TY - JOUR A1 - Cunliffe, A. J. A1 - Askew, P. D. A1 - Stephan, Ina A1 - Iredale, G. A1 - Cosemans, P. A1 - Simmons, L. M. A1 - Verran, J. A1 - Redfern, J. T1 - How do we determine the efficacy of an antibacterial surface? A review of standardised antibacterial material testing methods N2 - Materials that confer antimicrobial activity, be that by innate property, leaching of biocides or design features (e.g., non-adhesive materials) continue to gain popularity to combat the increasing and varied threats from microorganisms, e.g., replacing inert surfaces in hospitals with copper. To understand how efficacious these materials are at controlling microorganisms, data is usually collected via a standardised test method. However, standardised test methods vary, and often the characteristics and methodological choices can make it difficult to infer that any perceived antimicrobial activity demonstrated in the laboratory can be confidently assumed to an end-use setting. This review provides a critical analysis of standardised methodology used in academia and industry, and demonstrates how many key methodological choices (e.g., temperature, humidity/moisture, airflow, surface topography) may impact efficacy assessment, highlighting the need to carefully consider intended antimicrobial end-use of any product. KW - Antimicrobial materials KW - Antimicrobial testing KW - ISO 22196 KW - Antimicrobial surfaces KW - Antibacterial coatings PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-532138 SN - 2079-6382 VL - 10 IS - 9 SP - 1 EP - 14 PB - MDPI CY - Basel AN - OPUS4-53213 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Redfern, J. A1 - Tucker, J. A1 - Simmons, L. A1 - Askew, P. A1 - Verran, J. A1 - Stephan, Ina T1 - Environmental and experimental factors affecting efficacy testing on nonporous plastic antimicrobial surfaces N2 - Test methods for efficacy assessment of antimicrobial coatings are not modelled on a hospital environment, and instead use high humidity (>90%) high temperature (37 ◦C), and no airflow. Therefore, an inoculum will not dry, resulting in an antimicrobial surface exhibiting prolonged antimicrobial activity, as moisture is critical to activity. Liquids will dry quicker in a hospital ward, resulting in a reduced antimicrobial efficacy compared to the existing test, rendering the test results artificially favourable to the antimicrobial claim of the product. This study aimed to assess how hospital room environmental conditions can affect the drying time of an inoculum, and to use this data to inform test parameters for antimicrobial efficacy testing based on the hospital ward. The drying time of different droplet sizes, in a range of environmental conditions likely found in a hospital ward, were recorded (n = 630), and used to create a model to inform users of the experimental conditions required to provide a drying time similar to what can be expected in the hospital ward. Drying time data demonstrated significant (p < 0.05) variance when humidity, temperature, and airflow were assessed. A mathematical model was created to select environmental conditions for in vitro antimicrobial efficacy testing. Drying time in different environmental conditions demonstrates that experimental set-ups affect the amount of time an inoculum stays wet, which in turn may affect the efficacy of an antimicrobial surface. This should be an important consideration for hospitals and other potential users, whilst future tests predict efficacy in the intended end-use environment. KW - Method development KW - Standardisation KW - Antimicrobial test KW - Environmental conditions KW - Hospital premises PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-472699 SN - 2409-9279 VL - 1 IS - 4 SP - 36, 1 EP - 10 PB - MDPI CY - Internet open accsess AN - OPUS4-47269 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -