Effect of automated ultraviolet C–emitting device on decontamination of hospital rooms with and without real-time observation of terminal room disinfection

Abstract

We studied the effectiveness of an ultraviolet C (UV-C) emitter in clinical settings and compared it with observed terminal disinfection. We cultured 22 hospital discharge rooms at a tertiary care academic medical center. Phase 1 (unobserved terminal disinfection) included cultures of 11 high-touch environmental surfaces (HTSs) after terminal room disinfection (AD) and after the use of a UV-C-emitting device (AUV). Phase 2 (observed terminal disinfection) included cultures before terminal room disinfection (BD), AD, and AUV. Zero-inflated Poisson regression compared mean colony forming units (CFU) between the groups. Two-sample proportion tests identified significance of the observed differences in proportions of thoroughly cleaned HTSs (CFU < 5). Significant P value was determined using the Bonferroni corrected threshold of α = .05/12 = .004. We obtained 594 samples. Risk of overall contamination was 0.48 times lower in the AUV group than in the AD group (P < .001), with 1.04 log10 reduction. During phase 1, overall proportion of HTSs with <5 CFUs increased in AUV versus AD by 0.12 (P = .001). During phase 2, it increased in AD versus BD by 0.45 (P < .001), with no significant difference between AD and AUV (P = .02). Use of UV-C with standard cleaning significantly reduced microbial burden and improved the thoroughness of terminal disinfection. We found no further benefit to UV-C use if standard terminal disinfection was observed.