in older people and poses serious health risks. Ready-to-use (RTU) neutral-pH Electrolysed Oxidizing Water (EOW) is an effective environmental disinfectant used in residential care settings and geriatric wards. However, the influence of storage on stability and effectiveness for denture disinfection has not been established. This research investigated the storage-related stability and antimicrobial activity of RTU EOW, and its efficacy against Candida albicans biofilms formed on denture resin. Methods: The pH, oxidation/reduction potential (mV), available chlorine content (mg/L) and [HOCl] (mM) of RTU EOW (Envirolyte, New Zealand) solutions (n = 22) were measured from bottle opening to 28 days following storage at 4 degrees C, room temperature (RT) or 37 degrees C. Staphylococcus aureus and C. albicans cells were incubated in 80% EOW for contact times (CTs) up to 15 min and colony-forming units (cfu) determined. Minimum inhibitory concentrations (MIC90 EOW-HOCl) after CTs up to five minutes were determined for S. aureus and C. albicans reference strains and clinical isolates. C. albicans-denture resin disc biofilms were assessed after a five-minute CT with undiluted EOW by XTT-metabolic activity assay. Results: [HOCl] remained stable when RTU EOW was stored at 4 degrees C or RT for five months after manufacture. Oneminute CT resulted in log10 cfu reductions of > 6 for S. aureus and > 5 for C. albicans. Mean MIC90 for five-minute CT was 37 mu M (S. aureus) and 54 mu M (C. albicans). Undiluted EOW reduced C. albicans biofilm metabolic activity by 86%. Conclusions: RTU neutral-pH EOW is stable over five-months storage and is an effective denture disinfectant. Clinical significance: The efficacy of the RTU neutral EOW against C. albicans isolates and biofilms formed on denture resin surfaces supports its use as a denture disinfectant and can inform future research to assess its potential for preventing denture-related oral Candida infections in the older population, especially in resourcelimited communities.