Effect of Automated Ultraviolet-C Emitting Device on Disinfection of Hospital Rooms With and Without Real-time Auditing of Cleaning Process

Background: Hospital environment has gained importance as one of the major factors in occurrence of hospital acquired infections (HAI). To our knowledge, only three studies have evaluated the effectiveness of automated ultraviolet-C (UV-C) emitters in eradicating micro-organisms in real hospital environments as opposed to experimental conditions. Most hospitals currently use visual assessment of a disinfected room rather than real-time auditing during disinfection. This is the first study to compare the difference of microbial counts after observed versus unobserved disinfection and after UV-C disinfection in either scenario. Vendor is unaware of the study and provided no assistance in any form including free product.

Methods: A prospective evaluation of hospital cleaning was conducted at a tertiary care academic medical center. Wilcoxon signed rank sum test was used to assess the differences between the aggregate numbers of bacterial colony forming units (CFU) per environmental site before and after use of the UV-C, before disinfection and after unobserved and observed disinfection of hospital rooms for 11 high touch surfaces (HTS). Z test was used to determine significance of proportion of HTS with <5 CFUs after unobserved vs observed disinfection.

Results: A total of 564 HTS cultures were obtained from 21 hospital rooms. 108 HTS were cultured before cleaning, 120 after unobserved disinfection, 108 after observed disinfection and 228 after timed exposure to UV-C. Use of an automated UV-C device led to significant decrease in total number of CFUs from 1,441 to 137 (1.02 log₁₀ reduction; P ≤ 0.05). The proportion of HTS with <5 CFUs after unobserved disinfection was 36% compared to 91% after observed disinfection (P = 0.008). Areas with >5 CFUs (mean ± SD) after UV cleaning and after observed disinfection were faucet (5.41 ± 25.1 CFU) and phone (9.1 ± 16.6 CFU) respectively.

Conclusion: Our data confirm that automated UV-C emitting devices can decrease the bioburden in hospital rooms in real life settings. More importantly, our study asserts the importance of conducting real-time audits in maximizing the benefit of hospital room disinfection and reducing bioburden than just visual assessments after disinfection process is completed.