Effectiveness of surface coatings containing silver ions in bacterial decontamination in a recovery unit

BACKGROUND: HAIs remain a frequent complication for hospitalised patients and pose a challenge that must be tackled by our health systems. METHODS: Quasi-experimental study. In order to determine the antimicrobial effectiveness of surface coating agents containing silver ions (BactiBlock®) the degree of contamination of several surfaces in two ICU wards was compared. The association between application of Bactiblock® and surface contamination was analysed using a relative risk (RR). Multivariate logistic regressions were performed for each product applied and each sampling location to adjust for the RR of the contamination of surfaces treated with Bactiblock® for the independent variables. RESULTS: Surface contamination was observed in 31.5% of treated samples and 27.4 of untreated samples. Contamination was equally prominent on bedside Tables (38.7%), bed rails (38.4%) and sinks (38.3%), while the walls showed minimum contamination (2.6%). For beds under isolation protocols, contamination was higher (32.6%) than when no protocol was followed (26.5%) but the difference was not significant (p = 0.148). After stratification for application method and adjusting the multivariate models for period of the study and presence of isolated patients, the risk of contamination after the intervention increased when the coating agent was applied using a spray (OR = 1.79; 95% CI: 1.08-2.95, particularly in a dry and rugged surface such as that of bedside Tables (OR = 2.59; 95% CI: 1.22-5.52); and decreased when the product was applied using a roller on a smooth and continuously cleaned (or wet) Surface (OR = 0.42; 95% CI: 0.19-0.92). CONCLUSION: Coating of hospital surfaces with substances containing silver ions may reduce bacterial growth. However, the effectiveness of the coating agent is affected by application method and environmental conditions and the type and cleanness of the surface.