Validação de torre de radiação UV-C contra microrganismos multidroga-resistentes para desinfecção de ambientes hospitalares.

Abstract

Healthcare-Associated Infections (HAIs) increase morbidity and costs, and the hospital environment is a reservoir of potentially pathogenic microorganisms. Traditional disinfection is prone to failure, and in this context, irradiation with ultraviolet light (UV-C) emerges as an effective and promising adjuvant technology. The general objective of this study was to validate the effectiveness of the automated portable UV-C radiation tower in disinfecting environments in health services against multidrug-resistant (MDR) microorganisms. Manuscript 1: Sought to evaluate the effectiveness of the low-cost UV-C light tower, determining its operational characteristics and the impact of its use as an adjuvant method in the disinfection of operating rooms for the control of MDR microorganisms. The study was conducted in two complementary phases. The first phase, in vitro, used strains of MDR microorganisms to optimize the distance and exposure time parameters of the UV-C device. The second phase, in situ, was a quasi-experimental study carried out in operating rooms of a large hospital. In it, complementary disinfection with the UV-C tower was compared to conventional cleaning and disinfection on high-touch surfaces, using artificially inoculated MDR microorganism strains. Efficacy was measured by the percentage and logarithmic reduction of the microbial load, and the statistical analysis using the Willcoxon test compared the results of the methods. In vitro tests demonstrated that the device was highly effective, achieving logarithmic reductions of up to 6.17 log₁₀ for most strains, with Candida auris requiring the longest exposure time. In the application in operating rooms, complementary disinfection with UV-C resulted in a statistically significant microbial reduction (p=0.0078) compared to conventional cleaning alone. On surfaces where standard cleaning was less effective, UV-C increased the reduction to 100%. By demonstrating the effectiveness of an affordable solution, the study offers an important strategy for infection control, especially because of the possibility of an affordable cost for the health system, where resources are limited. Manuscript 2: The objective of this study was to evaluate the usability of the UV-C Tower equipment, after the handling of the device by health professionals in the process of terminal disinfection of operating rooms. This was a cross-sectional and exploratory study conducted in a teaching hospital in Rio Grande do Sul, Brazil, between August and September 2025. The UV=C light disinfection device was operated by nurses trained in routine terminal cleaning of operating rooms. Usability was assessed using the System Usability Scale and Standardized User Experience Percentile Rank Questionnaire, applied to six professionals. The data were analyzed by measures of central tendency and dispersion. The average score of the equipment in the perception of users was 79.58% on the System Usability Scale, indicating usability classified as good. In the Standardized User Experience Percentile Rank-Questionnaire, the overall score was 81.47%, with emphasis on the dimension of trust (87.50%) and loyalty (79.16%). The results demonstrate a high perception of usability. The high score in dimensions such as ease of learning and trust suggest that the device has a fast learning curve and is well accepted by operators, important factors to ensure adherence to protocols and the correct application of the technology. Studies show that the UV-C light tower is effective and well accepted for the disinfection of operating rooms, acting as an adjuvant method to conventional cleaning in the control of MDR microorganisms. The combination of high microbiological efficacy and good usability indicates its potential to strengthen HAI prevention and control strategies, especially in resource-limited contexts.