1215. Ultraviolet-C (UV-C) Monitoring Made Ridiculously Simple: UV-C Dose Indicators for Convenient Measurement of UV-C Dosing

BACKGROUND: Ultraviolet-C (UV-C) light is increasingly used as an adjunct to standard cleaning in healthcare facilities. However, most facilities do not have a means to measure UV-C to determine whether effective doses are being delivered. We tested the efficacy of 2 easy-to-use colorimetric indicators for monitoring UV-C dosing in comparison to log reductions in pathogens. METHODS: In a laboratory setting, we exposed methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile spores on steel disk carriers with or without an organic load (5% fetal calf serum) to UV-C for varying times resulting in fluence exposures ranging from 10,000 to 100,000 µJ/cm(2). The UV-C indicators were placed adjacent to the carriers. Log reductions were calculated in comparison to untreated controls and the change in color of the indicators was correlated with dose and log reductions. RESULTS: The UV-C doses required to achieve a 3-log reduction in MRSA and C. difficile were 10,000 and 46,000 µJ/cm(2), respectively. For both indicators, there was a visible color change from baseline at 10,000 µJ/cm(2) and a definite final color change by 46,000 µJ/cm(2) (Figure 1). Organic load had only a modest impact on UV-C efficacy. The indicators required only a few seconds to place and were easy to read (Figure 2). CONCLUSION: UV-C doses of 10,000 and 46,000 µJ/cm(2) were required to achieve 3 log reductions of MRSA and C. difficile spores, respectively. The colorimetric indicators provide an easy means to monitor UV-C dosing. [Image: see text] [Image: see text] DISCLOSURES: All authors: No reported disclosures.