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Long-term antimicrobial effectiveness of a silver-impregnated foil on high-touch hospital surfaces in patient rooms

Antimicrobial Resistance & Infection Control volume 10, Article number: 120 (2021) Cite this article

Abstract

Background

The hospital environment has got more attention as evidence as source for bacterial transmission and subsequent hospital-acquired infection increased. Regular cleaning and disinfection have been proposed to lower the risk of infection, in particular for gram-positive bacteria. Auto-disinfecting surfaces would allow to decrease survival of pathogens, while limiting resource to achieve a safe environment in patient rooms.

Methods

A controlled trial to evaluate the antimicrobial effectiveness of a polyvinyl chloride foil containing an integrated silver-based agent (containing silver ions 2%) on high-touch surfaces in patient rooms.

Results

The overall log reduction of the mean values was 1.8 log10 CFU, the median 0.5 log10 CFU comparing bioburden of control vs antimicrobial foil (p < 0.01). Important pathogens were significantly less likely recovered from the foil, in particular enterococci. These effects were present even after 6 months of in-use.

Conclusions

A foil containing an integrated silver-based agent applied to high-touch surfaces effectively results in lower recovery of important pathogens from such surfaces over a 6-month study period.

Introduction

Healthcare-associated infections (HAIs) affect millions of patients every year challenging healthcare institutions [1]. In Europe, 6.5% of patients in acute care hospitals develop at least one HAI [2]. By effective infection control programs, 20–30% of HAIs are considered to be preventable. Goals to decrease HAIs have been met in the last decade, but a large burden for patients remains still requiring more efforts for prevention [3]. Nosocomial pathogens causing HAIs originate from the patients’ endogenous flora in 40–60%, in 20–40% as results of cross-infection from contaminated hands of healthcare workers (HCW) and approximately 20% from contamination of the environment, depending on the pathogen [4]. Multidrug-resistant microorganisms as well as Clostridioides difficile are frequent causes of HAIs, in particular meticillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and Acinetobacter baumannii that are commonly involved in the transmission of these pathogens [5,6,7]. These microorganisms can persist on hospital surfaces from hours to months, depending on location, number, biofilm formation, intrinsic resistance of organisms to various cleaning products as well as local conditions [8]. For VRE, contact with a contaminated environment results in a similar risk of contamination of HCW hands, independent of contact with intact skin of a colonized patient or his environment [9]. Cleaning and disinfection may reduce HAIs [6, 7], as documented for C. difficile [10]. Routine contact isolation for patients with non-hypervirulent C. difficile can even be lifted, if standard precautions and cleaning of the environment are ensured [11, 12]. Enhanced cleaning and disinfection can even be cost-effective [13]. Pathogens can be transmitted by hands of HCW after patient care, but also from touching the environment close to patients [9]. Routine hand hygiene would eliminate this risk, but in reality, high compliance and appropriate technique remain an ongoing challenge [14]. Another approach is repetitive daily cleaning and disinfection of critical surfaces, but this is very costly, and can impede patient care. In addition, recolonization of the surfaces occurs within hours after cleaning [15, 16]. Even terminal cleaning after patient discharge cannot always kill pathogens left on surfaces by prior room occupants [17]. Therefore, continuous antimicrobial activity against microorganisms by auto-disinfecting materials or coating are current matter of research [18]. Copper has been successfully tested to prevent HAIs in hospitals, but it is very expensive, heavy and confirmation studies are pending [19]. A very recent clinical trial compared high-touch surfaces coated with a quaternary ammonium polymer with non-coated surfaces to determine the impact on the incidence of HAIs [20]. Similarly, this study tested a silver-impregnated foil mounted on high-touch surfaces in patient rooms, to evaluate the antimicrobial activity on bioburden and presence of important pathogens.

Materials and methods

Antimicrobial foil

The commercially available antimicrobial foil PURZON060B produced by HEXIS S.A. (Frontignan, France) was used for the study. The flexible, transparent and 60 µm thick polyvinyl chloride foil contains an integrated silver-based agent (containing 2% silver ions) developed and manufactured by SANITIZED AG (Burgdorf, Switzerland). Detailed specifications of the antimicrobial foil PURZON060B are provided at https://hexis-graphics.com/documents/fichestechnique/document_en/aut_PURZON060B_FTP_anglais.pdf.  Last access June 3, 2021.

Study setting

The prospective and comparative study was conducted in one surgical and one medical ward at the University Hospital Basel from March through May 2020. Based on a previous study [21], a reduction of > 50% of the bioburden or important pathogens was considered as clinically meaningful.

On each ward, high-touch surfaces in three patient rooms were coated with the antimicrobial foil. The following high touch surfaces were selected: overbed table, nightstand, armrest of a resting chair, dining table, toilet ring and toilet flusher. The corresponding control surfaces were defined on the same furniture, either adjacent or on the other side (e.g. left and right armrest). The right or left position of the foil or control surface was selected alternately. Since the toilet ring and the toilet flusher had to be fully covered with foil for technical reasons, the controls were taken from an adjacent patient room. Overall, 12 overbed tables, 12 nightstands, 8 armrests, 7 dining tables, 4 toilet rings and 4 toilet flushers were coated with antimicrobial foil, resulting in 47 coated test surfaces and 47 uncoated control surfaces. The self-adhesive antimicrobial foil was applied by trained technicians.

Sampling

Samples for microbiological investigations were collected every Monday and Wednesday after 5 pm with flocked swabs moistened with NaCl solution prior to use and after swabbing put in eSwab® transport medium (Copan, Brescia, Italy). Guided by clean 25.2 cm2 metal templates, the test foil as well as the control surfaces were swabbed. The swabs were immediately brought to the microbiology laboratory and stored at 4–8 °C overnight before processing.

Laboratory methods

Out of the eSwab® fluid, 250 µl were inoculated on each of the following culture media: trypticase soy agar, ChromID® CPS® Elite and ChromID® S. aureus Elite (bioMérieux, Marcy-l’Étoile, France). The media were incubated at 36° ± 1 °C for 42–48 h. Colony-forming units (CFU) were counted and suspected pathogenic isolates were identified with matrix-assisted laser desorption/ionization – time of flight (MALDI-TOF) mass spectrometry (MALDI Biotyper®, microflex™ LT/SH smart, Bruker Daltonik, Bremen, Germany). The microbiological analysis focused on the following important pathogens: S. aureus, Enterococcus faecalis, E. faecium, other Enterococcus spp., haemolytic streptococci, Enterobacterales, Pseudomonas spp., and A. baumannii group.

Policy of cleaning and disinfection of the environment

All patient rooms are cleaned once daily with a detergent and single-use microfiber pads. Washrooms are routinely disinfected with Deconex® 50FF (Borer Chemie, Zuchwil, Switzerland), an aldehyde-free certified disinfectant based on ethanedial, pentanedial and didecyldimethylammonium chlorid.

Statistical analysis

Data was collected in a spreadsheet, imported into and analyzed with Python 3.7.7 (pandas 1.0.3, scipy 1.4.1, numpy 1.18.4). Culture results were reported as log10 CFU /cm2. The mean log10 reduction was calculated as difference between the log10 of the mean CFU of samples taken from the antimicrobial foil and the control surface. The median log10 reduction was calculated respectively. For the comparison between CFU on the antimicrobial foil versus the uncoated control surface, the values were compared by Wilcoxon signed rank test and for nonrelated samples by Mann Whitney U test. P values < 0.05 (two-sided) were considered statistically significant.

Results

Overall, 403 swabs were sampled: 201 from the antimicrobial foil, 202 from uncoated control surfaces. Cultures were negative in 79 samples: 53 (67%) from antimicrobial foil and 26 (33%) from control samples (p < 0.001). The overall log reduction of the mean values was 1.8 log10 CFU, the median 0.5 log10 CFU comparing bioburden of control versus antimicrobial foil (p < 0.01, Tables 1, 2). Higher reductions were observed in samples with high bioburden on control samples: The highest reduction was observed in toilet samples with 2.0 log10 CFU reduction (p < 0.01).

Table 1 Mean log10 reduction CFU overall and CFU of important pathogens on antimicrobial foil compared to control surfaces
Full size table
Table 2 Median log10 reduction CFU overall on antimicrobial foil compared to control surfaces
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More importantly, 49 different important pathogens were found on 38 samples: 9 (34%) from the antimicrobial foil, 29 (76%) from the control samples (p < 0.001). Over 90% of important pathogens were gram-positive bacteria, bacteria that survive well on dry surfaces. Large differences between the antimicrobial foil compared to the control surfaces were observed in detection of enterococci (Fig. 1). Acinetobacter spp. also belong to bacteria that can survive for prolonged periods of time: However, none of the samples were positive for Acinetobacter baumanii group. Very few gram-negative bacteria were isolated to make meaningful comparisons.

Fig. 1
figure 1

Presence of important pathogens

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The long-term effect over 6 months was confirmed by repeating samples from the antimicrobial foil (Table 3).

Table 3 CFU after 6 months of use in patient rooms
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Discussion

Multiple studies have confirmed the impact of proper removal of environmental pathogens on the incidence of transmission [6, 16, 22], even in randomized controlled clinical trials and it appears to be cost-effective [13]. One very recent study indicates that environmental control in hospitals leads to significantly lower rates of HAIs [20]. The importance of environmental contamination control has increased in healthcare institutions over time. It might be of higher importance to fight against transmission of multidrug-resistant microorganisms than for decreasing HAIs. In this study, bioburden was significantly reduced by the antimicrobial foil: measured as reduction in the mean CFU as well as the median, the latter commonly leading to a lower effect [20]. It also succeeded in significant decrease of important pathogens, in particular E. faecalis and E. faecium. Prior environmental contamination of hospital rooms may increase the risk of acquisition of enterococci [23] and was responsible for one of the largest country-wide epidemic with VRE in Switzerland [24]. The E. faecium clone ST 796 was likely introduced from Australia, spread to many Swiss hospitals and lasted more than two years despite intensified contact isolation, preemptive isolation, admission screening and even hospital wide screening of all patients. An effective disinfectant rapidly kills enterococci including VRE, but environmental recolonization occurs within hours after disinfection [15]. Therefore, an auto-disinfectant surface would be desirable in certain areas such as transplant units or also during pandemics as currently with SARS-CoV-2 [25], as bacterial communities seem to contribute to viral prevalence in the hospital environment [26]. The PURZON060B antimicrobial foil has been tested against human coronavirus HCoV-229E in vitro, and was highly active in-vitro (data from a certificate, https://catalogues.hexis-graphics.com/c/frxfr-hexis-pure-zone), supplementary appendix file 1). However, our study design was submitted in autumn 2019, and resources and biosafety limitations precluded testing the product in patient rooms.

The foil could be placed on different surfaces without getting loose over time. However, the removal of the foil needs special expertise, since it sticks very well to the surface. In addition to the impregnated foil, the silver-based antimicrobial compound has been successfully incorporated into a variety of other materials such as fabrics and synthetics to finish various surfaces and equipment making this compound of interest for further applications.

Several study limitations need to be considered: We took samples 8–10 h after routine cleaning and disinfection, after patients and HCW were using the environment as deemed necessary for the daily work and requirements. The frequency of touching surfaces was beyond control of the study, but the hospital policy requires daily cleaning and/or disinfection. However, the sampling technique was designed to take samples exactly from the adjacent area as the antimicrobial foil was put on. A long-term effect over years was not assessed to study longevity. Since during the study the pandemic with SARS-CoV-2 spread throughout Switzerland, the study had to be temporarily interrupted from mid-March to end of April. We continued the study to estimate the effect of massively increased disinfection policy. Due to the lower occupancy of the wards and restricted access of visitors, the bioburden on the study surfaces had significantly decreased to nearly undetectable levels (data not shown). Increased cleaning and disinfection to at least once daily, with emphasis to washrooms could be an effective alternative to the use of such an auto-disinfectant antimicrobial foil.

In conclusion, this polyvinyl chloride foil containing an integrated silver-based agent applied to high-touch surfaces effectively results in lower recovery of important pathogens from such surfaces, even six months after clinical use in patient rooms. Auto-disinfectant foils or similar antimicrobially equipped surfaces might help to prevent transmission—in particular—of gram-positive pathogens from the environment.

Availability of data and materials

Data are available as Excel file und python statistical software. The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

References

  1. Zimlichman E, Henderson D, Tamir O, Franz C, Song P, Yamin CK, et al. Health care-associated infections: a meta-analysis of costs and financial impact on the US health care system. JAMA Intern Med. 2013;173(22):2039–46. https://doi.org/10.1001/jamainternmed.2013.9763.

    Article  PubMed  Google Scholar 

  2. Suetens C, Latour K, Karki T, Ricchizzi E, Kinross P, Moro ML, et al. Prevalence of healthcare-associated infections, estimated incidence and composite antimicrobial resistance index in acute care hospitals and long-term care facilities: results from two European point prevalence surveys, 2016 to 2017. Euro Surveil. 2018;23(46):66.

    Article  Google Scholar 

  3. Magill SS, O’Leary E, Janelle SJ, Thompson DL, Dumyati G, Nadle J, et al. Changes in prevalence of health care-associated infections in U.S. hospitals. N Engl J Med. 2018;379(18):1732–44. https://doi.org/10.1056/NEJMoa1801550.

    Article  PubMed  PubMed Central  Google Scholar 

  4. Dancer SJ. Controlling hospital-acquired infection: focus on the role of the environment and new technologies for decontamination. Clin Microbiol Rev. 2014;27(4):665–90.

    Article  Google Scholar 

  5. Erb S, Frei R, Dangel M, Widmer AF. Multidrug-resistant organisms detected more than 48 hours after hospital admission are not necessarily hospital-acquired. Infect Control Hosp Epidemiol. 2017;38(1):18–23.

    Article  Google Scholar 

  6. Rutala WA, Kanamori H, Gergen MF, Knelson LP, Sickbert-Bennett EE, Chen LF, et al. Enhanced disinfection leads to reduction of microbial contamination and a decrease in patient colonization and infection. Infect Control Hosp Epidemiol. 2018;39(9):1118–21. https://doi.org/10.1017/ice.2018.165.

    Article  PubMed  Google Scholar 

  7. Weber DJ, Rutala WA, Miller MB, Huslage K, Sickbert-Bennett E. Role of hospital surfaces in the transmission of emerging health care-associated pathogens: norovirus, Clostridium difficile, and Acinetobacter species. Am J Infect Control. 2010;38(5 Suppl 1):S25-33.

    Article  Google Scholar 

  8. Otter JA, Yezli S, Salkeld JA, French GL. Evidence that contaminated surfaces contribute to the transmission of hospital pathogens and an overview of strategies to address contaminated surfaces in hospital settings. Am J Infect Control. 2013;41(5 Suppl):S6-11.

    Article  Google Scholar 

  9. Hayden MK, Blom DW, Lyle EA, Moore CG, Weinstein RA. Risk of hand or glove contamination after contact with patients colonized with vancomycin-resistant enterococcus or the colonized patients’ environment. Infect Control Hosp Epidemiol. 2008;29(2):149–54.

    Article  Google Scholar 

  10. Salgado CD, Sepkowitz KA, John JF, Cantey JR, Attaway HH, Freeman KD, et al. Copper surfaces reduce the rate of healthcare-acquired infections in the intensive care unit. Infect Control Hosp Epidemiol. 2013;34(5):479–86.

    Article  Google Scholar 

  11. Tschudin-Sutter S, Kuijper EJ, Durovic A, Vehreschild M, Barbut F, Eckert C, et al. Guidance document for prevention of Clostridium difficile infection in acute healthcare settings. Clin Microbiol Infect. 2018;24(10):1051–4.

    Article  CAS  Google Scholar 

  12. Widmer AF, Frei R, Erb S, Stranden A, Kuijper EJ, Knetsch CW, et al. Transmissibility of Clostridium difficile without contact isolation: results from a prospective observational study with 451 patients. Clin Infect Dis. 2017;64(4):393–400. https://doi.org/10.1093/cid/ciw758.

    Article  PubMed  Google Scholar 

  13. White NM, Barnett AG, Hall L, Mitchell BG, Farrington A, Halton K, et al. Cost-effectiveness of an environmental cleaning bundle for reducing healthcare-associated Infections. Clin Infect Dis. 2020;70(12):2461–8. https://doi.org/10.1093/cid/ciz717.

    Article  PubMed  Google Scholar 

  14. Tschudin-Sutter S, Sepulcri D, Dangel M, Ulrich A, Frei R, Widmer AF. Simplifying the world health organization protocol: 3 steps versus 6 steps for performance of hand hygiene in a cluster-randomized trial. Clin Infect Dis. 2019;69(4):614–20.

    Article  Google Scholar 

  15. Meinke R, Meyer B, Frei R, Passweg J, Widmer AF. Equal efficacy of glucoprotamin and an aldehyde product for environmental disinfection in a hematologic transplant unit: a prospective crossover trial. Infect Control Hosp Epidemiol. 2012;33(11):1077–80.

    Article  Google Scholar 

  16. Anderson DJ, Chen LF, Weber DJ, Moehring RW, Lewis SS, Triplett PF, et al. Enhanced terminal room disinfection and acquisition and infection caused by multidrug-resistant organisms and Clostridium difficile (the Benefits of Enhanced Terminal Room Disinfection study): a cluster-randomised, multicentre, crossover study. Lancet. 2017;389(10071):805–14. https://doi.org/10.1016/S0140-6736(16)31588-4.

    Article  PubMed  PubMed Central  Google Scholar 

  17. Mitchell BG, Dancer SJ, Anderson M, Dehn E. Risk of organism acquisition from prior room occupants: a systematic review and meta-analysis. J Hosp Infect. 2015;91(3):211–7.

    Article  CAS  Google Scholar 

  18. Schmidt MG, Salgado CD, Freeman KD, John JF, Cantey JR, Sharpe PA, et al. Antimicrobial surfaces to prevent healthcare-associated infections: a systematic review - a different view. J Hosp Infect. 2018;99(3):309–11. https://doi.org/10.1016/j.jhin.2018.02.007.

    Article  CAS  PubMed  Google Scholar 

  19. Muller MP, MacDougall C, Lim M. Antimicrobial surfaces to prevent healthcare-associated infections: a systematic review. J Hosp Infect. 2016;92(1):7–13. https://doi.org/10.1016/j.jhin.2015.09.008.

    Article  CAS  PubMed  Google Scholar 

  20. Ellingson KD, Pogreba-Brown K, Gerba CP, Elliott SP. Impact of a novel antimicrobial surface coating on health care-associated infections and environmental bioburden at 2 urban hospitals. Clin Infect Dis. 2020;71(8):1807–13. https://doi.org/10.1093/cid/ciz077.

    Article  PubMed  Google Scholar 

  21. Widmer FC, Frei R, Romanyuk A, Tschudin Sutter S, Widmer AF. Overall bioburden by total colony count does not predict the presence of pathogens with high clinical relevance in hospital and community environments. J Hosp Infect. 2019;101(2):240–4.

    Article  CAS  Google Scholar 

  22. Mitchell BG, Hall L, White N, Barnett AG, Halton K, Paterson DL, et al. An environmental cleaning bundle and health-care-associated infections in hospitals (REACH): a multicentre, randomised trial. Lancet Infect Dis. 2019;19(4):410–8. https://doi.org/10.1016/S473-3099(18)30714-X.

    Article  PubMed  Google Scholar 

  23. Drees M, Snydman DR, Schmid CH, Barefoot L, Hansjosten K, Vue PM, et al. Prior environmental contamination increases the risk of acquisition of vancomycin-resistant enterococci. Clin Infect Dis. 2008;46(5):678–85. https://doi.org/10.1086/527394.

    Article  CAS  PubMed  Google Scholar 

  24. Wassilew N, Seth-Smith HM, Rolli E, Fietze Y, Casanova C, Führer U, et al. Outbreak of vancomycin-resistant Enterococcus faecium clone ST796, Switzerland, December 2017 to April 2018. Euro Surveil. 2018;23(29):1800351. https://doi.org/10.2807/1560-7917.ES.2018.23.29.

    Article  Google Scholar 

  25. Zhou Y, Zeng Y, Chen C. Presence of SARS-CoV-2 RNA in isolation ward environment 28 days after exposure. Int J Infect Dis. 2020;97:258–9. https://doi.org/10.1016/j.ijid.2020.06.015.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  26. Marotz C, Belda-Ferre P, Ali F, Das P, Huang S, Cantrel K, et al. Microbial context predicts SARS-CoV-2 prevalence in patients and the hospital built environment. medRxiv. 2020;22:26.

    Google Scholar 

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Acknowledgements

None.

Funding

By Innosuisse, the Federal Swiss Innovation Promotion Agency (Grant # 38216.1 IP-LS) (https://www.innosuisse.ch/inno/en/home.html): The sponsor had no influence on design of the study and collection, analysis, and interpretation of data and in writing the manuscript A supervisor of Federal Swiss Innovation Promotion Agency reviewed the protocol before the study began.

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Author notes

  1. Sonja Kuster

    Present address: Spital Muri, 5630, Muri, Switzerland

Authors and Affiliations

  1. Division of Infectious Diseases and Hospital Epidemiology, University Hospital Basel, 4031, Basel, Switzerland

    Andreas F. Widmer, Sonja Kuster, Marc Dangel, Sammy Jäger & Reno Frei

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Contributions

Sonja Kuster performed the study, collected the data and did a first analysis of the data. Sammy Jaeger, MS completed the statistical analysis after data additional data cleaning. Reno Frei supervised the study, and was responsible for the microbiological methods, and Andreas Widmer was P.I. of the study, received the grant, and wrote with Reno Frei the paper. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Andreas F. Widmer.

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Andreas Widmer and Sonja Kuster have contributed equally to this study

Supplementary Information

Additional file 1.

Appendix 1 (data from a certificate, https://catalogues.hexis-graphics.com/c/frxfr-hexis-purezone), supplementary appendix file 1).

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Widmer, A.F., Kuster, S., Dangel, M. et al. Long-term antimicrobial effectiveness of a silver-impregnated foil on high-touch hospital surfaces in patient rooms. Antimicrob Resist Infect Control 10, 120 (2021). https://doi.org/10.1186/s13756-021-00956-1

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Keywords

Antimicrobial Resistance & Infection Control

ISSN: 2047-2994

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