Characterization of Microbial Community Present on Communal Surfaces with Antimicrobial Coatings

Abstract

Microbial contamination on high-touch communal surfaces poses a risk to human health. While traditional cleaning methods such as disinfection and washing are commonly used, they may be limited by human error, reduced microbial susceptibility, or the need for frequent reapplication. Antimicrobial coatings offer a promising alternative by providing persistent protection through mechanisms that inhibit microbial growth or attachment. Copper is one of the most frequently present materials in currently marketed antimicrobial coatings. The main aim of this study was to examine the bacterial communities on the handles of shopping baskets covered with metallic copper and to compare them with handles that had no copper surfaces. Microorganisms were collected from the handles using moistened cotton swabs, and the collected samples were used to count aerobically growing bacterial colonies. To eliminate the DNA of non-viable bacterial cells from community analysis, propidium monoazide dye (PMA), which is expected to bind the DNA of dead or heavily damaged bacteria, was added to part of the samples. Then, DNA was extracted from the samples, and sequencing libraries were constructed. The microbial communities on surfaces were identified through sequencing of the 16S rRNA variable region and analyzed using statistical tools. The results showed that basket handles coated with copper had significantly fewer aerobically growing bacterial colonies and lower species richness compared to the handles without copper surfaces. Additionally, the microbial taxa present on the surface differed from those found on uncoated handles. Treatment of the surface-collected microbial communities with PMA further influenced the composition of the microbiome. These findings suggest that copper-based antimicrobial coatings may reduce microbial burden and diversity on surfaces, and that PMA treatment is a valuable tool to use in experiments for differentiating between live and dead or significantly damaged microbes in DNA-based studies.