Terminal Decontamination of Patient Rooms Using an Automated Mobile UV Light Unit

• Published in: Infection control and hospital epidemiology 2011-08, Vol.32 (8), p.737-742
• Main Authors: Boyce, John M., Havill, Nancy L., Moore, Brent A.
• Format: Article
• Language: English
• Subjects: Antimicrobials; Bacteria, Aerobic - isolation & purification; Bathrooms; Biological and medical sciences; Chemical suspensions; Clostridium difficile - isolation & purification; Colony Count, Microbial; Decontamination; Disinfection - instrumentation; Disinfection - methods; Environmental disorders; Epidemiology. Vaccinations; Equipment and Supplies, Hospital - microbiology; General aspects; Infectious diseases; Medical sciences; Miscellaneous; Nursing; Original Article; Ozone; Patients' Rooms; Prospective Studies; Public health. Hygiene; Public health. Hygiene-occupational medicine; Rooms; Spores; Stainless steels; Toilets; Ultraviolet Rays
• ISSN: 0899-823X; 1559-6834
• DOI: 10.1086/661222

Objective.  To determine the ability of a mobile UV light unit to reduce bacterial contamination of environmental surfaces in patient rooms. Methods. An automated mobile UV light unit that emits UV-C light was placed in 25 patient rooms after patient discharge and operated using a 1- or 2-stage procedure. Aerobic colony counts were calculated for each of 5 standardized high-touch surfaces in the rooms before and after UV light decontamination (UVLD). Clostridium difficile spore log reductions achieved were determined using a modification of the ASTM (American Society for Testing and Materials) International E2197 quantitative disk carrier test method. In-room ozone concentrations during UVLD were measured. Results. For the 1-stage procedure, mean aerobic colony counts for the 5 high-touch surfaces ranged from 10.6 to 98.2 colony-forming units (CFUs) per Dey/Engley (D/E) plate before UVLD and from 0.3 to 24.0 CFUs per D/E plate after UVLD, with significant reductions for all 5 surfaces (all ). Surfaces in direct line of sight were significantly more likely to yield negative culture results after UVLD than before UVLD (all ). Mean C. difficile spore log reductions ranged from 1.8 to 2.9. UVLD cycle times ranged from 34.2 to 100.1 minutes. For the 2-stage procedure, mean aerobic colony counts ranged from 10.0 to 89.2 CFUs per D/E plate before UVLD and were 0 CFUs per D/E plate after UVLD, with significant reductions for all 5 high-touch surfaces. UVLD cycle times ranged from 72.1 to 146.3 minutes. In-room ozone concentrations during UVLD ranged from undetectable to 0.012 ppm. Conclusions. The mobile UV-C light unit significantly reduced aerobic colony counts and C. difficile spores on contaminated surfaces in patient rooms.