EVALUATION OF THE USE OF ULTRAVIOLET TYPE C RADIATION FOR MICROBIAL AND VIRAL DISINFECTION

Abstract

Emerging as an alternative to manual cleaning and disinfection methods, devices that use ultraviolet C (UVC) light present evidence capable of inactivating a wide spectrum of microorganisms such as bacteria, fungi and viruses. The aim of this study was to evaluate the effectiveness of UVC radiation in microbial and viral disinfection. For this, an experimental study was carried out using a cleaning squeegee composed of two 30 W mercury lamps for sterilization at a distance of 60 mm from the floor. For the antimicrobial evaluation assay, strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were grown on plates containing Mueler Hinton agar and subjected to different doses of UVC radiation (0 mJ/cm², 17.5 mJ/cm², 31.2 mJ/cm², 62.4 mJ/cm² and 175.5 mJ/cm²). For the antiviral evaluation assay, clinical samples with a positive result in RT-qPCR for SARS-CoV-2 were used in and in this case, each sterile plate that contained only these samples received a dose of UVC radiation equal to 0 mJ/cm², 19, 5 mJ/cm², 58.5 mJ/cm², 117.0 mJ/cm² and 175.0 mJ/cm², respectively. In the culture of E. coli there was no growth of the bacteria in any of the doses tested. In the culture of S. aureus, there was the growth of colonies in the dosages of 17.5 mJ/cm² and 31.2 mJ/cm². On the plates containing P. aeruginosa, there was growth at all doses evaluated, with a decrease in the number of colonies along the exposures. As for the viral results, a decrease in viral load can be observed. The use of the squeegee with UVC radiation was effective in disinfecting the bacteria and viruses tested.