Sorting through the wealth of options: comparative evaluation of two ultraviolet disinfection systems

• Published in: PloS one Vol. 9; no. 9; p. e107444
• Main Authors: Nerandzic, Michelle M, Fisher, Christopher W, Donskey, Curtis J
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 23.09.2014; Public Library of Science (PLoS)
• Subjects: Automation; Bacillus; Bacillus subtilis; Cleaning; Clostridium difficile; Clostridium difficile - radiation effects; Comparative analysis; Devices; Disinfection; Disinfection - instrumentation; Disinfection - methods; Dose-Response Relationship, Radiation; Drug resistance; Effectiveness; Enterococcus; Health care; Health facilities; Infection control; Irradiation; Light; Medicine and Health Sciences; Methicillin-Resistant Staphylococcus aureus - radiation effects; Organic loading; Ostomy; Pathogens; Sensors; Species Specificity; Spores; Staphylococcus infections; Stokes, Louis; Time Factors; Ultraviolet radiation; Ultraviolet Rays; Vancomycin-Resistant Enterococci - radiation effects; Veterans; Cleveland Ohio; United States > US; Ohio
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0107444

Environmental surfaces play an important role in the transmission of healthcare-associated pathogens. Because environmental cleaning is often suboptimal, there is a growing demand for safe, rapid, and automated disinfection technologies, which has lead to a wealth of novel disinfection options available on the market. Specifically, automated ultraviolet-C (UV-C) devices have grown in number due to the documented efficacy of UV-C for reducing healthcare-acquired pathogens in hospital rooms. Here, we assessed and compared the impact of pathogen concentration, organic load, distance, and radiant dose on the killing efficacy of two analogous UV-C devices. The devices performed equivalently for each impact factor assessed. Irradiation delivered for 41 minutes at 4 feet from the devices consistently reduced C. difficile spores by ∼ 3 log10CFU/cm2, MRSA by>4 log10CFU/cm2, and VRE by >5 log10CFU/cm2. Pathogen concentration did not significantly impact the killing efficacy of the devices. However, both a light and heavy organic load had a significant negative impacted on the killing efficacy of the devices. Additionally, increasing the distance to 10 feet from the devices reduced the killing efficacy to ≤3 log10CFU/cm2 for MRSA and VRE and <2 log10CFU/cm2 for C.difficile spores. Delivery of reduced timed doses of irradiation particularly impacted the ability of the devices to kill C. difficile spores. MRSA and VRE were reduced by >3 log10CFU/cm2 after only 10 minutes of irradiation, while C. difficile spores required 40 minutes of irradiation to achieve a similar reduction. The UV-C devices were equally effective for killing C. difficile spores, MRSA, and VRE. While neither device would be recommended as a stand-alone disinfection procedure, either device would be a useful adjunctive measure to routine cleaning in healthcare facilities.