Evaluation of the Efficacy of UV-C Radiation in Eliminating Clostridioides difficile from Touch Surfaces Under Laboratory Conditions

<i>Clostridioides difficile</i> (CD) is a Gram-positive, spore-forming anaerobic bacterium, usually transmitted through the fecal-oral route, that can result from direct person-to-person contact, exposure to contaminated environmental surfaces, or contact with the hands of colonized healthcare personnel. An increased number of infections, especially healthcare-associated, with this etiology has been observed in most countries. As a spore-forming organism, CD is resistant to alcohol formulations and is a challenge for chemical disinfection. The solution could be the supplementation of traditional disinfection with non-touch techniques, such as UV-C radiation. The adoption of UV-C as a supplementary disinfection method in hospitals has significantly increased since the COVID-19 pandemic. However, there are no current guidelines concerning the use of UV-C disinfection in hospitals. The aim of this study was to evaluate the effectiveness of UV-C irradiation in inactivating <i>Clostridioides difficile</i> from different types of surfaces in hospital settings. The study was based on laboratory tests evaluating the efficacy in eliminating three different <i>C. difficile</i> strains on carriers made of plastic, metal and glass after 10 min exposure to UV-C (wavelength, 253.7 nm). We observed a wide range of reductions in the <i>C. difficile</i> suspensions depending on the density of the carrier contamination, type of carrier, strains and the location of the carrier. The percentage reductions ranged from 0 to 100%, but the best results were observed for glass, with lower initial suspension density and carrier placement on a door frame. Statistically significant differences were only seen in different suspension densities. Our experiment was a continuation of the tests done for non-sporing bacteria and <i>C. auris</i>, and there were some interesting differences in <i>C. difficile</i> reflecting its biology, especially its sensitivity to an aerobic atmosphere during the sample drying. Although the elimination of <i>C. difficile</i> by UV-C radiation was confirmed in our experiment, it was lower than in the case of non-spore-forming bacteria. Thus, this method may be used in healthcare settings (hospitals) for improving environmental safety and preventing <i>C. difficile</i> spreading.