In vitro and in situ analysis of novel copper-based antimicrobial surface coatings designed to reduce the microbial bioburden of high-touch surfaces in a hospital environment

Background: The hospital environment plays a crucial role in healthcare-associated infections. Current cleaning protocols to address this are costly and labour intensive, with further complications related to compliance, efficiency and the environmental impact of cleaning agents. 

Findings: We developed a nano-structured coating, iC-nano™, which exhibits high antimicrobial activity. The 73 unique formulations assessed showed a range of activity in vitro. The best coatings displayed high activity within 15 min and were equally effective against all ESKAPE(e) pathogens except Enterococcus faecium, which required an increased contact time. Analysis within an active hospital environment identified 44% fewer colony-forming units (cfu) recovered from coated surfaces, though with some uncertainty in estimates of effect size (1.77 fold [95% credible interval {CrI}: 0.98, 3.13]). The highest counts were observed among toilet exits, whilst samples collected on a Wednesday had 45% less cfu than on Monday (0.55 fold [95% CrI: 0.32, 0.91]). Whilst the durability and antimicrobial activity of the coating remained stable, a key concern raised was the aesthetic of the product that gave the appearance of being soiled after sustained use, potentially leading to behaviour change. 

Conclusions: Through this study, we highlighted the promising potential of antimicrobial surfaces coatings. We suggest that future interventions, be they enhanced cleaning protocols or specialised coatings, should initially focus on locations such as toilet door handles, where the largest recoverable microbial bioburden was observed. Conversely, patient check-in screens saw minimal human interaction and are therefore considered a lower priority.