Efficacy of automated disinfection with ozonated water in reducing sink drainage system colonization with Pseudomonas species and Candida auris

Abstract

Sinks in healthcare facilities are a potential reservoir for the dissemination of gram-negative bacilli and Candida spp. 1-4 Addressing sink contamination is challenging because sink drainage systems provide a favorable environment for pathogen colonization and biofilm formation, but they are not amenable to cleaning and disinfection. Disinfection of sinks with agents such as bleach, acetic acid, and hydrogen peroxide have been effective in some studies. 1,2 However, such approaches may be difficult to implement long-term due to the time and effort required and the caustic nature of agents such as bleach. Ozonated water has been reported to be effective in killing many pathogens. 5,6 However, information on the efficacy of ozonated water for sink disinfection is limited. Here, we examined the efficacy of a sink providing automated disinfection with ozonated water against established sink drainage system colonization with Pseudomonas aeruginosa and Candida auris. The SmartFLO3 sink (Franke Kindred, Canada) includes features designed to limit dispersal (eg, a 23-cm-deep bowl) and an enclosed electrode that causes ozonation (0.1-0.35 ppm) and formation of reactive oxygen species in dispensed water. The sink also provides an automated, programmable flush with increased concentration of ozonated water (0.9-2.5 ppm), typically every 4 hours. The sink used in these experiments had access ports in the P-trap and in the drainage pipe distal to the P-trap. According to the manufacturer, the concentrations of ozone produced by the sink are safe for human drinking or bathing and are noncaustic to drain pipes. We tested the efficacy of ozonated water (0.9-0.12 ppm ozone) produced by the sink against a strain of Pseudomonas aeruginosa isolated from a sink at the Cleveland VA Medical Center and 3 strains of Candida auris (MRL#31102, MRL#31103, and AR-BANK#0381). 7 For P. aeruginosa, we used the American Society for Testing and Materials (ASTM) Standard quantitative carrier

Ozonized Water in Microbial Control: Analysis of the Stability, In Vitro Biocidal Potential, and Cytotoxicity

“…Although a recent study demonstrated C. auris resistance toward low concentrations and low exposure time of gaseous ozone [87], another study concluded a higher efficacy of repeated exposure of aqueous ozone, reducing the contamination of this yeast at a concentration range of 0.9-0.1 ppm [88], which is similar to the optimal concentration of 0.8 ppm in the present study. Considering this and the current efficacious use of dissolved ozone in many therapeutic and disinfecting procedures, ozonized tap water may be efficiently included in technologies for disinfection.…”

Effectiveness of foam disinfectants in reducing sink-drain gram-negative bacterial colonization

“…Many of the other methods used to control outbreaks related to sinks may be costly, labor intensive, and difficult to implement rapidly. These approaches have included placing barriers between sinks and work areas, 6 reducing water flow pressure, 6 ozonation of water, 18 heating and/or sonicating the drain stem, 9,[19][20][21] replacing the P-trap, 9,10,22 and complete elimination of sinks. 23 Another approach that could be implemented rapidly in outbreak settings is the use of disposable plastic sink drain covers that reduce dispersal of organisms from sink drains.…”

Candida auris—the growing menace to global health

“…For oral decolonisation, 0.2% chlorhexidine mouthwash has been used, also chlorhexidine‐impregnated protective discs for central vascular catheter exit sites have been found effective to reduce line‐associated C. auris bloodstream infections . For decolonisation of C. auris in sink drainage systems, ozonated water has been effectively used . Compared to planktonic cells, C. auris biofilms showed reduced sensitivity to commonly used disinfectants such as povidone iodine, chlorhexidine and hydrogen peroxide …”