Keeping Environmental Surfaces Cleaner between Cleanings: A Non-Kill Surface Technology for Decreasing Bacterial Attachment, Survival Time and Transmission on Environmental Surfaces in the Healthcare Setting

Background: Environmental surfaces in the healthcare setting are potential vehicles for the spread of human pathogens. The Sharklet micro-pattern is a physical surface modification that inhibits bacterial attachment and colonization without the use of antimicrobial agents, offering a continuous method to reduce pathogen presence and transmission on hospital fomites (Figure 1).

Figure 1: The non-kill Sharklet micro-pattern is a surface modification that can be imprinted into a variety of materials, including silicone elastomer as depicted. Grooves are three microns deep and two microns wide.

Objective: The goal of this study was to assess in vitro the ability of micro-patterned surfaces to reduce bacterial attachment, colonization and transmission in an aerobic environment compared to un-patterned control surfaces.

Methods: Micro-patterned and control (smooth) surfaces were exposed to a single-species bacterial suspension for 30 minutes, followed by a saline rinse to remove non-adherent cells. Bacteria attached to each of the surfaces was quantified after the rinse step, as well as after one hour drying, three hours drying, and 24 hours drying. In addition, surface-to-finger transference of bacteria was quantified before and after rubbing sterilized, gloved fingertips 10 times on sample surfaces. Two enumeration methods were used; either contact plates for direct counts from the surfaces, or plating of a cell suspension made by sonication of the surfaces in saline media. Bacterial strains tested included Staphylococcus aureus (MRSA and MSSA), Enterococcus faecalis (VRE), Serratia marcescens, and Pseudomonas aeruginosa.

Results: Sharklet micro-patterned surfaces demonstrated significant reduction in bacterial attachment, with an average of 63% reduction in attachment for all bacterial species compared to the smooth control surfaces. Aerobic survival time of the attached population of bacteria was also reduced compared to smooth control surfaces, with average reductions of 79% after one hour, 78% after three hours, and 89% after 24 hours. Additionally, there was a significant reduction in surface-to-finger transference of S. aureus off the micro-patterned surface compared to smooth control surfaces, with only 16% of bacteria transferring off the micro-patterned surfaces compared to 67% transferring off smooth surfaces (p=0.042).

Conclusions: The Sharklet micro-patterned surface demonstrated reduced attachment when exposed to bacteria, reduced survival time of attached bacteria, and reduced surface-to-finger transference of attached bacteria. Sharklet micro-patterned surfaces introduce an environmentally-friendly approach to reduce the risk of transmission of human pathogens in the healthcare setting.