Evaluation of antimicrobial properties in coatings for operating room surfaces

Abstract

Keywords: Acrylic; alkyd; antimicrobial properties; epoxy; infection control; operating room; polyurethane

1. Introduction

Creating and maintaining a sterile environment in an operating room (OR) is paramount for reducing the risk of infections and ensuring patient safety. Modern clean operating rooms must meet specific requirements for layout, floor, walls, and facilities, as well as selecting building materials and addressing hand washing room considerations [1]. The careful selection of building materials for the OR floor and walls plays a crucial role, with a focus on incorporating antimicrobial properties to enhance hygiene. Among the preferred materials for the OR floor, certain types of vinyl flooring are engineered with antimicrobial features, providing an easily cleanable and impermeable surface that resists

bacterial growth. Flooring, formulated with antimicrobial agents, contributes to a durable and hygienic surface, resistant to chemicals and easy to clean [2]. For the walls of the OR, antimicrobial paints with additives inhibiting bacterial and fungal growth are applied to enhance hygiene [2, 3]. Solid surface wall systems, such as non-porous and seamless wall panels, are chosen to prevent microbial growth, offering ease of maintenance. In the construction and maintenance ORs, the strategic application of various coatings, such as polyurethane, acrylic, alkyd, and epoxy, is essential to meet the specific demands of this critical healthcare environment. Polyurethane coatings, prized for their durability and chemical resistance, find utility in surfaces requiring robust protec-

*Corresponding author. *E-mail address: hcoza@pau.edu.tr Published by Yıldız Technical University Press, İstanbul, Türkiye This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).

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tion against chemicals and frequent cleaning, such as cabinets and medical equipment [4]. Acrylic coatings, known for their quick drying time and versatility, may be chosen for walls or ceilings in ORs where a fast-drying and easyto-apply solution is advantageous. With low odor and toxicity, acrylic coatings contribute to a cost-effective and aesthetically pleasing environment [5]. Alkyd coatings, being oil-based, are suitable for metal surfaces within the OR, offering reliable adhesion and protection against corrosion [6, 7]. They are commonly applied to metal components of furniture and medical devices. Epoxy coatings, renowned for exceptional durability and chemical resistance, are prevalent in ORs, particularly on floors and walls. The impermeable surface created by epoxy coatings resists chemicals, stains, and microbial growth, meeting the stringent hygiene requirements of operating rooms [8]. Each of these coatings plays a vital role in enhancing the functionality, durability, and cleanliness of different surfaces within the operating room, contributing to the overall safety and efficiency of healthcare practices. While not inherently possessing antimicrobial properties, these coatings can contribute significantly to creating a hygienic environment in ORs [9]. Some formulations of coatings can be enriched with antimicrobial agents like silver ions, imparting the surfaces with the ability to resist the growth of bacteria and fungi actively [10–12]. This is particularly advantageous when applied to surfaces requiring frequent cleaning. Establishing antimicrobial surfaces could be one of the keys to helping prevent further contagious incidents and breakouts. An antimicrobial surface must ensure that pathogenic contamination is eliminated or lowered to a minimum. Different antimicrobial agents are often added to coating formulas to prevent microbial growth. There are now various antimicrobial substrates on the market. It is worthwhile investigating the efficacy and precision of these products. Meanwhile, the use of antimicrobial agents is expanding, as is research into their antibacterial characteristics and components [11]. This study has designed an experiment to test the antimicrobial properties of polyurethane, acrylic, alkyd, and epoxy coatings. It has been investigated whether the bacteria will survive or proliferate, and if they don’t, how long will it take to be diminished on a surface coated with the substances. This study has been conducted on four types of coatings, observing 20 types of contaminant bacteria.

3. Results And Discussion

This study aimed to evaluate and determine the duration of the antimicrobial effect of different coatings that can be used operating rooms and hospitals. The data obtained from polyurethane and acrylic, coated panels at the end of 6 hours are shown in Table 3. The data obtained from alkyd, and epoxy coated panels at the end of 6 hours are shown in Table 4. Examining the antibacterial properties of polyurethane, acrylic, alkyd, and epoxy coatings reveals varying impacts on different bacterial strains. Polyurethane coating is most effective against Listeria monocytogenes 3b but less so against Proteus mirabilis. Acrylic coating significantly reduces Staphylococcus aureus counts, while Salmonella typhimurium shows the least response. Alkyd coating strongly affects Staphylococcus aureus but minimally impacts Methicillin resistant S.aureus. In the case of epoxy coating, Streptococcus epidermidis experiences the greatest reduction, while Salmonella typhimurium exhibits a less pronounced response. The coatings, ranked by their average percentage reduction in bacterial counts across all tested strains, exhibit varying levels of antibacterial efficacy. Acrylic coating leads with an impressive average reduction of 94.26%, followed closely by Alkyd and Epoxy coatings at 90.79% and 90.58%, respectively. In contrast, Polyurethane coating shows a somewhat lower average reduction at 74.79%. Based on the polyurethane ingredient list, it appears that the antibacterial properties of polyurethane coating may not be directly attributed to the listed components. The primary antibacterial effects might be due to the physical characteristics of the coating or other factors not explicitly mentioned in the provided ingredient list. The Acrylic ingredient list contains antimicrobial agents such as 1,2-benzisothiazol3(2H)-one (BIT), Zinc Pyrithione [13], and 2-octyl-2H-isothiazol-3-one (OIT). These components likely contribute to the observed antibacterial

Hydrocarbons, C9-C12, n-alkanes, isoalkanes, cyclics, aromatics (2−25%) ≥25−≤50 Titanium dioxide ≥10−≤25 Xylene ≤3 Hexanoic acid, 2-ethyl-, zinc salt, basic ≤0.3

Xylene ≥10−≤15 N-butyl acetate ≤10 Ethylbenzene ≤5 Titanium dioxide ≤5 Hydrocarbons, C9, aromatics ≤4.1 N-butyl methacrylate <1 2-Propenoic acid, 2-methyl-, 2- (dimethylamino)ethyl ester, polymer with butyl <1 2-propenoate, compd. with polyethylene glycol hydrogen maleate C9-11-alkyl ethers Decanedioic acid, 1,10-bis (1,2,2,6,6-pentamethyl-4-piperidinyl) ester, mixt. ≤0.3 with 1-methyl 10- (1,2,2,6,6-pentamethyl-4-piperidinyl) decanedioate Oleic acid, compound ≤0.1 Maleic anhydride ≤0.1

Table 1. Coatings ingredient used within the scope of the study. Acrylic-jotashield topcoat silk

Epoxy - Jotamastic 80 Epoxy resin (MW ≤700) Titanium dioxide Hydrocarbons, c9-unsatd., polymd Xylene 2-methylpropan-1-ol Benzyl alcohol Ethylbenzene Epoxy resin (MW 700−1200) 2-Propenoic acid, 2-methyl-, 2- (dimethylamino)ethyl ester, polymer with butyl 2-propenoate, compd. with polyethylene glycol hydrogen maleate C9-11-alkyl ethers Oleic acid, compound

Alcohols, C16-18 and C18-unsatd., ethoxylated 1,2-benzisothiazol-3(2h)-one (BIT) zinc pyrithione 2-octyl-2h-isothiazol-3-one (OIT)

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Table 2. Bacterial cultures used in antimicrobial analysis Microorganism E.coli E.coli O157 Bacillus subtilis Bacillus cereus Staphylococcus aureus Methicillin resistant S.aureus Vancomycin resistant Enterococcus faecium Streptococcus epidermidis Listeria monocytogenes 3b Salmonella enteritidis Salmonella typhimurium Campylobacter jejuni Geobacillus stearothemophilus Shigella flexneri Cronobacter sakazakii Pseudomonas aeruginosa Proteus mirabilis Acinetobacter baumanii Vibrio parahemolyticus Yersinia enterocolitica

Gram type Gram negative Gram negative Gram positive Gram positive Gram positive Gram positive Gram positive Gram positive Gram positive Gram negative Gram negative Gram negative Gram positive Gram negative Gram negative Gram negative Gram negative Gram negative Gram negative Gram negative

Figure 1. Polyurethane, acrylic, alkyd, and epoxy coated panels.

Table 3. Bacterial growth dynamics on polyurethane and acrylic surfaces over time

E.coli E.coli O157 Bacillus subtilis Bacillus cereus Staphylococcus aureus Methicillin resistant S.aureus Vancomycin resistant Enterococcus faecium Streptococcus epidermidis Listeria monocytogenes 3b Salmonella enteritidis Salmonella typhimurium Campylobacter jejuni Geobacillus stearothemophilus Shigella flexneri Cronobacter sakazakii Pseudomonas aeruginosa Proteus mirabilis Acinetobacter baumanii Vibrio parahemolyticus Yersinia enterocolitica

properties of the Acrylic coating. The concentrations mentioned suggest a careful formulation to provide effective antimicrobial action while minimizing potential adverse effects. BIT is a commonly utilized biocide applied to industrial products with broad antimicrobial activity [14, 15]. BIT has been shown to react with thiol-containing proteins on target microorganisms and is especially effective against actively metabolizing bacteria [16, 17]. It is widely used in food packaging, industrial and consumer products

like adhesives, laundry and dish detergents, cleaning and disinfectants, air fresheners, personal care products and sunscreens, paints, and industrial lubricants [18, 19]. OIT is a coordination complex of isothiazolone and has antibacterial and fungicidal properties [20]. It is used as a biocide in cooling-tower water, paints, cutting oils, cosmetics, and shampoos, and for leather preservation [20]. According to a CLH report published by the Chemicals Regulation Division United Kingdom, 2-octyl-2H-isothiazol-3-one ex-

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Table 4. Bacterial growth dynamics on alkyd and epoxy surfaces over time

E.coli E.coli O157 Bacillus subtilis Bacillus cereus Staphylococcus aureus Methicillin resistant S.aureus Vancomycin resistant Enterococcus faecium Streptococcus epidermidis Listeria monocytogenes 3b Salmonella enteritidis Salmonella typhimurium Campylobacter jejuni Geobacillus stearothemophilus Shigella flexneri Cronobacter sakazakii Pseudomonas aeruginosa Proteus mirabilis Acinetobacter baumanii Vibrio parahemolyticus Yersinia enterocolitica

hibited strong antibacterial activity against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa [21]. Alkyd coating is composed of a blend of hydrocarbons, titanium dioxide, xylene, and a zinc salt. Although hydrocarbons and titanium dioxide may not exhibit direct antibacterial properties, the inclusion of xylene [22] and the zinc salt [23, 24] suggests a potential contribution to the observed antibacterial effects. The overall performance of the coating is likely influenced by the specific formulation and interactions among these components. The epoxy coating contains a mix of components, including some with potential antimicrobial properties. However, the overall antibacterial efficacy is likely influenced by the combination and interactions of these components. Based on this information, none of these materials are inherently antibacterial and they all require proper care and maintenance to keep them hygienic. Some products may claim to have antibacterial features, but they may not be effective or long-lasting. Therefore, it is important to follow the manufacturer's instructions and use suitable cleaners for each material. A substantial proportion of antimicrobial coatings finds widespread use in the construction industry, particularly in the creation of both interior and exterior coatings designed to provide protection against microbial threats. There is a projected significant increase in the demand for antimicrobial coatings, especially in sectors such as hospitals, operating rooms, nursing homes, daycares, and other medical applications where maintaining a stringent standard of hygiene is imperative [11, 25]. In these crucial environments, the common practice involves integrating various antimicrobials into paint formulations to enhance the resilience of products against potential microbial attacks. Antimicrobial agents play a crucial role in

reducing the likelihood of microbial growth on coated surfaces, thereby ensuring a hygienic and sterile environment in medical settings [26–28]. While selecting these coatings, consideration of their compatibility with cleaning protocols, surface types, and adherence to healthcare regulations is crucial. Collaborating with infection control experts ensures that these coatings contribute effectively to the overall hygiene and safety standards of the operating room. Regular cleaning and disinfection practices further enhance the antimicrobial efficacy of these coatings, collectively fortifying the OR against potential infections.

4. Conclusion

This study investigated the pivotal role of antimicrobial coatings—polyurethane, acrylic, alkyd, and epoxy—in cultivating a hygienic environment within operating rooms and hospital settings. Applied strategically across diverse surfaces, these coatings significantly contributed to overall functionality, durability, and cleanliness, enhancing healthcare safety and efficiency. The experimental assessment of antimicrobial properties against 20 contaminant bacteria yielded noteworthy results. While the coatings may not inherently possess antimicrobial traits, formulations enriched with agents like BIT and OIT demonstrated active resistance against bacterial growth, emphasizing their potential in promoting hygiene. Results showed varying degrees of antimicrobial efficacy, with acrylic and epoxy coatings particularly excelling in inhibiting bacterial proliferation. The incorporation of antimicrobial agents notably enhanced the coatings ability to create surfaces resilient to microbial growth, highlighting their practical applications in critical healthcare settings like ORs.

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Ethics

There are no ethical issues with the publication of this manuscript.

Data Availability Statement

The authors confirm that the data that supports the findings of this study are available within the article. Raw data that support the finding of this study are available from the corresponding author, upon reasonable request.

Financial Disclosure

The authors declared that this study has received no financial support.

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