Assessment of a novel antimicrobial surface disinfectant on inert surfaces in the intensive care unit environment using ATP-bioluminesence assay

Abstract

Cross-contamination from inanimate surfaces can play a significant role in intensive care unit (ICU)-acquired colonization and infection. This study assessed an innovative isopropyl alcohol/organofunctional silane solution (IOS) to reduce microbial contamination on inert surfaces in a medical ICU. Baseline adenosine triphosphate bioluminescence testing (ABT)-measurements (N = 200) were obtained on designated inert ICU surfaces followed by IOS treatment. At 1 and 6 weeks, selective surfaces were randomized to either IOS-treated or nontreated controls for comparison using ABT (N = 400) and RODAC colony counts (N = 400). An ABT value of ≤45 relative light units (RLU) was designated as "clean," whereas >45 was assessed as "dirty." Mean RLU baseline values ranged from 870.3 (computer keyboard) to 201.6 (bed table), and 97.5% of surfaces were assessed as "dirty." At 6 weeks, the mean RLU of surfaces treated with IOS ranged from 31.7 (physician workstation) to 51.5 (telephone handpiece), whereas values on comparative control surfaces were 717.3 and 643.7, respectively (P < .001). Some 95.5% of RODAC cultures from IOS-treated sites at 6 weeks were negative, whereas 90.5% of nontreated sites were culture-positive, yielding multiple isolates including multidrug-resistant gram-positive and gram-negative bacteria. IOS-treated surfaces recorded significantly lower RLU and RODAC colony counts compared with controls (P < .001). A single application of IOS resulted in a persistent antimicrobial activity on inert ICU surfaces over the 6-week study interval.