Radio catalytic ionization: an innovative approach for indoors disinfection

Is infection of indoors is a crucial problem, particularly in healthcare settings for preventing healthcare-associated infections. Recent methods, based on the Radio Catalytic Ionization (RCI), emerged as a possible approach to disinfect the environments. The aim is to test the efficacy of a RCI device to control microbial contamination on a confined setting. Methods A pre/post design study was conducted from January to April 2015 in a laboratory of the University of Siena, Italy. RCI system transforms air moisture in Reactive Oxygen Species, including H2O2, trough a photo-catalytic process, mediated by an ultraviolet light which irradiates a titanium dioxide surface. The device was tested with three levels of humidity: 35–40%, 50–60% and >60%. Efficacy on disinfection was assessed counting the number of Colony Forming Unit (CFU) on two shelves trough contact plates incubated at 36C and read at 48 h from sampling. Comparisons were performed during the activity/inactivity of the device at different levels of humidity. Moreover, it was studied the effect of the RCI device in time. Linear regression, ANOVA and Wilcoxon paired sample tests were performed for evaluating possible differences. Results When the humidity was around 35–40% the device tended to contrast the contamination level (below 30 CFU). Similar results were achieved when the humidity level was set at 50– 60%; when the level of humidity was higher (>60%), it was noted a significant decreasing trend of microbial contamination that ended up with 10–5 CFU. The reduction of CFU occurred after a latency of 2–3 days of continue exposition (linear regression showed a coefficient 3.70 with p < 0.0001). Conclusion Reduction of the number of CFU seems to correlate with the percentage of moisture of the air, particularly when the values were above 60%; low levels of humidity seem to control the microbial contamination. Confined environments with controlled humidity level could benefit of RCI system.