TY - CONF A1 - Schmidt, Selina A1 - Schreiber, Frank A1 - Boenke, Viola A1 - Nordholt, Niclas A1 - Kanaris, Orestis A1 - Sündermann, Claudia T1 - Bacterial resistance evolution towards disinfectants and antimicrobial surfaces and development of a standardized test N2 - Question Disinfectants and antimicrobial surfaces (AMCs) are important tools to prevent the spread of pathogens and antimicrobial resistant bacteria. However, concerns have been raised about the possibility for the evolution and selection of resistance against disinfectants and AMCs. In turn, resistance against disinfectants and AMCs can be associated to antibiotic resistance due to cross-resistance - a single mechanism conferring resistance to a disinfectant and an antibiotic- and co-resistance - two distinct mechanisms physically linked on e.g. a plasmid. The risk for resistance and cross-resistance during use of biocides (including disinfectants and AMCs) must be evaluated during authorization according to the EU biocidal product regulation. However, to date there is a lack of standardized methods that support risk assessment during the authorization process. Methods We used adaptive laboratory evolution (ALE) experiments which are based on repeated exposure of bacteria to disinfectants or AMCs. The experiments are followed by phenotypic (antimicrobial susceptibility testing) and genotypic (whole genome sequencing) characterization of the evolved strains. The basic idea of these experiments is to expose bacteria to lethal conditions and select for mutants with increased survival. This approach is fundamentally different to other ALE experiments, which commonly select for increased growth at subinhibitory concentrations. However, selection for increased survival represents a selective pressure that more realistically reflects selection under in-use conditions of disinfectants and AMCs. Results First, we studied adaptation of E. coli during repeated disinfection with benzalkonium chloride in a suspension assay. The experiments showed a 2000-fold increase in survival within 5 exposure cycles. The adaptive changes are linked to highly parallel mutations in genes related to lipid A biosynthesis, less negative cell surface charge, reduced growth rate and increased competitive ability in the presence of certain antibiotics. We use the same approach to develop standardizable ALE experiments based upon accepted standards that are used to determine the efficacy of disinfectants (EN 13697) and antimicrobial surfaces (ISO 22196). The results highlight pronounced adaptation of different test strains towards surface disinfection (benzalkonium chloride and isopropanol) and AMCs (copper). Conclusion Bacteria can adapt with increased survival towards lethal stress imposed by disinfectants and AMCs. The adaptive ability of bacteria to disinfectants and AMCs can be determined in a standardized manner. T2 - 74. Jahrestagung der Deutschen Gesellschaft für Hygiene und Mikrobiologie [DGHM] e. V. CY - Berlin, Germany DA - 05.09.2022 KW - Antimicrobial surfaces KW - ISO22196 KW - Antimicrobial resistance KW - Round robin test PY - 2022 AN - OPUS4-56432 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weiler, L. A1 - Pfingsten, J. A1 - Eickhoff, H. A1 - Geist, I. A1 - Hilbig, H. A1 - Hornig, U. A1 - Kalbe, Ute A1 - Krause, K. A1 - Kautetzky, D. A1 - Linnemann, V. A1 - Gschwendtner, M. A1 - Lohmann, D. A1 - Overeem-Bos, E. A1 - Schwerd, R. A1 - Vollpracht, A. T1 - Improving consistency at testing cementitious materials in the Dynamic Surface Leaching Test on the basis of the European technical specification CENTS 16637–2 – Results of a round robin test N2 - The environmental impact assessment of materials is usually based on laboratory tests, mostly in combination with models describing the longterm fate of the substances of interest in the targeted environmental compartment. Thus, laboratory tests are the fundamental link to achieve appropriate assessment conclusions which makes it essential to generate consistent results. This just as applies to the leaching of cementitious materials. In Europe, the leaching behavior of monolithic building materials is tested in the Dynamic Surface Leaching Test following the specification CEN/TS 16637–2. An interlaboratory comparison on European level regarding this technical specification showed relatively high intra- and interlaboratory variations for the tested materials (monolithic copper slag and cement stabilized coal fly ash). Therefore the German Committee for Structural Concrete (DAfStb) framed a guideline to specify additional testing conditions for cementitious materials. To assess the possible improvement by this guidelines measures, a round robin test with 11 participants from Germany and the Netherlands was conducted. This work aims to provide insight into the factors to be considered in the testing of alkaline materials, including sample preparation, and highlights crucial procedures and their manifestation in the results. All evaluated parameters showed improved results compared to the earlier round robin test. The relative standard deviations for repeatability (RSDr) and reproducibility (RSDR) of the elements calcium, barium, antimony, chromium, molybdenum and vanadium, which are the parameters evaluated in both round robin tests, were RSDr = 4%, 4%, 2%, 5%, 5%, and 5% respectively (4% in average) for this work, in comparison to the European round robin test with an average RSDr of 29% (17%, 17%, 20%, 40%, 36%, and 42%). The RSDR improved from 41% (30%, 36%, 29%, 57%, 40%, and 56%) to 14% (12%, 8%, 6%, 28%, 15%, and 12%). CO2 ingress during testing and the inaccuracy of eluate analytics for concentrations close to the determination limits were identified as the main sources of error. KW - Environmental assessment KW - Leaching KW - Heavy metals KW - Round robin test KW - Building Material PY - 2022 U6 - https://doi.org/10.1016/j.jenvman.2022.114959 SN - 0301-4797 VL - 314 SP - 1 EP - 9 PB - Elsevier CY - Amsterdam AN - OPUS4-54647 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - de Krom, I. A1 - Heikens, D. A1 - Richter, Matthias A1 - Horn, Wolfgang A1 - Baldan, A. T1 - CRMs for (semi-)VOCs in sorbent tubes N2 - EN 16516 sets the test method and requirements for the determination of emissions of Volatile Organic Compounds (VOCs) from building materials into indoor air. To address the quality control requirements for the class of semi-VOCs (SVOCs), VSL developed gaseous reference materials. A novel home-made dynamic gas mixture preparation system, operating according to ISO 6145-4 (continuous injection method), has recently been developed and validated. Thanks to the stable temperature control up to 100 oC, the system can prevent condensation of the SVOCs in air at indoor air concentration levels. The in-situ obtained SVOC gas standards can be sampled in sorbent tubes to obtain SVOC transfer standards. A study was performed to determine the optimal sorbent material and storage conditions. This study will be presented together with the results of the 2018 Round Robin test for emission test chamber measurements organised by BAM. Using the novel system, VSL prepared transfer standards with known amounts of VOCs and SVOCs for participants to evaluate their analytical performance. T2 - Emissions and Odours from Materials CY - Brussels, Belgium DA - 07.10.2019 KW - CRM KW - VOC transfer standards KW - Round robin test KW - Material emissions testing PY - 2019 AN - OPUS4-49423 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Horn, Wolfgang A1 - Richter, Matthias A1 - Wilke, Olaf T1 - Quality Improvement of VOC chamber emission tests observed for 10 years with round robin tests N2 - In Europe, the Construction Products Regulation (CPR, 2011/305/EU) sets basic requirements (BR) on how construction works must be designed and built. BR 3 “hygiene, health and the environment” states low emissions of toxic gases, Volatile Organic Compounds (VOCVOCs), particles, etc. from building materials. Meanwhile, a worldwide network of professional Commercial and non-commercial laboratories performing emission tests for the evaluation of products for interior use has been established. Therefore, comparability of test results must be ensured. The participation in Round Robin Tests (RRTRRTs) is a means to prove a laboratory’s proficiency. Since 2006 BAM offers such proficiency test for emission chamber test every two years. Any commercially available product on the market can be used as reference material, provided it is thoroughly characterised. However, these materials often emit only a few and material specific VOCs and appropriate homogeneity is not given. Therefore, alternative materials should be found. BAM used different materials over the years. Currently, the best suited reference material is a cured lacquer surface which contained several VOCs added to the liquid lacquer system. The round robin tests 2014, 2016 and 2018 were conducted with such a system. Compounds like Styrene or n-Alkanes like Decane or Tridecane were tested in many of the proficiency test operated by BAM. Up to now the relative standard deviation of these compounds decrease continuously. Starting with values about 30 % in 2008 we reached values for the mentioned compounds 15 to 20 % now. But even for more polar compounds improved results were received. Over the years the results of a large group of laboratories detected many compounds with much higher accuracy than at the beginning. So, the comparability between results of different laboratories becomes much better. T2 - International Conference on Risk Assessment of Indoor Air Chemicals CY - Berlin, Germany DA - 16.09.2018 KW - Chamber test KW - Round robin test KW - VOC-emission PY - 2018 AN - OPUS4-47906 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -