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Comparative performance of a panel of commercially available antimicrobial nanocoatings in Europe.

Molling JW, Seezink JW, Teunissen BE, Muijrers-Chen I, Borm PJ - Nanotechnol Sci Appl (2014)

Bottom Line: The differences in antimicrobial activity among all of the coatings, expressed as log reduction values, varied between 1.3 and 6.6, while the variation within the nanomaterial-based group was between 2.0 and 6.2.Although nanosilver coatings were on average very effective in reducing the number of viable bacteria after challenge, the strongest log reduction (6.6) was seen with a coating that has immobilized, covalently bound quaternary ammonium salt in its matrix.However, considering the unknowns in relation to ecotoxicological emission and effects, it needs further consideration before widespread application into different environments.

View Article: PubMed Central - PubMed

Affiliation: Zuyd University of Applied Sciences, Heerlen, the Netherlands.

ABSTRACT

Background: Bacterial resistance against the classic antibiotics is posing an increasing challenge for the prevention and treatment of infections in health care environments. The introduction of antimicrobial nanocoatings with active ingredients provides alternative measures for active killing of microorganisms, through a preventive hygiene approach.

Purpose: The purpose of this study was to investigate the antimicrobial activity of a panel of antimicrobial coatings available on the European market.

Methods: A comparative, biased selection of commercially available antimicrobial coatings was tested for antimicrobial efficiency. Suppliers were contacted to deliver their coatings on glass and/or stainless steel substrates. In total, 23 coatings from eleven suppliers were received, which were investigated for their effect on the growth of Escherichia coli, using the International Organization for Standardization (ISO) 22196 protocol.

Results: The majority of nanomaterial-containing coatings (n=13) contained nanosilver (n=12), while only one had photocatalytic TiO2 as the active particle. The differences in antimicrobial activity among all of the coatings, expressed as log reduction values, varied between 1.3 and 6.6, while the variation within the nanomaterial-based group was between 2.0 and 6.2. Although nanosilver coatings were on average very effective in reducing the number of viable bacteria after challenge, the strongest log reduction (6.6) was seen with a coating that has immobilized, covalently bound quaternary ammonium salt in its matrix. Besides these two compounds, coatings containing TiO2, poly(dimethylsiloxane), triclosan, or zinc pyrithione evoked 100% killing of E. coli.

Conclusion: Our findings indicate that nanosilver dominates the nanoparticle-based coatings and performs adequately. However, considering the unknowns in relation to ecotoxicological emission and effects, it needs further consideration before widespread application into different environments.

No MeSH data available.


Related in: MedlinePlus

Study strategy to determine efficacy of different antimicrobial coatings.Notes: Antimicrobial activity was determined by the golden standard, the ISO 22196:2011 protocol, which comprises three major phases. In the first phase we challenged the antimicrobial coatings (AMC) and control surfaces with a suspension of Escherichia coli. Bacteria were recovered after 24 hours of incubation at 35°C. After 2 days of additional incubation using the pour plate method, the number of CFUs in the obtained suspensions was determined. The killing efficiency of the applied coatings was calculated as described in “Materials and methods”.Abbreviations: AMC, antimicrobial coating; CFU, colony-forming units; G, glass; ISO, International Organization for Standardization; SS, stainless steel.
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f1-nsa-7-097: Study strategy to determine efficacy of different antimicrobial coatings.Notes: Antimicrobial activity was determined by the golden standard, the ISO 22196:2011 protocol, which comprises three major phases. In the first phase we challenged the antimicrobial coatings (AMC) and control surfaces with a suspension of Escherichia coli. Bacteria were recovered after 24 hours of incubation at 35°C. After 2 days of additional incubation using the pour plate method, the number of CFUs in the obtained suspensions was determined. The killing efficiency of the applied coatings was calculated as described in “Materials and methods”.Abbreviations: AMC, antimicrobial coating; CFU, colony-forming units; G, glass; ISO, International Organization for Standardization; SS, stainless steel.

Mentions: An overview of the following method is depicted in Figure 1. Test strips containing antibacterial coatings and their corresponding stainless steel or glass control surfaces were tested in triplicate. Each test surface was quickly cleaned by slightly wiping with 70% EtOH prior to testing. After drying, the surfaces were challenged with E.coli (ATCC number 72002) according to the ISO 22196:2011 protocol, with minor adaptations. The protocol allows the use of other strains of E. coli then those suggested, but this should be mentioned by the researchers. This is the case in our work. Then, 400 µL bacterial suspensions (ca 105 CFU/mL) were added to the test and control surfaces, after which the samples were covered with a 40×40 mm plastic film. The bacterial suspension was incubated for 24 hours at 35°C (90% humidity). Next, bacteria were recovered in 10 mL soybean-casein-digest-lecithin-polysorbate 80 (SCDLP) medium and serially diluted. From each dilution, 1 mL was poured into Luria agar (LA) agar plates (nutrient agar mentioned in ISO 22196:2011 protocol) and incubated for 48 hours at 90% humidity, at 35°C. Obtained triplicates (not shown) were averaged, revealing: Ut and Ua (corresponding to control surface and coated surface, respectively, after incubation on LB agar plate). Ut and Ua were expressed as log values of the CFUs counted after bacterial challenge of the coated or noncoated substrates. The values were applied in the following algorithms:


Comparative performance of a panel of commercially available antimicrobial nanocoatings in Europe.

Molling JW, Seezink JW, Teunissen BE, Muijrers-Chen I, Borm PJ - Nanotechnol Sci Appl (2014)

Study strategy to determine efficacy of different antimicrobial coatings.Notes: Antimicrobial activity was determined by the golden standard, the ISO 22196:2011 protocol, which comprises three major phases. In the first phase we challenged the antimicrobial coatings (AMC) and control surfaces with a suspension of Escherichia coli. Bacteria were recovered after 24 hours of incubation at 35°C. After 2 days of additional incubation using the pour plate method, the number of CFUs in the obtained suspensions was determined. The killing efficiency of the applied coatings was calculated as described in “Materials and methods”.Abbreviations: AMC, antimicrobial coating; CFU, colony-forming units; G, glass; ISO, International Organization for Standardization; SS, stainless steel.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4230231&req=5

f1-nsa-7-097: Study strategy to determine efficacy of different antimicrobial coatings.Notes: Antimicrobial activity was determined by the golden standard, the ISO 22196:2011 protocol, which comprises three major phases. In the first phase we challenged the antimicrobial coatings (AMC) and control surfaces with a suspension of Escherichia coli. Bacteria were recovered after 24 hours of incubation at 35°C. After 2 days of additional incubation using the pour plate method, the number of CFUs in the obtained suspensions was determined. The killing efficiency of the applied coatings was calculated as described in “Materials and methods”.Abbreviations: AMC, antimicrobial coating; CFU, colony-forming units; G, glass; ISO, International Organization for Standardization; SS, stainless steel.
Mentions: An overview of the following method is depicted in Figure 1. Test strips containing antibacterial coatings and their corresponding stainless steel or glass control surfaces were tested in triplicate. Each test surface was quickly cleaned by slightly wiping with 70% EtOH prior to testing. After drying, the surfaces were challenged with E.coli (ATCC number 72002) according to the ISO 22196:2011 protocol, with minor adaptations. The protocol allows the use of other strains of E. coli then those suggested, but this should be mentioned by the researchers. This is the case in our work. Then, 400 µL bacterial suspensions (ca 105 CFU/mL) were added to the test and control surfaces, after which the samples were covered with a 40×40 mm plastic film. The bacterial suspension was incubated for 24 hours at 35°C (90% humidity). Next, bacteria were recovered in 10 mL soybean-casein-digest-lecithin-polysorbate 80 (SCDLP) medium and serially diluted. From each dilution, 1 mL was poured into Luria agar (LA) agar plates (nutrient agar mentioned in ISO 22196:2011 protocol) and incubated for 48 hours at 90% humidity, at 35°C. Obtained triplicates (not shown) were averaged, revealing: Ut and Ua (corresponding to control surface and coated surface, respectively, after incubation on LB agar plate). Ut and Ua were expressed as log values of the CFUs counted after bacterial challenge of the coated or noncoated substrates. The values were applied in the following algorithms:

Bottom Line: The differences in antimicrobial activity among all of the coatings, expressed as log reduction values, varied between 1.3 and 6.6, while the variation within the nanomaterial-based group was between 2.0 and 6.2.Although nanosilver coatings were on average very effective in reducing the number of viable bacteria after challenge, the strongest log reduction (6.6) was seen with a coating that has immobilized, covalently bound quaternary ammonium salt in its matrix.However, considering the unknowns in relation to ecotoxicological emission and effects, it needs further consideration before widespread application into different environments.

View Article: PubMed Central - PubMed

Affiliation: Zuyd University of Applied Sciences, Heerlen, the Netherlands.

ABSTRACT

Background: Bacterial resistance against the classic antibiotics is posing an increasing challenge for the prevention and treatment of infections in health care environments. The introduction of antimicrobial nanocoatings with active ingredients provides alternative measures for active killing of microorganisms, through a preventive hygiene approach.

Purpose: The purpose of this study was to investigate the antimicrobial activity of a panel of antimicrobial coatings available on the European market.

Methods: A comparative, biased selection of commercially available antimicrobial coatings was tested for antimicrobial efficiency. Suppliers were contacted to deliver their coatings on glass and/or stainless steel substrates. In total, 23 coatings from eleven suppliers were received, which were investigated for their effect on the growth of Escherichia coli, using the International Organization for Standardization (ISO) 22196 protocol.

Results: The majority of nanomaterial-containing coatings (n=13) contained nanosilver (n=12), while only one had photocatalytic TiO2 as the active particle. The differences in antimicrobial activity among all of the coatings, expressed as log reduction values, varied between 1.3 and 6.6, while the variation within the nanomaterial-based group was between 2.0 and 6.2. Although nanosilver coatings were on average very effective in reducing the number of viable bacteria after challenge, the strongest log reduction (6.6) was seen with a coating that has immobilized, covalently bound quaternary ammonium salt in its matrix. Besides these two compounds, coatings containing TiO2, poly(dimethylsiloxane), triclosan, or zinc pyrithione evoked 100% killing of E. coli.

Conclusion: Our findings indicate that nanosilver dominates the nanoparticle-based coatings and performs adequately. However, considering the unknowns in relation to ecotoxicological emission and effects, it needs further consideration before widespread application into different environments.

No MeSH data available.


Related in: MedlinePlus