TY - CONF A1 - Weimann, Karin T1 - Einführung in die Mantelverordnung - Stand der Bundes-Bodenschutz- und Altlastenverordnung N2 - Einführung in die Mantelverordnung Stand der Bundes-Bodenschutz- und Altlastenverordnung, aktuelles zum Aufbau der MVO und zum Stand Anfang 2023 T2 - X. Baustoffseminar - Aktuelles zu Gesteinskörnungen CY - Bad Berka, Germany DA - 17.01.2023 KW - Mantelverordnung KW - Gesteinskörnungen KW - Wiederverwertung PY - 2023 AN - OPUS4-57798 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weimann, Karin T1 - Entwicklungen im Gipsrecycling N2 - Gips gehört zu den nachgefragtesten Baustoffen und entsprechend steigt der Gipsverbrauch weltweit schon seit Jahrzehnten an. In Deutschland wird der Gipsbedarf seit vielen Jahren zu einem guten Teil durch REA-Gips, einem Nebenprodukt aus der Abgasreinigung von Kohlekraftwerken, gedeckt. Die weitere Gipsversorgung erfolgt größtenteils durch die Nutzung natürlicher Gipsvorkommen. Ein geringer, aber steigender Anteil an RC-Gips aus dem Baustoffrecycling und die Nutzung synthetischer Gipse aus Nebenprodukten anderer Industriezweige sind ebenfalls zu verzeichnen. Aufgrund der nationalen Klimaschutzziele und der damit verbundenen Abschaltung von Kohlekraftwerken wird das REA-Gipsangebot in den nächsten Jahren jedoch weiter deutlich zurückgehen, so dass andere Gipsquellen erschlossen werden müssen. Abhängig von der Lebensdauer der verwendeten Gipsprodukte im Bausektor ist infolge des in den vergangenen Jahren erfolgten Anstiegs des Gipsverbrauchs auch mit einer Zunahme von Gipsresten in Bau- und Abbruchabfällen zu rechnen. Im Hinblick auf eine bevorstehende Verknappung von Gips wird die Rückgewinnung dieser Gipse aus Bau- und Abbruchabfällen immer wichtiger. Das Recycling von Gipskartonplatten ist mittlerweile eine etablierte Technik und wird bereits seit einigen Jahren in industriellem Maßstab durchgeführt. Außerdem werden neue Verfahren zur Wiederverwertung weiterer Gipsprodukte aus Rück- und Umbaumaßnahmen untersucht. Von besonderem Interesse sind verschiedene Arten von Gipsplatten, da sie gut für selektiven Rückbau geeignet sind. Daher können sie vergleichsweise frei von Verunreinigungen oder Störstoffen zurückgewonnen werden, was für das Gipsrecycling besonders wichtig ist. In dem vom Bundesministerium für Bildung und Forschung geförderten Forschungsprojekt "GipsRec 2.0" werden technische, wirtschaftliche und ökologische Aspekte des Recyclings von Gipsfaserplatten sowie von verschiedenen Synthesegipsen untersucht und bewertet. Die Aufbereitung von Gipsfaserplatten erfolgte im halbtechnischen Maßstab, an verschiedenen potentiellen Ausgangsstoffen für synthetische Gipse wurden Laborversuche durchgeführt. Erfolgversprechende Verfahrenswege werden ökobilanziell bewertet. Ziel dieser Arbeiten ist die Erschließung der Sekundärrohstoffpotenziale von weiteren Quellen für die RC-Gipsproduktion um mit einer Steigerung des Gipsrecyclings die in naher Zukunft durch die Reduktion der REA-Gips-Bereitstellung entstehende Lücke in der Rohstoffversorgung zu verringern. T2 - 21. ibausil 2023 CY - Weimar, Germany DA - 13.09.2023 KW - Baustoffrecycling KW - Sekundärgipse KW - Ökobilanz PY - 2023 AN - OPUS4-60314 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stawski, Tomasz T1 - Solution-driven processing of calcium sulfate: the mechanism of the reversible transformation of gypsum to bassanite in brines N2 - Calcium sulfate hemihydrate (CaSO4ᐧ0.5H2O), also known as bassanite, has been used as a precursor to produce gypsum (dihydrate, CaSO4ᐧ2H2O) for various construction and decorative purposes since prehistoric times. The main route to obtain hemihydrate is a thermal treatment of gypsum at temperatures typically between 150 °C and 200 °C to remove some of the structural water. In this contribution, we introduce (Fig. 1) a more efficient and sustainable method (T < 100 °C) that enables the direct, rapid, and reversibly conversion of gypsum to bassanite using reusable high salinity aqueous solutions (brines with c[NaCl] > 4 M). The optimum conditions for the efficientproduction of bassanite in a short time (< 5 min) involve the use of brines with c(NaCl) > 4 M and maintaining a temperature, T > 80 °C. When the solution containing bassanite crystals is cooled down to around room temperature, eventually gypsum is formed. When the temperature is raised again to T > 80 °C, bassanite is rapidly re-precipitated. This contrasts with the typical behaviour of the bassanite phase in low salt environments. Traditionally, hemihydrate is obtained through a solid state thermal treatment because bassanite is considered to be metastable with respect to gypsum and anhydrite in aqueous solutions, and therefore gypsum-to-bassanite conversion should not occur in water. Its very occurrence actually contradicts numerical thermodynamic predictions regarding solubility of calcium sulfate phases. By following the evolution of crystalline phases with in situ and time-resolved X-ray diffraction/scattering and Raman spectroscopy, we demonstrated that the phase stability in brines at elevated temperatures is inaccurately represented in the thermodynamic databases. Most notably for c(NaCl) > 4 M, and T > 80 °C gypsum becomes readily more soluble than bassanite, which induces the direct precipitation of the latter from gypsum. The fact that these transformations are controlled by the solution provides extensive opportunities for precise manipulation of crystal formation. Our experiments confirmed that bassanite remained the sole crystalline structure for many hours before reverting into gypsum. This property is extremely advantageous for practical processing and efficient crystal extraction in industrial scenarios. T2 - Granada Münster Discussion Meeting GMDM 10 CY - Münster, Germany DA - 29.11.2023 KW - Gypsum KW - Bassanite KW - Calcium sulfate KW - Recycling KW - Scattering PY - 2024 AN - OPUS4-59162 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weimann, Karin T1 - Neue Ansätze beim Gipsrecycling N2 - Gypsum is widely used in the construction sector, and its worldwide consumption has been increasing now for several decades. Currently, the gypsum demand is met up to 60% by FGD gypsum (a by-product from coal-fired power plants) in Germany. The natural gypsum deposits cover the remaining gypsum demand. Due to national climate protection goals and the related shutdown of coal-fired power plants, the FGD gypsum supply will decrease significantly in the coming years and, therefore, other gypsum sources must be found. Depending on the lifetime of the used gypsum products in the construction sector, an increase of gypsum in construction and demolition waste is to be expected. With regard to an upcoming shortage of gypsum, several approaches are being tested to recover gypsum from construction and demolition waste. Gypsum plasterboard recycling is already implemented on an industrial scale. Furthermore, new processes to recycle different types of gypsum products from construction and demolition waste are being examined. Of particular interest are different types of gypsum boards because they are well suited for selective dismantling. Therefore, they can be recovered comparatively free of impurities which is most important for the gypsum recycling. In the research project “GipsRec 2.0”, funded by the Federal Ministry of Education and Research, recycling methods for gypsum fiberboards are being investigated. Additionally, the suitability of different types of synthetic gypsum as substitutes for FGD gypsum is being considered. Currently, the quantities of recycled gypsum are not sufficient with regard to the reduction of FGD gypsum. An increase of gypsum recycling should be achieved to narrow the future gypsum gap that will occur in the near future. T2 - Berliner Konferenz Mineralische Nebenprodukte und Abfälle CY - Berlin, Germany DA - 13.09.2021 KW - Gipsabfälle KW - Gipsrecycling KW - Nachhaltigkeit PY - 2021 AN - OPUS4-53682 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weimann, Karin T1 - Baustoffrecycling: Kreislaufwirtschaft und Umweltschutz N2 - Aktuelle Zahlen zum Baustoffrecycling Zielkonflikte im Kontext von Abfallwirtschaft, Boden- und Grundwasserschutz sowie rechtlichen Vorgabe mit den Beispielen rezyklierte Gesteinskörnungen und RC-Gips. T2 - IX. Baustoffseminar CY - Weimar, Germany DA - 11.03.2020 KW - Kreislaufwirtschaft KW - Baustoffrecycling KW - Ressourcenschonung PY - 2020 AN - OPUS4-51436 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weimann, Karin T1 - New sources for secondary gypsum N2 - In order to protect natural gypsum deposits and to compensate for the decreasing amount of Flue Gas Desulfurization (FGD) gypsum it is necessary to develop and explore new sources of gypsum. For this purpose, the potentials of different gypsum wastes are investigated in the study “GipsRec 2.0”, funded by the Federal Ministry of Education and Research (Germany). On the one hand, the project worked on a new processing technology for gypsum fiberboards (GFB). While the recycling of gypsum plasterboards has already been carried out on an industrial scale for several years, the recycling of gypsum fiberboards (GFB) has proven to be challenging. Gypsum fiberboards from demolition sites and offcuts from GFB production were used for these investigations. The tests were conducted on a technical scale. Furthermore, various synthetic gypsums are being investigated with regard to their suitability for gypsum production. The analyses are carried out on production residues. In this project, a promising process for gypsum fiberboard recycling could be developed, as well as other waste gypsums are investigated and evaluated with regard to their potential as secondary raw material. In addition, selected process routes are assessed for their environmental impact using a life cycle assessment (LCA) approach. T2 - RILEM - V International Conference Progress of Recycling in the Built Environment CY - Weimar, Germany DA - 10.10.2023 KW - Gypsum recycling KW - Gypsum fiberboards and synthetic gypsum KW - Environmental evaluation PY - 2023 AN - OPUS4-60316 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Hydro-Touch test - Evaluation of Transfer of Microorganisms to Non-porous Surfaces and their antimicrobial Activity N2 - This presentation describes a new test procedure that allows to determine the transfer of microorganisms to surfaces and to measure the antimicrobial efficacy of those surfaces. The main improvement of the method is that is assesses the effect of the surfaces under semi-dry, realistic conditions by transferring microorganisms via a gelatin pad linked to a stamp of defined weight. Comparing the performance of the established antimicrobial materials with currently used wet test methods and the newly developed method shows reduced antimicrobial activity of those materials under semi-dry conditions. T2 - 64. Sitzung des DIN NA 176-03-06 AA „Chemische Desinfektionsmittel und Antiseptika in der Humanmedizin“ CY - Online meeting DA - 29.09.2025 KW - Antimicrobial surfaces KW - Standardization PY - 2025 AN - OPUS4-64870 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nordholt, Niclas T1 - Phenotypic heterogeneity in bacterial lag times and antibiotic tolerance induced by the disinfectant glutaraldehydePhenotypic heterogeneity in bacterial lag times and antibiotic tolerance induced by the disinfectant glutaraldehyde N2 - Phenotypic heterogeneity in clonal bacterial populations can be considered a preliminary stage of functional differentiation, which may increase population fitness in fluctuating environments. Here, we investigated how transient exposure of clonal bacterial populations to residual amounts of a commonly used disinfectant, glutaraldehyde (GTA), induces phenotypic heterogeneity, ensuring survival of the population upon sudden challenge with high doses of antibiotics. Using the ScanLag system, we found that exposure to GTA resulted in wide lag-time distributions across different bacterial isolates of E. coli, S. aureus, and P. aeruginosa. Importantly, this was associated with elevated levels of survival (i.e. tolerance) towards lethal doses of antibiotics. As revealed by RNAseq in E. coli, GTA exposure caused global transcriptome remodeling, with more than 1200 differentially expressed genes of diverse biological functions. Several of these genes that were not previously associated with antibiotic tolerance or persistence induced, when overexpressed alone, antibiotic tolerance without showing a lag phenotype. This suggests that exposure to GTA induces unspecific, lag-dependent and specific, lag-independent tolerance to antibiotics in clonal bacterial populations. These findings have implications for 1.) settings where disinfectants and antibiotics are used in close proximity, such as hospitals and animal husbandry, and 2.) for the selection dynamics of tolerant pheno- and genotypes in fluctuating environments because of the trade-off that arises from exiting lag and resuming growth as fast as possible and maintaining antibiotic tolerance. This trade-off may be weakened by phenotypically heterogeneous clonal populations as induced by GTA. T2 - FAST REAL Project Meeting Tartu CY - Tartu, Estonia DA - 16.06.2025 KW - Biocides KW - Biocide resistance KW - Phenotypic heterogeneity KW - Glutaraldehyde KW - Disinfectants PY - 2025 AN - OPUS4-63834 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kanaris, Orestis T1 - Identification of metabolic niches and their association to the persistence of antibiotic resistant bacteria in wastewater N2 - Wastewater treatment plants (WWTP) are hotspots for the development and spread of antimicrobial resistance. Antimicrobial resistant bacteria (ARB) can persist in the environment for long periods of time, despite metabolic fitness costs that often arise with resistance. Recent research efforts are striving to uncover the role of bacterial metabolism for the ecology and evolution of antibiotic resistance. The aim of this study is to understand the ecological mechanisms, which allow ARB to persist in the environment. More specifically, we aim to identify metabolic niches that can select for and against resistant bacteria. 62 E. coli strains isolated from different WWTPs with different levels of resistance to 14 antibiotics and 3 disinfectants were assembled, sequenced, and phenotypically characterized. Next, genome scale metabolic models (GEMs) were constructed, and the growth of the strains was simulated in the presence of 298 different carbon sources. Furthermore, the growth rates of the isolates were measured in the presence of 3 carbon sources to verify the model predictions. Competition experiments with synthetic microbial communities consisting of a selection of 10 WWTP isolates, 5 of which were antibiotic resistant and 5 sensitive, were carried out in minimal medium with different carbon sources. Population dynamics modelling was used to simulate the competition of isolates under different conditions. The isolates have a wide range of susceptibility to the antibiotics, while disinfectants result in a narrower range of susceptibility. GEMs identified 40 carbon sources that can be utilized for growth only by a portion of all the isolates. The prediction accuracy of the GEMs was 93% in the case of D-malate. A range of WWTP isolates were identified which use D-malate as carbon source and are susceptible to specific antibiotics. In contrast, antibiotic-resistant WWTP isolates were identified that did use sucrose as carbon source but not D-malate. Competition experiments demonstrated that changing the carbon source of the medium from sucrose to D-malate resulted in selection against the resistant isolates. Modelling the competition between isolates under different conditions suggests that adding a carbon source to a bacterial community under specific conditions could exclude resistant bacteria from a microbial community. Our data suggest that changing the available carbon source could shift the selection advantage between resistant and susceptible bacterial strains. If this strategy is confirmed experimentally in complex microbial communities, it could be applied to reduce the number of ARB in environments such as wastewater. T2 - FEMS micro Konferenz CY - Milan, Italy DA - 14.07.2025 KW - AMR KW - Wastewater KW - Genome-scale metabolic model PY - 2025 AN - OPUS4-64659 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Marano, Roberto T1 - A Customizable Procedure for Predicting Antibiotic Resistance Selection on Novel Antimicrobial Coatings N2 - The global burden of antimicrobial resistance (AR) has manifested in an increasing number of deaths attributable to antibiotic-resistant bacteria (ARB) in recent years, with projections indicating a continued rise. Combating AR requires a multifaceted approach, one aspect of which involves preventing the spread of ARB in hospital environments via high-touch surfaces, which are known contributors to nosocomial infections. In conjunction with routine disinfection protocols and infection prevention measures, antimicrobial surfaces or antimicrobial coatings (AC) are increasingly being investigated and implemented to reduce microbial transmission via high-touch surfaces, thereby mitigating their spread in healthcare settings. However, similar to antibiotics, prolonged use of such surfaces may lead to the direct or indirect selection of ARB. To prevent this, targeted tests must be developed to predict potential AR selection before AC implementation. Materials and Methods As part of the Horizon-Europe-funded project "STOP" (Grant Agreement ID: 101057961), a novel antimicrobial coating is being developed and tested to reduce pathogen transfer on surfaces without selecting for ARB. To this end, two bacterial libraries (80 strains each) were assembled from the two species most associated with AR-attributable mortality worldwide, Escherichia coli and Staphylococcus aureus, as identified in the most recent comprehensive study [1]. Each library maintains a 50/50% ratio of strains resistant or sensitive to third-generation cephalosporins (E. coli) and methicillin (S. aureus), respectively—representing two of the most widespread resistance profiles. An adapted ISO 22196 method was developed using a reference benchmark antimicrobial surface (i.e., copper), with stainless steel serving as a control. The goal was to infer potential advantages of copper-unrelated antibiotic resistance phenotypes on the tested surface. Results Metadata, genomic data, and antibiotic susceptibility testing (AST) data were collected for all selected strains in each library, ensuring diversity in sequence types (ST) of clinical relevance, antibiotic resistance gene profiles, and geographical origins. The method was calibrated on copper surfaces using a reference E. coli strain, establishing the initial parameters required for investigators to customize the test for a given AC. Procedural reproducibility was assessed by comparing results from independent operators. Discussion The two libraries are currently being screened against the selected copper surfaces to identify potential associations between the resistance phenotypes of the tested species and their observed survival rates post-exposure. Three mutually exclusive outcomes are anticipated: (i) a statistically significant survival advantage of resistant strains compared to sensitive strains, (ii) an inverse scenario where sensitive strains exhibit higher survival, or (iii) no significant difference between the two groups. Furthermore, post hoc principal component analysis utilizing metadata and AST data may help elucidate genetic traits that confer a survival advantage on the tested AC. Conclusions This test aims to assist developers of antimicrobial coatings and materials in assessing potential selective pressures toward ARB before these products are implemented and evaluated under real-life conditions. T2 - ESB Conference CY - Torino, Italy DA - 07.09.2025 KW - Antimicrobial-resistance KW - Surface antimicrobial testing KW - Materials testing PY - 2025 AN - OPUS4-64569 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kanaris, Orestis T1 - Metabolic niches and persistence of antibiotic resistant bacteria in the environment N2 - Background and Aim: Wastewater treatment plants are considered as hotspots for the development and spread of antimicrobial resistance. Antimicrobial resistant bacteria (ARB) can persist in the environment for long periods of time, despite metabolic fitness costs that can arise with resistance. We are interested in understanding the mechanisms, which allow ARB to persist in the environment. More specifically, we want to identify metabolic niches that can select for resistant bacteria. Procedure/Method: 62 E. coli strains isolated from different WWTPs in Norway were used. The isolates have different levels of resistance to 14 antibiotics. The susceptibility of the isolates to 3 disinfectants was determined. In addition, genome scale metabolic models (GEMs) were constructed and the growth of the strains was simulated in the presence of 198 different carbon sources. Furthermore, the growth rates of the isolates were measured in the presence of 3 carbon sources. Findings/Results: Many of the isolates have high resistance to multiple antibiotics but only few of the isolates have higher minimum inhibitory concentrations to the disinfectants, compared to an E. coli laboratory strain. With the GEMs, we identified 40 carbon sources that can be utilized for growth only by a portion of all the isolates. The prediction accuracy of the GEMs was 93% in the case of D-Malate. A group of 10 isolates was identified of which 5 isolates are resistant to ciprofloxacin, gentamicin and tetracycline and can grow on Sucrose but not on D-Malate and the other 5 isolates are susceptible to the same 3 antibiotics but can grow on D-Malate and not on Sucrose. Implications/Applications: Our data suggest that changing the available carbon source could shift the selection advantage between resistant and susceptible bacterial strains. If this strategy is confirmed experimentally, it could be applied to reduce the number of ARB in environments such as wastewater. T2 - International Biodeterioration and Biodegradation Symposium 19 CY - Berlin, Germany DA - 09.09.2024 KW - Antimicrobial resistance KW - Wastewater PY - 2024 AN - OPUS4-61412 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Marano, Roberto T1 - Antimicrobial coatings: modes of action, microbiological efficacy testing, and resistance evolution N2 - Within the Horizon-Europe funded project “STOP: Surface Transfer Of Pathogens”, Grant agreement 101057961, Working Package 6 is currently working on developing tests aimed at predicting possible selection and/or evolution of antibiotic resistance onto antimicrobial coatings meant for high-touch surfaces. This presentation describes the devised protocols and the preliminary results of their application on copper as a benchmark antimicrobial material. T2 - STOP-project Meeting CY - Sofia, Bulgaria DA - 27.02.2025 KW - Antimicrobial-resistance KW - Surface antimicrobial testing KW - Materials testing PY - 2025 AN - OPUS4-64567 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Mechanisms and evolution of resistance to antimicrobial biocides N2 - Antimicrobial resistance (AMR) is a global health problem with the environment being an important compartment for the evolution, selection and transmission of AMR. These processes are impacted by pollution with antibiotics. However, antimicrobial biocides used as disinfectants and material preservatives are major pollutants exceeding the antibiotic market in terms of chemical diversity and mass. The aim of our work is to understand the mechanisms and risks of biocides for resistance and antibiotic cross-resistance evolution in bacteria to optimize their application and safeguard their efficacy. Our work shows that biocides have the potential to affect evolutionary processes towards AMR by increasing the rates of de-novo mutation and conjugation. Importantly, widely used compounds such as chlorhexidine and quaternary ammonium compounds (QACs) affect rates of mutation and conjugation at environmentally relevant concentrations. Furthermore, we show that single-cell phenotypic heterogeneity regarding tolerance (persistence) determines survival against specific biocides including QACs and isopropanol. Mechanistic investigations reveal that known antibiotic persister mechanisms contribute to persister formation to biocides. The evolution of high-level tolerance to different biocides is linked to the initial persister level and the evolution of specific genetically encoded mechanisms related to properties of the cell envelope. Biocide-tolerant strains have a selective advantage in the presence of environmentally-relevant concentrations of antibiotics, which could lead to the stabilization of biocide tolerance in environments where biocides and antibiotics co-occur (e.g. wastewater, animal stables). Taken together, our work shows the importance of assessing the contribution of biocides on evolution and selection of AMR in the environment. T2 - EMBO Symposium on Mechanisms of drug resistance and tolerance in bacteria, fungi, and cancer CY - Heidelberg, Germany DA - 18.03.2025 KW - Antimicrobial surfaces KW - Biocides KW - Antimicrobial resistance PY - 2025 AN - OPUS4-64866 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Marano, Roberto T1 - Antimicrobial coatings: modes of action, microbiological efficacy testing, and resistance evolution N2 - Antimicrobial coatings and materials on high touch surfaces can provide additional level of protection to periodic disinfection cycles by reducing bacterial loads. However, different coatings and materials assert their antimicrobial activity in different ways, and it is not clear whether they could pose detrimental selective pressure towards antibiotic-resistant bacteria. This talk elucidates modes of actions and current knowledge gaps in testing antimicrobial resistance on antimicrobial surfaces.” T2 - STOP Antimicrobial Coating Conference CY - Mons, Belgium DA - 05.12.2024 KW - Antimicrobial-resistance KW - Surface antimicrobial testing KW - Materials testing PY - 2025 AN - OPUS4-64566 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Marano, Roberto T1 - A Customizable Procedure for Predicting Antibiotic Resistance Selection on Novel Antimicrobial Coatings N2 - This presentation introduceda new methodological approach developed to test antimocrobials implemented on high touch surfaces, inlcuding preliminary results on its use on reference antimicrobial materials. The seminar was organized by the 'Fast-real' project, funded by the Horizon Europe (project ID: 101159721). T2 - Novel strategies and considerations in fighting pathogens CY - Tartu, Estonia DA - 16.06.2025 KW - Antimicrobial-resistance KW - Surface antimicrobial testing KW - Materials testing PY - 2025 AN - OPUS4-64568 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Resistance evolution towards biocides and antimicrobial surfaces N2 - Biocides, including disinfectants and antimicrobial surfaces (AMCs), are important to prevent the spread of pathogens and antimicrobial resistant bacteria via surfaces. However, concerns have been raised about 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 and co-resistance. We need to understand the mechanisms and risks of disinfectants and AMCs for resistance and cross-resistance evolution to optimize their application and safeguard their long-term efficacy. We used adaptive laboratory evolution (ALE) experiments based on repeated exposure of bacteria to disinfectants. Our results show that repeated disinfection of E. coli with benzalkonium chloride in suspension results in a 2000-fold increase in survival within 5 exposure cycles. Adaption is linked to the initial presence of persister cells highly tolerant to benzalkonium chloride. We used the same approach to develop standardizable ALE experiments to determine resistance evolution to AMCs. The results highlight rapid adaptation of E. coli and P. aeruginosa towards copper surfaces. Moreover, there are multiple situations in the clinic or in the environment in which biocides and antibiotics co-occur and in which combination effects can shape their antimicrobial activity or their selective effects. Our work with P. aeruginosa shows prevalent combination effects of biocides and antibiotics, ranging from synergy to antagonism and resulting in the selection for or against antibiotic resistant strains. The combination effects are dependent on the biofilm mode-of-growth, manifesting in apparent differences in the structural arrangement of antibiotic sensitive and resistant strains in biofilms exposed to combinations. Furthermore, biocides affect rates of mutation and horizontal gene transfer, thereby having a potential facilitating effect on resistance evolution. Taken together, our work shows that the role of biocides as potential drivers of resistance evolution and selection deserves further study and regulative action. T2 - Eurobiofilms 2022 CY - Palma, Spain DA - 31.08.2022 KW - Antimicrobial resistance KW - Bacteria KW - Biofilms KW - Biocides KW - Antimicrobial surfaces PY - 2022 AN - OPUS4-55608 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Biocides as drivers for the evolution of antimicrobial resistance N2 - This presentation provides an overview about how biocides drive the evolution of antimicrobial resistance during application and as pollutants in the environment. The presentation shows that biocides can lead to heterogeneous killing, facilitating tolerance evolution. This evolution is related to decreased susceptibility to antibiotics and has potential for co-selection. In contrast, evolved tolerance can limit antibiotic evolvability via epistatic interactions. Moreover, biocides can co-select for antibiotic resistance in wastewater and affect rates of mutation and horizontal gene transfer. Biocides and antibiotics show strong combination effects with consequences for selection of antibiotic resistance. T2 - Novel strategies and considerations in fighting pathogens CY - Tartu, Estonia DA - 16.06.2025 KW - Antimicrobial surfaces KW - Biocides KW - Antimicrobial resistance KW - Standardization PY - 2025 AN - OPUS4-64867 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Biocides as drivers for the Selection and evolution of antimicrobial resistance N2 - Antimicrobial resistance (AMR) is a global health problem with the environment being an important compartment for the evolution, selection and transmission of AMR. These processes are impacted by pollution with antibiotics. However, antimicrobial biocides used as disinfectants and material preservatives are major pollutants exceeding the antibiotic market in terms of chemical diversity and mass. The aim of our work is to understand the mechanisms and risks of biocides for resistance and antibiotic cross-resistance evolution in bacteria to optimize their application and safeguard their efficacy. We use adaptive laboratory evolution experiments, phenotypic characterization, single-cell analysis, whole genome sequencing, and competition experiments to investigate AMR evolution and selection of the model organism E. coli in the presence of biocides. Our work shows that biocides have the potential to affect evolutionary processes towards AMR by increasing the rates of de-novo mutation and conjugation. Importantly, widely used compounds such as chlorhexidine and quaternary ammonium compounds (QACs) affect rates of mutation and conjugation at environmentally relevant concentrations. Furthermore, we show that single-cell phenotypic heterogeneity regarding tolerance (persistence) determines survival against specific biocides including QACs and isopropanol. Mechanistic investigations reveal that known antibiotic persister mechanisms contribute to persister formation to biocides. The evolution of high-level tolerance to different biocides is linked to the initial persister level and the evolution of specific genetically encoded mechanisms related to properties of the cell envelope. Biocide-tolerant strains have a selective advantage in the presence of environmentally-relevant concentrations of antibiotics, which could lead to the stabilization of biocide tolerance in environments where biocides and antibiotics co-occur (e.g. wastewater, animal stables). Taken together, our work shows the importance of assessing the contribution of biocides on evolution and selection of AMR in the environment. T2 - 10th Symposium on Antimicrobial Resistance in Animals and the Environment (ARAE) CY - Berlin, Germany DA - 30.06.2025 KW - Antimicrobial surfaces KW - Biocides KW - Antimicrobial resistance KW - Standardization PY - 2025 AN - OPUS4-64869 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Biocides as drivers for the evolution of antimicrobial resistance N2 - This presentation provides an overview about how biocides drive the evolution of antimicrobial resistance during application and as pollutants in the environment. The presentation shows that biocides can lead to heterogeneous killing, facilitating tolerance evolution. This evolution is related to decreased susceptibility to antibiotics and has potential for co-selection. In contrast, evolved tolerance can limit antibiotic evolvability via epistatic interactions. Moreover, biocides can co-select for antibiotic resistance in wastewater and affect rates of mutation and horizontal gene transfer. Biocides and antibiotics show strong combination effects with consequences for selection of antibiotic resistance. T2 - Vorstellungsvortrag zur Habilitation FU Berlin CY - Berlin, Germany DA - 15.05.2025 KW - Antimicrobial surfaces KW - Biocides KW - Antimicrobial resistance KW - Standardization PY - 2025 AN - OPUS4-64873 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Resistance evolution to antimicrobial biocides N2 - This talk discusses resistance evolution to antimicrobial biocides. It shows (i) that biocides show heterogeneous killing facilitating tolerance evolution, (ii) that serial transfer at subinhibitory concentrations is not appropriate to model evolutionary adaptation to disinfection, (iii) that biocides affect rates of mutation and horizontal gene transfer Biocides, and (iv) that antibiotics show strong combination effects. T2 - Evolutionary Biology meets the Antibiotic Crisis vol. 2 CY - Plön, Germany DA - 24.09.2024 KW - Antimicrobial resistance KW - Bacteria KW - Standardization KW - Biocides PY - 2024 AN - OPUS4-61545 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Dr. Frank Schreiber and Work on Biocide Resistance at BAM N2 - This talk details the career path of Dr. Frank Schreiber and his work on biocide resistance at BAM. Biocides are antimicrobial products for defined applications (disinfectants, preservatives, pest control). Biocides show heterogeneous killing facilitating resistance/tolerance evolution. Adaptation to biocides has effects on growth and selection. T2 - Vortrag an der Berliner Hochschule für Technik CY - Berlin, Gemany DA - 07.06.2024 KW - Antimicrobial resistance KW - Bacteria KW - Standardization KW - Biocides PY - 2024 AN - OPUS4-61543 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Biocides as drivers for the evolution and selection of antimicrobial resistance N2 - This presentation provides an overview about how biocides drive the evolution of antimicrobial resistance during application and as pollutants in the environment. The presentation shows that biocides can lead to heterogeneous killing, facilitating tolerance evolution. This evolution is related to decreased susceptibility to antibiotics and has potential for co-selection. In contrast, evolved tolerance can limit antibiotic evolvability via epistatic interactions. Moreover, biocides can co-select for antibiotic resistance in wastewater and affect rates of mutation and horizontal gene transfer. Biocides and antibiotics show strong combination effects with consequences for selection of antibiotic resistance. T2 - 12. Dresdner Wasserseminar ' Wasser und Verunreinigung' CY - Dresden, Germany DA - 26.06.2025 KW - Antimicrobial surfaces KW - Biocides KW - Antimicrobial resistance KW - Standardization PY - 2025 AN - OPUS4-64868 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Beyond Antibiotics – Biocides as Drivers of Environmental AMR N2 - This presentation provides an overview about how biocides drive the evolution of antimicrobial resistance during application and as pollutants in the environment. It also discusses the contribution of biocides for the environmental transmission of AMR. T2 - OneBridge: Making environmental AMR Surveillance Fit for Purpose: Data Integration and the Ecology of Resistance CY - Dresden, Germany DA - 06.10.205 KW - Antimicrobial surfaces KW - Biocides KW - Antimicrobial resistance KW - Standardization PY - 2025 AN - OPUS4-64872 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Resistance evolution towards biocides and antimicrobial surfaces N2 - This presentation describes our work at BAM on resistance evolution towards biocides and antimicrobial surfaces. T2 - Break biofilms workshop CY - Vienna, Austria DA - 16.01.2023 KW - Antimicrobial resistance KW - Bacteria KW - Biofilms KW - Biocides PY - 2023 AN - OPUS4-57857 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Selina T1 - Antimicrobial resistance in soil microbes mediated by resistance evolution and horizontal gene transfer (HGT) N2 - Biocides are in contact with soils through direct application and passive leaching from protected materials. Consequently, soil microorganisms are exposed to biocides even though they are not their primary targets. Soil is a large reservoir of microbial diversity and has been hypothesized to be a crucial factor for the evolution and spread of antimicrobial resistance. Currently, there is little knowledge on how biocides used to protect materials affect the evolution and spread of resistance. Thus, our aim is to investigate the risk for the evolution of biocide resistance and cross-resistance to antibiotics. In addition, we aim to elucidate the affect of biocides on the spread of resistance via horizontal gene transfer (HGT). In adaptive laboratory evolution experiments we cultured selected model soil microorganism with representative biocides under selection regimes with increasing and stable biocide concentrations followed by antibiotic and biocide cross-resistance determination. Moreover, we investigate if the selected biocides affect the rates of de novo mutations and HGT of plasmids that carry resistance genes among soil microorganism. Our results show only small increases of biocide resistance during serial transfers under increasing biocide concentrations. One reason for this might be the narrow selective window for biocide resistance due to steep dose-response relationships. Furthermore, our results indicate that a stable low-level biocide regime did not select for high level cross-resistance to antibiotics and other biocides. Moreover, material preservatives affected the rates of HGT via conjugation and the mutation rates at sub-inhibitory concentrations. The results will enable future risk assessment regarding resistance evolution for biocides used as material preservatives. T2 - 4th Evo Eco PhD Meeting CY - Lutherstadt Wittenberg DA - 04.03.2020 KW - Microbiology KW - Biocides KW - Horizontal gene transfer HGT KW - Resistance evolution KW - Antimicrobial resistance PY - 2020 AN - OPUS4-51313 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Biocide resistance risk assessment N2 - This presentation details the current status of biocide resistance risk assessment. T2 - Risk assessment of biocide and antibiotic resistance CY - Online meeting DA - 09.03.2022 KW - Antimicrobial resistance KW - Antimicrobial coating KW - Standardization KW - Biocides KW - Risk assessment PY - 2022 UR - https://www.gu.se/en/biocide/risk-assessment-of-biocide-and-antibiotic-resistance AN - OPUS4-56235 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nordholt, Niclas T1 - Persistence against benzalkonium chloride promotes rapid evolution of tolerance under periodic disinfection N2 - A presentation given at the VAAM conference 2022, summarizing our findings published in the research paper "Persistence against benzalkonium chloride promotes rapid evolution of tolerance under periodic disinfection" T2 - Annual conference of the association for general and applied microbiology (VAAM) 2022 CY - Düsseldorf, Germany DA - 21.02.2022 KW - Persistence KW - Biocides KW - Evolution KW - Cross-resistance KW - Biocide tolerance KW - Disinfection PY - 2022 AN - OPUS4-54437 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nordholt, Niclas T1 - Phenotypic heterogeneity in bacterial lag times and antibiotic tolerance induced by the disinfectant glutaraldehyde N2 - Phenotypic heterogeneity in clonal bacterial populations can be considered a preliminary stage of functional differentiation, which may increase population fitness in fluctuating environments. Here, we investigated how transient exposure of clonal bacterial populations to residual amounts of a commonly used disinfectant, glutaraldehyde (GTA), induces phenotypic heterogeneity, ensuring survival of the population upon sudden challenge with high doses of antibiotics. Using the ScanLag system, we found that exposure to GTA resulted in wide lag-time distributions across different bacterial isolates of E. coli, S. aureus, and P. aeruginosa. Importantly, this was associated with elevated levels of survival (i.e. tolerance) towards lethal doses of antibiotics. As revealed by RNAseq in E. coli, GTA exposure caused global transcriptome remodeling, with more than 1200 differentially expressed genes of diverse biological functions. Several of these genes that were not previously associated with antibiotic tolerance or persistence induced, when overexpressed alone, antibiotic tolerance without showing a lag phenotype. This suggests that exposure to GTA induces unspecific, lag-dependent and specific, lag-independent tolerance to antibiotics in clonal bacterial populations. These findings have implications for 1.) settings where disinfectants and antibiotics are used in close proximity, such as hospitals and animal husbandry, and 2.) for the selection dynamics of tolerant pheno- and genotypes in fluctuating environments because of the trade-off that arises from exiting lag and resuming growth as fast as possible and maintaining antibiotic tolerance. This trade-off may be weakened by phenotypically heterogeneous clonal populations as induced by GTA. T2 - 1st International Conference on Emergent Functions of Bacterial Multicellularity CY - Berlin, Germany DA - 06.01.2025 KW - Disinfectants KW - Biocides KW - Phenotypic heterogeneity PY - 2025 AN - OPUS4-62462 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - BIOCIDE N2 - This presentation gives an overview about the BIOCIDE project performed with the Aquatic Pollutants joint call. T2 - Aquatic Pollutants TransNet workshop CY - Online meeting DA - 09.11.2022 KW - Antimicrobial resistance KW - Bacteria KW - Biofilms KW - Biocides KW - Risk assessment KW - Wastewater PY - 2022 AN - OPUS4-56265 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koerdt, Andrea T1 - Hydrogen storage & Microbiologically influenced corrosion - Improved test system for Stability and Durability of the Materials & Gas N2 - Underground hydrogen storage (UHS) is a strategic step towards implementing the hydrogen economy. Achieving the required infrastructure by 2050 necessitates advancements in hydrogen-dedicated assets and the evaluation of existing infrastructure. The unique conditions in UHS require an experimental set-up to simulate UHS operating conditions, which allows to assess the readiness of current storage and transmission for hydrogen, and develop new technologies for material-resistance, operational-simulations, and risk-assessments. In addition to the physical/chemical conditions in UHS (e.g., salinity, hydrogen concentration, operating temperature/-pressure, water content), biological threats must also be considered. Therefore, we present here a high-pressure-set-up, developed for research/-industrial testing purposes. Currently, UHS-experiments for microbiologically-influenced-corrosion (MIC) are performed in standard autoclaves with relatively high volumes/pressures; they were primarily designed for material-specific investigations. While these methods provided some useful information for biological questions, they had significant limitations. Besides, the rapid depressurization that occurs with standard autoclaves can greatly affect materials, especially amorphous materials like polymers, causing damage that isn't due to the actual hydrogen storage. This presents a challenge, as the test results may not accurately reflect real-world conditions. To address these issues, specialized autoclaves have been developed to allow for slower depressurization while also enabling continuous monitoring of gases and liquids during the experiment. Such modifications could help obtain more accurate and reliable data. The novel UHS-simulation-set-up presented here is designed with a controlled independently temperature and pressure. Field samples can be used to mimic geology, water chemistry, construction materials, and microbiological conditions. Most significant advantages of the set-up are: 1. It allows for liquid addition during the test, enabling the study of biocides or the evaluation of operating setups. 2. It permits liquid/-gas sampling during the test, allowing for more efficient monitoring of testing conditions and a better understanding of the process over time. Additionally, a low-release function is added, which is particularly important for studying MIC to avoid negative side effects, on the material (e.g. polymers/corrosion product-layer/cells itself) which might occur due to the fast pressure release. T2 - MATHEA | MATerials in Hydrogen related Energy Applications 2025 CY - Hamburg, Germany DA - 24.06.2025 KW - MIC KW - MISTRAL KW - Underground storage KW - Hydrogen KW - Polymer KW - Metal PY - 2025 AN - OPUS4-63567 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kanaris, Orestis T1 - Consequences of tolerance to disinfectants on the evolution of antibiotic resistance in E. coli N2 - Biocides are used as disinfectants and preservatives; one important active substance in biocides is benzalkonium chloride (BAC). BAC-tolerant bacterial strains can survive short treatments with high concentrations of BAC. BAC tolerance and resistance have been linked to antibiotic resistance. Here, the selection dynamics between a BAC-tolerant Escherichia coli strain and a sensitive wild type were investigated under four conditions: in the absence of antibiotics and in the presence of three different sub-inhibitory concentrations of the antibiotic ciprofloxacin in liquid cultures. The wild type was selected over the BAC-tolerant strain in the absence of antibiotics, while the BAC-tolerant strain was selected over the wild type at all ciprofloxacin concentrations investigated, with a minimum selection concentration (MSC) of 1/10th of the minimum inhibitory concentration (MIC) of the wild type. Furthermore, the evolvability of resistance of the two strains to inhibitory concentrations of ciprofloxacin was assessed by performing a serial dilution evolution experiment with gradually increasing ciprofloxacin concentrations. The wild type had a higher probability to develop resistance to ciprofloxacin than the tolerant strain. By the end of the evolution experiment both strains evolved to grow at the highest ciprofloxacin concentration investigated, which was 2048 ×MIC of the wild type. The importance of these results is highlighted by the fact that concentrations of ciprofloxacin well above the calculated MSC can be found in environmental samples such as hospital wastewaters and livestock slurry. In turn, BAC is used as a disinfectant in the same settings. Thus, the selection of BAC-tolerant strains at sub-inhibitory concentrations of ciprofloxacin can contribute to the stabilization and spread of BAC-tolerance in natural populations. The prevalence of such strains can impair the effects of BAC disinfections. T2 - µClub seminar series CY - Berlin, Germany DA - 15.12.2023 KW - Antimicrobial resistance PY - 2023 AN - OPUS4-59222 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Resistenzen von Bakterien gegen Biozide – Evolution, Mechanismen und Methoden N2 - Diese Präsentation gibt einen Überblick über die Aktivitäten zum Thema Biozidresistenz an der BAM. T2 - Life Science Nord - Online-Update Hygiene und Infektionsprävention CY - Online meeting DA - 14.06.2022 KW - Antimikrobielle Resistenz KW - Antmikrobielle Oberflächen KW - Standardisierung KW - Biozide KW - Risikobewertung PY - 2022 UR - https://vimeo.com/722198443 AN - OPUS4-56236 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nordholt, Niclas T1 - The disinfectant glutaraldehyde induces antibiotic tolerance underpinned by Phenotypic Heterogeneity and transcriptome remodeling N2 - Glutaraldehyde (GTA) is commonly used to disinfect medical equipment, in animal husbandry and in hydraulic fracturing. Its wide use bears the risk that microorganisms in different environments are exposed to potentially non-lethal doses of glutaraldehyde. To date, little is known about the effects of glutaraldehyde on the susceptibility of bacteria to antibiotics and its role in the selection of tolerant phenotypes. Objectives • To determine the effect of glutaraldehyde exposure on the survival of E. coli, S. aureus and P. aeruginosa to antibiotics • To find the mechanistic basis for antibiotic tolerance upon glutaraldehyde exposure Materials & Methods Four bacterial isolates were exposed to sub-inhibitory glutaraldehyde. Antibiotic tolerance was determined by time-kill assays. Regrowth dynamics (lag times) were determined with ScanLag. E. coli was further investigated, using RNAseq to identify genes and processes involved in antibiotic tolerance. Mutants of candidate genes were screened for their antibiotic tolerance and heterogeneous target gene expression under stressed and unstressed conditions. Results Short-term exposure to sub-inhibitory levels of glutaraldehyde induced tolerance to high doses of bactericidal antibiotics. Tolerance to antibiotics was associated with highly heterogeneous regrowth dynamics and global transcriptome remodeling. Differentially expressed genes represented diverse biological functions and cellular components, including antibiotic efflux, metabolic processes, and the cell envelope. The heterogeneous regrowth dynamics and the diversity of the differentially expressed genes are likely related to the unspecific mode-of-action of glutaraldehyde. Among the many differentially expressed genes, several genes were identified that were not previously associated with antibiotic tolerance or persistence, which, when overexpressed alone, increased antibiotic tolerance. Conclusion Our results highlight how the big advantage of a disinfectant, its unspecific mode-of-action, can induce transient tolerance to antibiotics in bacteria. These findings have implications for 1.) settings where disinfectants and antibiotics are used in proximity, such as hospitals and animal husbandry, and 2.) for the selection dynamics of tolerant bacteria in fluctuating environments because of the trade-off that arises from overcoming the lag phase as fast as possible and maintaining antibiotic tolerance. T2 - VAAM Jahrestagung 2023 CY - Göttingen, Germany DA - 10.09.2023 KW - Glutaraldehyde KW - Disinfectants KW - Biocides KW - Antibiotics KW - Bacteria PY - 2023 AN - OPUS4-58439 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Resistance evolution towards biocides and antimicrobial surfaces N2 - This talk discusses resistance evolution towards biocides and antimicrobial surfaces. It shows (i) that biocides affect rates of mutation and horizontal gene transfer, (ii) that biocides show heterogeneous killing facilitating tolerance evolution, and (iii) that biocides and antibiotics show strong combination effect on growth and selection. T2 - STOP project internal seminar CY - Online meeting DA - 24.04.2024 KW - Antimicrobial resistance KW - Bacteria KW - Standardization KW - Biocides KW - Antimicrobial surfaces PY - 2024 AN - OPUS4-61546 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Physiological and evolutionary consequences of exposing Pseudomonas aeruginosa to biocide-antibiotic combinations N2 - Antimicrobials can exert specific physiological effects when used in combination that are different from those when applied alone. These effects include physiological effects (i.e. synergy, antagonism and suppression) as well as evolutionary effects on the selection of resistant strains (i.e. cross-resistance and collateral sensitivity). While combination effects have been extensively mapped for antibiotic-antibiotic combinations, the combination effects of antibiotics with antimicrobials used as biocides or antiseptics have not been systematically investigated. Here, we investigated the physiological and evolutionary consequences of combinations of antibiotics (meropenem, gentamicin and ciprofloxacin) and substances used as biocides or antiseptics (octenidine, benzalkonium chloride, cetrimonium bromide, chlorhexidine, povidone-iodine, silver) on growth and selection of Pseudomonas aeruginosa. We find prevalent physiological combination effects with synergy occurring 6 times and antagonism occurring 10 times. The effects are specific to the antibiotic-biocide combination with meropenem showing a tendency for antagonism with biocides (6 of 7), while gentamicin has a tendency for synergy (5 of 7). A particular strong antagonism is apparent for the meropenem-chlorhexidine combination, for which we conducted an in-depth study on the underlying molecular mechanism using RNASeq. Moreover, we find widespread effects of the biocide-antibiotic combinations on selection of P. aeruginosa strains resistant to the antibiotics, including cross-resistance and collateral sensitivity. In conclusion, antibiotics and biocides or antiseptics exert physiological and evolutionary combination effects on the pathogen P. aeruginosa. These effects have consequences for the efficacy of both types of substances and for the selection of antimicrobial resistant strains in clinical applications with combined exposure (e.g. wound care, coated biomaterials). T2 - Antimicrobial Resistance in Biofilms and on Biomaterials CY - Online meeting DA - 10.06.2021 KW - Antimicrobial resistance KW - Antimicrobial coating KW - Biofilms PY - 2021 AN - OPUS4-53162 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nordholt, Niclas T1 - Consequences of BAC tolerance for selection and evolution in the presence of antibiotics N2 - The exposure to antimicrobial substances drives the evolution of antimicrobial resistance. Biocides are antimicrobials used as disinfectants, antiseptics and preservatives. They find application on a large scale in the industrial and medical sector, but also in private households. In terms of mass, the worldwide use of biocides exceeds that of antibiotics. Thus, despite their important role in preventing the spread of pathogens, due to their ubiquity, biocides are suspected to be drivers of the antimicrobial resistance crisis. In our work at BAM we try to understand how biocides contribute to the emergence of AMR, what the underlying adaptation principles and mechanisms are and how they compare to those found for antibiotics. Within our group, I mainly focus on the following two questions: How does phenotypic heterogeneity in bacteria affect the ability to survive treatment with biocides? And what are the consequences of phenotypic heterogeneity for the evolution of resistance to biocides and antibiotics? I will share published and unpublished results which demonstrate that phenotypic heterogeneity can enable the survival of biocide treatment and, through this, facilitate the evolution of AMR. On the other hand, we find that adaptation to a biocide can unexpectedly impair the ability to evolve resistance against an antibiotic. T2 - FEMS summer school for postdocs 2022: Microbial Evolvability Mechanisms: Resistance, Biology, and Strategies to Defeat and Detect CY - Split, Croatia DA - 27.04.2022 KW - Disinfection KW - Biocides KW - Evolution KW - Resistance KW - Biocide tolerance PY - 2022 AN - OPUS4-54846 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Risk Assessment of Biocide Resistance N2 - This presentation details approaches for the risk assessment of biocide resistance. Different methods are presented to acquire the necessary data for such risk assessments. T2 - OECD, 7th Meeting of the Working Party on Biocides CY - Leiden, Netherlands DA - 18.09.2023 KW - Antimicrobial resistance KW - Bacteria KW - Standardization KW - Biocides PY - 2023 AN - OPUS4-59062 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nordholt, Niclas T1 - Progress on STOP-project WP5 and WP6 at BAM N2 - An overview of the progress that has been made on testing of antimicrobial efficacy and method development in the STOP project at BAM. T2 - STOP project meeting 09/2024 CY - Bukarest, Romania DA - 18.09.2024 KW - Antimicrobial surfaces KW - ISO22196 PY - 2024 AN - OPUS4-61178 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Selina T1 - Effect of biocides on the evolution and spread of resistance N2 - Biocides used as material preservatives are in contact with various environments during direct application or passive leaching from protected materials. Antimicrobial resistance (AMR) is a global health problem and the environment is an important compartment for the evolution and transmission of AMR. Soil is an environment with a large reservoir of natural microbial communities and antimicrobial resistance (AMR) genes. Those natural microbial communities are frequently exposed to biocides used as material preservatives. Previous studies have shown that antibiotics, metals and pesticides affect the underlying processes of resistance evolution and spread; namely de novo mutagenesis and horizontal gene transfer by conjugation and transformation in microbial communities. However, it is unknown if active substances used in material preservatives are involved in these processes. We show that biocides used as material preservatives affect rates of mutation and conjugation in microorganism in a species- and substance-dependent manner, while rates of transformation are not directly affected. Our data highlights the importance of assessing the contribution of material preservatives on AMR evolution and spread in the environment. T2 - Microbiome Network Meeting CY - Berlin, Germany DA - 20.07.2022 KW - Biocides KW - Antimicrobial resistance KW - Horizontal gene transfer KW - Mutation rate PY - 2022 AN - OPUS4-56426 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sobisch, Lydia-Yasmin T1 - Biocide resistance evolution of corrosion causing sulfate reducing bacteria N2 - SRB are environmentally and industrially important microorganisms. The disadvantage of their metabolic activity (e.g. sulfate reduction) results in the formation of toxic sulfide that leads to microbial influenced corrosion. SRB have been responsible for biocorrosion of ferrous metal. One of mitigation strategy is the use of biocides. However, it has been shown that various bacteria develop antimicrobial resistance due to excessive use of biocides. Thus, a deeper understanding of the evolution of biocide resistance of SRB is necessary. Three commonly used biocides, THPS, BAC, and GLUT were applied to investigate the susceptibility of Desulfovibrio alaskensis G20.The minimum inhibitory and bactericidal concentration and the killing kinetics of the three biocides was determined. These results will be used to conduct evolution experiments to determine the evolution of resistance towards biocides of SRBs. The outcome of this work can be helpful to improve the management of MIC treatments. T2 - Panel, Pitch & Popcorn by EUROMIC CY - Online meeting DA - 21.06.2021 KW - Biocide KW - Evolution KW - Mircobially influcenced corrosion KW - Sulfate reducing bacteria PY - 2021 AN - OPUS4-56940 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Bakterielle Resistenzen und Toleranzen gegen Desinfektionsmittel und antimikrobielle Oberflächen N2 - Dieser Vortrag beschreibt die Entstehung von bakteriellen Resistenzen und Toleranzen gegen Desinfektionsmittel und antimikrobielle Oberflächen. T2 - Fachtagung für Krankenhaushygiene der Deutschen Gesellschaft für Krankenhaushygiene CY - Essen, Germany DA - 12.05.2023 KW - Antimikrobielle Resistenz KW - Antmikrobielle Oberflächen KW - Standardisierung KW - Biozide PY - 2023 AN - OPUS4-57860 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Biocides As Drivers For Antimicrobial Resistance Evolution In The Environment N2 - Antimicrobial resistance (AMR) is a global health problem with the environment being an important compartment for the evolution, selection and transmission of AMR. These processes are impacted by pollution with antibiotics. However, biocides used as disinfectants and material preservatives are major pollutants by far excceding the market for antibiotics in terms of mass. Our work shows that biocides have the potential to affect evolutionary processes towards AMR by increasing the rates of de-novo mutation and conjugation. These effects depend on the species and biocidal substance. Importantly, chlorhexidine and quaternary ammonium compounds (QACs) affect rates of mutation and conjugation at environmentally relevant concentrations in E. coli. Moreover, our results show a connection between the RpoS-mediated general stress and the RecA-linked SOS response with increased rates of mutation and conjugation, but not for all biocides. Furthermore, our work highlights the potential of biocides to contribute to selection and transmission of AMR. We show that the application of biocides, especially QAC disinfectants, leads to the rapid evolution of tolerance (i.e. increased survival) in adaptive laboratory evolution (ALE) experiments. The evolved tolerant strains have a selective advantage in the presence of environmentally-relevant concentrations of antibiotics, which could lead to the stabilization of biocide tolerance in environments where biocides and antibiotics co-occur (e.g. wastewater, animal stables). ALE experiments with biocide tolerant strains indicate a decreased evolvability of resistance to antibiotics. Taken together, our work shows the importance of assessing the contribution of biocides on evolution, selection and transmission of AMR in the environment. T2 - 6th Environmental Dimension of Antibiotic Resistance (EDAR6) CY - Gothenburg, Sweden DA - 22.09.2022 KW - Antimicrobial resistance KW - Antimicrobial coating KW - Biofilms KW - Biocides KW - Risk assessment PY - 2022 AN - OPUS4-56262 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Resistance evolution towards biocides and antimicrobial surfaces N2 - This talk discusses the work at BAM concerning Resistance evolution towards biocides and antimicrobial surfaces. It shows (i) that biocides affect rates of mutation and horizontal gene transfer, (ii) that biocides show heterogeneous killing facilitating tolerance evolution, and (iii) that biocides and antibiotics show strong combination effect on growth and selection. T2 - Exchange seminar with Nottingham Trent University CY - Berlin, Germany DA - 03.09.2024 KW - Antimicrobial resistance KW - Bacteria KW - Standardization KW - Biocides KW - Antimicrobial surfaces PY - 2024 AN - OPUS4-61548 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nordholt, Niclas T1 - Phenotypic heterogeneity in disinfection: sources and consequences for antimicrobial resistance N2 - A summary of projects here at BAM which investigate the influence of phenotypic heterogeneity on the outcome of disinfection and the influence on antimicrobial resistance. This presentation was given in the Theory Seminar of the Quantitative and Theoretical Biology group of Prof. Oliver Ebenhöh at HHU Düsseldorf T2 - Theory Seminar in the Quantitative and Theoretical Biology group at HHU Düsseldorf CY - Düsseldorf, Germany DA - 24.02.2022 KW - Disinfection KW - Biocides KW - Heterogeneity KW - Resistance PY - 2022 AN - OPUS4-54442 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Deland, Eric T1 - Environmental conditions affect the corrosion product composition of Methanogen induced microbiologically influenced corrosion (Mi-MIC) N2 - Corrosion is a very expensive and serious problem in the different industry sectors, eg. Petroleum-, On- and off-shore, infrastructure. It is estimated that 20% of all corrosion damage is caused by microorganisms or microbiologically influenced corrosion (MIC). Several microorganisms are known to cause corrosion, including sulfate-reducing bacteria, nitrate-reducing bacteria, methanogens etc. For several years, methanogens were regarded as a mild corroder (~0.065 mm/yr), largely due to a lack of detailed investigation on the corrosion mechanism under real-environment simulated conditions. Resulting in the common belief that siderite, a non-conductive compound, is the sole corrosion product (CP) of methanogen-induced MIC (Mi-MIC). To simulate natural environmental conditions, we developed and introduced the multiport flow column system (MFC), a multi-sectional corrosion flow-cell. Using the MFC, we obtained ten times higher corrosion rates than previously reported. With a combination of several analytical techniques, such as ToF-SIMS, SEM-EDS and FIB-SEM, we found strong indication that siderite is not the sole corrosion product of Mi-MIC. The corrosion layers contained phosphorus, oxygen, magnesium, calcium and iron. The differences in the CP between static and dynamic environments demonstrated the impact of testing procedures on the corrosive potential of methanogens. To further verify and deepen our understanding of Mi-MIC, we are currently studying the influence of additional environmental parameters (e.g. pH, salinity, flow rate) on Mi-MIC. Overall, results of this study will expand the current understanding of MIC from both analytical and mechanistic points of view, thus aiding the development of different mitigation strategies for various industry sectors. T2 - ISMOS-8 CY - Online meeting DA - 08.06.2021 KW - Methanogen-induced microbiologically influenced corrosion KW - Carbon steel KW - ToF-SIMS KW - Modelling studies PY - 2021 AN - OPUS4-54041 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Deland, Eric T1 - Environmental conditions impact the corrosion layer composition of Methanogen induced microbiologically influenced corrosion (Mi-MIC) N2 - Microbiologically influenced corrosion (MIC) is a now well-known challenge and affects industry, society and infrastructure. For a long time, the impact of methanogen-induced MIC (Mi-MIC) was underestimated. This was mainly due to the rather low published corrosion rates and the presumed corrosion product siderite, which is not electrically conductive. In our laboratory, we were able to show that this trivialization or underestimation of Mi-MIC was due to the nature of the testing. The static systems used so far do not provide environmentally relevant information about the corrosion rate and the corrosion product, especially for methanogens To further illustrate the importance of the environment on the MIC process, we established a multiport flow column (MFC), to simulate the natural environment. With this method, and in contrast to published results using the static conditions, we obtained ten times higher corrosion rates. We analyzed the corrosion products with a combination of techniques, like ToF-SIMS, SEM-EDS and FIB-SEM, and found strong evidence that siderite is not the sole corrosion product of Mi-MIC. The corrosion layers contain phosphorus, oxygen, magnesium, calcium and iron and lacked on carbon-related species. It is hypothesized that methanogens may have influenced the nucleation process of siderite, converting bicarbonate into carbon dioxide for methanogenesis. This results in increased localized corrosion and reduced siderite formation. To verify and deepen our understanding of Mi-MIC, we are currently studying the influence of additional environmental parameters (e.g. pH, salinity, flow rate etc.) on Mi-MIC and the subsequent impacts on corrosion rates and the corrosion products. Overall, results of this study will expand the current understanding of MIC from both analytical and mechanistic points of view, thus aiding the development of different mitigation strategies for various industry sectors. T2 - Eurocorr 2021 CY - Online meeting DA - 20.09.2021 KW - Methanogen-induced microbiologically influenced corrosion KW - Carbon steel KW - SEM-EDS KW - Modelling studies PY - 2021 AN - OPUS4-54043 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Selina T1 - Effect of biocides on the evolution and spread of resistance N2 - Biocides used as material preservatives are in contact with various environments during direct application or passive leaching from protected materials [1]. Antimicrobial resistance (AMR) is a global health problem and the environment is an important compartment for the evolution and transmission of AMR [2,3]. Soil is an environment with a large reservoir of natural microbial communities and antimicrobial resistance (AMR) genes. Those natural microbial communities are frequently exposed to biocides used as material preservatives. Previous studies have shown that antibiotics, metals and pesticides affect the underlying processes of resistance evolution and spread; namely de novo mutagenesis and horizontal gene transfer by conjugation and transformation in microbial communities. However, it is unknown if active substances used in material preservatives are involved in these processes. We show that biocides used as material preservatives affect rates of mutation and conjugation in microorganism in a species- and substance-dependent manner, while rates of transformation are not directly affected. Our data highlights the importance of assessing the contribution of material preservatives on AMR evolution and spread in the environment. T2 - RokoCon2022 CY - Berlin, Germany DA - 29.09.2022 KW - Biocide KW - Antimicrobial resistance KW - Tolerance KW - Horizontal gene transfer KW - Mutation rate PY - 2022 AN - OPUS4-56431 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koerdt, Andrea T1 - The impact and potential of halophilic microorganisms on alternative fuels N2 - As more industrial interests focusing on using salt caverns and repurposed gas or petroleum reservoirs for alternative fuel storage, i.e. CO2/H2, the question raises whether microorganisms may impact the infrastructure, gas purity and storage condition over time. Environments with high salinity (> 1.5 Meq of NaCl) are resided by halophiles (salt-loving microorganisms). To compensate for the intensive osmotic stress, they have resorted to two main adaptation strategies: 1) production of compatible solutes and 2) accumulation of intracellular KCl. Microbial community analysis of several high salinity environments revealed a number of recurring genera, including Halomonas and Halanaerobium. However, the impact of halophiles on the overall integrity and stability of the storage facilities remain largely unknown. To evaluate the suitability and stability of saline storage facilities, several model halophilic microorganisms, such as members of Halomonas, will be selected as testing subjects. First, the impact of halophiles on the infrastructure will be determined using an integrative approach by combining a number of techniques, including electrochemistry, TOF-SIMS, SEM/FIB/EDS and FIB-TEM. Second, the abilities of halophiles to alter the fuel composition (i.e. increase/decrease the fractions of H2) will be monitored using gas chromatography by growing them under high pressure. As a result of climate change and the accompanying mandatory shift to renewable energy resources, microorganisms will continue to play an important role in the energy sector, both to their benefit and detriment. Thus, it is important to achieve a certain level of understanding regarding the activities and mechanisms of halophiles prior to large-scaled excursions. T2 - ISMOS-8 CY - Online meeting DA - 07.06.2021 KW - Microbiologically influenced corrosion KW - Hydrogen KW - Gas storage KW - Contamination PY - 2021 AN - OPUS4-52891 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Selection of resistance by antimicrobials used in coatings N2 - Antimicrobial surfaces have broad use in multiple settings including touch surfaces in hospitals, implanted devices, or consumer products. Their aim is to support existing hygiene procedures, and to help combat the increasing threat of antimicrobial resistance. However, concerns have been raised over the potential selection pressure exerted by such surfaces, which might drive the evolution and spread of antimicrobial resistance. In my presentation, I will highlight the risks and knowledge gaps associated with resistance on antimicrobial surfaces by different processes including evolution by de novo mutations and horizontal gene transfer, and species sorting of inherently resistant bacteria dispersed onto antimicrobial surfaces. The latter process has the potential to select for antibiotic resistance via cross-resistance between traits that confer resistance to both the antimicrobial surface coating and antibiotics. Conditions in which antibiotics and antimicrobial coatings are present simultaneously (e.g. implants) will lead to more complex interactions that can either result in the selection for or against antibiotic resistance. We mapped these interactions between several antimicrobials and antibiotics on growth and selection of Pseudomonas aeruginosa. We find prevalent physiological (i.e. synergy and antagonism) and evolutionary (i.e. cross-resistance and collateral sensitivity) combination effects. Understanding these interactions opens the door to tailor therapeutic interventions to select against resistance. In additions, we need new methods and translational studies that investigate resistance development to antimicrobial surfaces under realistic conditions. Therefore, I will present recent developments in our lab on the development of such a method based on existing efficacy standards. T2 - 2021 Fall Meeting of the European Materials Research Society (E-MRS) CY - Online meeting DA - 20.09.2021 KW - Antimicrobial resistance KW - Antimicrobial coating KW - Biofilms KW - Biocides PY - 2021 AN - OPUS4-53645 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Deland, Eric A1 - Kleinbub, Sherin T1 - Is Methanogen-induced microbiologically influenced corrosion (Mi-MIC) underestimated? N2 - The role of methanogens in microbiologically influenced corrosion (Mi-MIC) is often neglected, due to 1) low reported corrosion rates and 2) the suspected corrosion product siderite, which is electrically non-conductive. Typically, MIC corrosion studies are carried out using batch cultures, which did not represent the dynamic conditions, i.e. pipeline and provide insufficient information on the overall corrosion potential. We established a unique approach, a multiport flow column (MFC), to simulate pipeline conditions and obtained 10-times higher corrosion rates than previously published. Our result showed that testing procedures have a large impact on the corrosive potential of methanogens. We found strong indications with a combination of ToF-SIMS, SEM-EDS and FIB-SEM analyses that siderite is not the sole corrosion product. The corrosion layers contain phosphorus, oxygen, magnesium, calcium and iron. To verify and deepen our understanding of Mi-MIC, we are currently studying the influence of other environmental parameters (e.g. pH) on Mi-MIC. T2 - VAAM 2021 CY - Online meeting DA - 18.03.2021 KW - Methanogen-induced microbiologically influenced corrosion KW - Carbon steel KW - MIC Island PY - 2021 AN - OPUS4-54042 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -