Design, construction and robust validation of a germicidal device based on UV irradiation: a necessity for hospital disinfection in the Covid-19 era

Pandemic by SARS-CoV-2 has revealed the importance of disinfection methods to pathogens of medical importance being detectable and infective after several hours on contaminated surfaces, including medical devices. The aim of this work was to design, construct, and validate a UVC light irradiator which operates in the short wavelength region (200 to 320 nm). We studied the effectiveness of the irradiator through in vitro disinfection to eliminate pathogens such as SARS-CoV-2, ESKAPE bacteria and fungi in biofilm and planktonic forms. It was observed that doses of 0.25 J/cm² (10 s of exposure to UVC light) annihilates 100% of ESKAPE bacteria and fungi in planktonic form. Through biofilm formation induction assays of these microorganisms showed resistance to treatment with UV light; however, their viability was not detected after 20 s of exposure (via con focal microscopy). A 100% of reduction for SARS-CoV-2 was reached after 120 s of exposure. This evidence shows the need to employ emerging methods of disinfection of surfaces and medical devices since these are potential vehicles for transmitting pathogens. The advantages of using UV light as an emergent disinfection method in the era of Covid-19 are discussed. (author)