Antibacterial Coating for Pens as a Potential Pathogen Carrier, for General Hygiene

Antimicrobial Coating of Writing Pens as Potential Transmission Vectors for General Hygiene Inanimate surfaces can serve as passive vectors, facilitating the transfer of various microorganisms from surface to surface or surface to living organisms. Pens pose a risk as contamination sources for many individuals, particularly preschool and school-age children and hospital personnel, who represent the main at-risk groups. Coating the pen surface with a paint containing antimicrobial agents that does not exhibit cytotoxic or allergenic properties can reduce contamination by potential pathogenic microorganisms and associated infection risk. In our study, the antimicrobial effectiveness of a coating formulation containing the compound 3-(trimethoxysilyl)-propyl cocodimethylammonium chloride (Antimic®), which does not have cytotoxic or sensitizing effects, was evaluated by modifying the ISO 22196:2011 standard. Pens are instruments used daily and frequently by individuals from all age and professional groups. However, they are not properly cleaned before and after use. Healthcare personnel and visitors in shared offices, health professionals in hospitals, as well as preschool and school-age children frequently come into contact with uncleaned pens or those contaminated with microorganisms. As is known, microorganisms can survive on environmental surfaces and can be transferred to different objects and/or individuals through contact with these contaminated surfaces. The survival of microorganisms on inanimate surfaces depends on factors such as relative humidity, temperature, the material and roughness of the surface, the type of microorganism, whether viruses are enveloped or non-enveloped, and the microorganism's resistance to environmental stress conditions. For example, bacteria can be more numerous in porous and moist environments, while non-enveloped viruses such as Norovirus and Astrovirus are quite stable on environmental materials, surviving up to 60 days on dry non-porous surfaces and up to 90 days on porous surfaces [1]. On the other hand, although non-enveloped viruses are less stable, Influenza A virus survives on dry surfaces for up to 48 hours, and the enveloped SARS coronavirus survives for up to 96 hours [1]. In studies conducted with endemic human coronavirus strain (HCoV-) 229E, it was determined that the virus could remain infectious on different materials for 2 hours to 9 days [2]. Inanimate objects, referred to as fomites and accepted as passive vectors, capable of carrying infectious agents, have been shown in numerous studies to facilitate the transfer of microorganisms from hand to surface and from surface back to hand, including self-inoculation of the nose, eyes, or oral mucosa. It is known that pens can be potential vectors in the transmission of various pathogens [1, 3, 4]. During storage, production, and especially during use, hard surfaces with hand contact such as pens can be frequently colonized by Gram-positive bacteria including Staphylococcus aureus, S. hominis, S. epidermidis, S. haemolyticus, S. warneri; Micrococcus spp., Enterococcus spp.; Gram-negative bacteria including Escherichia coli, Salmonella spp., Pseudomonas spp., Klebsiella spp.; and fungi including Candida spp. [3, 4]. In preventing cross-contamination resulting from microorganism colonization, coating the risk source object with antimicrobial agents provides a sustainable solution [5]. On the other hand, the coating material selected must exhibit antimicrobial properties without demonstrating cytotoxicity or sensitizing effects. Additionally, microbiological analysis appropriate to the sample is a critical point in proper evaluation of the process, and evaluation using standard methods where available, or by modifying existing standard analysis methods and/or in-house test designs where not available, plays a key role.

2. Materials and Methods 2.1. Preparation of Antimicrobial Coating

The coating formulation must be formulated in a manner suitable for coating a surface. The surface and other substances used in the coating formulation must neither damage the product nor pose a health hazard to the user. In this respect, the antimicrobial active agent used in the coating should not react with other auxiliary substances present in the formulation. In the study, the antimicrobial coating formulation used in pen production contains an antimicrobial active agent, cellulose/acrylic-based resin, at least one pigment as a colorant, aromatic solvents, and additive materials. The antimicrobial active agent used must conform to the definition in Article 4, Section 25, Paragraph (a) of the "Biocidal Products Regulation," which states that "an active substance; viruses and fungi, including those that exert general or specific effects on or against harmful organisms, as well as a substance or microorganism that can," and must be a product licensed by the Ministry.

2.2 Microbiological Analysis

As the first stage of microbiological analysis, the microbial load of the paint samples prepared was examined. For this purpose, sterility testing was performed by sampling from the samples with sterile swabs and plating on Tryptic Soya Agar (TSA, Oxoid) for bacteria and Sabouraud Dextrose Agar (SDA, Oxoid) for mold and yeast counts. The antimicrobial activity of the paint samples was evaluated by modifying the ISO 22196:2011 standard. For this purpose, samples were spread on acetate film and dried. Immediately before analysis, samples were wiped with ethanol and dried, after which their antimicrobial effectiveness was evaluated. 400 μl of bacterial suspensions at 1x10⁵ CFU/ml were dripped onto dried plates, and the suspension was covered with sterile stretch film measuring 4x4 cm to ensure complete contact between the bacterial suspension and the sample. The stretch-covered painted plates were incubated at 37°C for 24 hours in an incubator with 90% relative humidity. After the contact period ended, samples were transferred to a neutralizing solution suitable for the bacterium and the antimicrobial compound used to stop the effectiveness of the antimicrobial agent. The neutralizing solution was serially diluted 1:10 in sterile phosphate buffer. 1 ml from all dilution tubes was plated on Plate Count Agar medium (PCA, Oxoid). After Petri dishes were incubated at 37°C for 24 hours, the resulting colonies were counted, the reduction in bacterial count in the test group compared to the control group was calculated, and the (R) value specified in the ISO 22196 standard was determined. Experiments were conducted in triplicate [6].

R (Antimicrobial Activity) = Ut - At

Ut: Number of culturable viable cells obtained from control pieces after 24 hours of contact time At: Number of culturable viable cells obtained from test pieces after 24 hours of contact time According to JIS, an R value of 2 or higher is considered "antimicrobial" [6].

3. Results

According to sterility testing of the prepared sample, it was determined that it did not carry bacterial and fungal load (Table 1). Table 1. Evaluation of the prepared paint sample in terms of sterility (CFU*/g). Table 2. Antimicrobial effectiveness of samples coated with paint containing Antimic® compound against S. aureus ATCC 6538 and E. coli ATCC 8739 strains according to ISO 22196 standard after 24 hours of contact time   Paint samples containing Antimic® demonstrated strong antimicrobial activity with ≥4 log (99.99%) reduction and R>2 value against S. aureus and E. coli bacteria during 24 hours of contact time (Table 2).

4. Discussion and Conclusion

Based on the results of the study, the use of antimicrobially effective paint can prevent cross-contamination and infections that may result from contact with the pen surface serving as a fomite and associated infections. The functional groups on the Antimic® compound used in our study do not undergo migration due to their reaction with the coating material and do not cause any toxicity during prolonged exposure. Paint containing Antimic®, with its non-toxic nature and strong antimicrobial effect, would serve the public interest by significantly reducing the risk of potential cross-contamination when used on pen surfaces.

References [1] Bright, K. R., Boone, S. A., & Gerba, C. P. (2010). Occurrence of bacteria and viruses on elementary classroom surfaces and the potential role of classroom hygiene in the spread of infectious diseases. The Journal of School Nursing, 26(1), 33-41. [2] Kampf, G., Todt, D., Pfaender, S., & Steinmann, E. (2020). Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents. Journal of hospital infection, 104(3), 246-251. [3] Halton, K., Arora, V., Singh, V., Ghantoji, S. S., Shah, D. N., & Garey, K. W. (2011). Bacterial colonization on writing pens touched by healthcare professionals and hospitalized patients with and without cleaning the pen with alcohol based hand sanitizing agent. Clinical Microbiology and Infection, 17(6), 868-869. [4] Cinar, N., Nemut, T., Dede, C., Altun, I., & Köse, D. (2014). Do the pens used by nursing students in clinics cause bacterial contamination? Iranian Journal of Nursing And Midwifery Research, 19(3), 331. [5] Bal, S. & Şanlı, N. Ö. (2020). İç mekân hijyen koşullarının arttırılmasında antibakteriyel duvar boyasının etkinliğinin değerlendirilmesi. Gazi Üniversitesi Mühendislik Mimarlık Fakültesi Dergisi, 35(4), 1913-1922. [6] ISO 22196:2011. Measurement of Antibacterial Activity on Plastics and Other Non-Porous Surfaces. https://www.iso.org/standard/54431.html. Publication Date August 2011. Access Date December 15, 2019.