Lack of Association Between Surface Disinfection and Fluorescent Marker Score

BACKGROUND: The Centers for Disease Control and Prevention (CDC) recommend that hospitals ensure compliance with cleaning and disinfection procedures. Environmental Management Service (EMS) coordinators have used multiple methods to gauge effectiveness of cleaning activities. These methods include visual inspection, Adenosine Triphosphate (ATP) bioluminescence markers, fluorescent markers, and microbiological sampling. Although microbiological sampling is considered the “gold standard,” it is expensive and time consuming; therefore, alternative methods such as fluorescent markers are more commonly used. The purpose of this study was to determine whether fluorescent clean score was associated with a clean surface as determined by microbiological sampling. METHODS: The project was conducted at a 120-bed hospital within the Central Texas Veterans Healthcare System (CTVHCS). Rooms selected for inclusion were marked with a fluorescent marker in predetermined locations by a member of the research team. When the EMS staff person completed the routine cleaning process a member of the research team recorded the fluorescent score and obtained microbiological samples from the room. The aerobic bacterial colony (ABC) count for pre-cleaning and post-manual cleaning was also categorized into “clean” and “not-clean” categories, where clean was defined as ABC counts <2.5 CFU/cm(2). RESULTS: A chi-squared test of independence revealed that there was no association between surfaces considered “clean” according to ABC criteria and “clean” according to fluorescent marker score, chi-square = 1.6167, df = 1, P = 0.20. A mixed effects logistic regression model showed that fluorescent clean score was not a significant predictor of a clean surface as defined by the <2.5 CFU/cm(2) criteria (P = 0.96). CONCLUSION: While the fluorescent marker has been shown to be useful for determining if a surface has been wiped, our results show that fluorescent marker score may not be a good proxy for assessing surface disinfection. Our results suggest that fluorescent markers only determine if the manual process of wiping has been conducted without taking into account other variables that play a role in disinfecting the surface. DISCLOSURES: C. Jinadatha, Xenex healthcare Services: CRADA, Research support