TY - JOUR A1 - Vandrich, Jasmina A1 - Pfeiffer, F. A1 - Alfaro Espinoza, Gabriela A1 - Kunte, Hans-Jörg T1 - Contribution of mechanosensitive channels to osmoadaptation and ectoine excretion in Halomonas elongata N2 - For osmoadaptation the halophilic bacterium Halomonas elongata synthesizes as its main compatible solute the aspartate derivative ectoine. H. elongata does not rely entirely on synthesis but can accumulate ectoine by uptake from the surrounding environment with the help of the osmoregulated transporter TeaABC. Disruption of the TeaABC-mediated ectoine uptake creates a strain that is constantly losing ectoine to the medium. However, the efflux mechanism of ectoine in H. elongata is not yet understood. H. elongata possesses four genes encoding mechanosensitive channels all of which belong to the small conductance type (MscS). Analysis by qRT-PCR revealed a reduction in transcription of the mscS genes with increasing salinity. The response of H. elongata to hypo- and hyperosmotic shock never resulted in up-regulation but rather in downregulation of mscS transcription. Deletion of all four mscS genes created a mutant that was unable to cope with hypoosmotic shock. However, the knockout mutant grew significantly faster than the wildtype at high salinity of 2 M NaCl, and most importantly, still exported 80% of the ectoine compared to the wildtype. We thus conclude that a yet unknown system, which is independent of mechanosensitive channels, is the major export route for ectoine in H. elongata. KW - Halomonas elongata KW - Ectoine KW - Osmotic shock KW - Solute excretion KW - Osmoadaptation KW - Mechanosensitive channel KW - MscS PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507229 DO - https://doi.org/10.1007/s00792-020-01168-y VL - 24 SP - 421 EP - 432 PB - Springer AN - OPUS4-50722 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Valentin, Jules D. P. A1 - Altenried, Stefanie A1 - Varadarajan, Adithi R. A1 - Ahrens, Christian H. A1 - Schreiber, Frank A1 - Webb, Jeremy S. A1 - van der Mei, Henny C. A1 - Ren, Qun T1 - Identification of Potential Antimicrobial Targets of Pseudomonas aeruginosa Biofilms through a Novel Screening Approach N2 - Pseudomonas aeruginosa is an opportunistic pathogen of considerable medical importance, owing to its pronounced antibiotic tolerance and association with cystic fibrosis and other life-threatening diseases. The aim of this study was to highlight the genes responsible for P. aeruginosa biofilm tolerance to antibiotics and thereby identify potential new targets for the development of drugs against biofilm-related infections. By developing a novel screening approach and utilizing a public P. aeruginosa transposon insertion library, several biofilm-relevant genes were identified. The Pf phage gene (PA0720) and flagellin gene (fliC) conferred biofilm-specific tolerance to gentamicin. Compared with the reference biofilms, the biofilms formed by PA0720 and fliC mutants were completely eliminated with a 4-fold-lower gentamicin concentration. Furthermore, the mreC, pprB, coxC, and PA3785 genes were demonstrated to play major roles in enhancing biofilm tolerance to gentamicin. The analysis of biofilm-relevant genes performed in this study provides important novel insights into the understanding of P. aeruginosa antibiotic tolerance, which will facilitate the detection of antibiotic resistance and the development of antibiofilm strategies against P. aeruginosa. KW - Antimicrobial resistance KW - Bacteria KW - Biofilms KW - Pseudomonas aeruginosa PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570205 DO - https://doi.org/10.1128/spectrum.03099-22 SP - 1 EP - 5 PB - ASM Journals AN - OPUS4-57020 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Valentin, J. A1 - Straub, H. A1 - Pietsch, Franziska A1 - Lemare, M. A1 - Ahrens, C. A1 - Schreiber, Frank A1 - Webb, J. A1 - van der Mei, H. A1 - Ren, Q. T1 - Role of the flagellar hook in the structural development and antibiotic tolerance of Pseudomonas aeruginosa biofilms N2 - Pseudomonas aeruginosa biofilms exhibit an intrinsic resistance to antibiotics and constitute a considerable clinical threat. In cystic fibrosis, a common feature of biofilms formed by P. aeruginosa in the airway is the occurrence of mutants deficient in flagellar motility. This study investigates the impact of flagellum deletion on the structure and antibiotic tolerance of P. aeruginosa biofilms, and highlights a role for the flagellum in adaptation and cell survival during biofilm development. Mutations in the flagellar hook protein FlgE influence greatly P. aeruginosa biofilm structuring and antibiotic tolerance. Phenotypic analysis of the flgE knockout mutant compared to the wild type (WT) reveal increased fitness under planktonic conditions, reduced initial adhesion but enhanced formation of microcolony aggregates in a microfluidic environment, and decreased expression of genes involved in exopolysaccharide formation. Biofilm cells of the flgE knock-out mutant display enhanced tolerance towards multiple antibiotics, whereas its planktonic cells show similar resistance to the WT. Confocal microscopy of biofilms demonstrates that gentamicin does not affect the viability of cells located in the inner part of the flgE knock-out mutant biofilms due to reduced penetration. These findings suggest that deficiency in flagellar proteins like FlgE in biofilms and in cystic fibrosis infections represent phenotypic and evolutionary adaptations that alter the structure of P. aeruginosa biofilms conferring increased antibiotic tolerance. KW - Antimicrobial resistance KW - Bacteria KW - Biofilms KW - Biocides PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541113 DO - https://doi.org/10.1038/s41396-021-01157-9 SN - 1751-7370 VL - 16 IS - 4 SP - 1176 EP - 1186 PB - Springer Nature AN - OPUS4-54111 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - THES A1 - Usmani, Shirin T1 - Wood treated with nano metal fluorides - relations between composition, size, and durability N2 - In this study, nanoscopic particles of magnesium Fluoride (MgF2) and calcium fluoride (CaF2) also known as nano metal fluorides (NMFs), were evaluated for their potential to improve wood durability. Even though these fluorides are sparingly soluble, their synthesis in the form of nano-sized particles turns them into promising candidates for wood preservation. Their distinct property of low-water solubility is proposed to maintain long-lasting protection of treated wood by reducing the leaching of fluoride. Analytical methods were used to characterize the synthesized NMFs and their distribution in treated wood specimens. Transmission electron microscopy images showed that these fluoride particles are smaller than 10 nm. In nano metal fluoride (NMF) treated specimens, aggregates of these particles are uniformly distributed in the wood matrix as confirmed with scanning electron microscopy images and their corresponding energy-dispersive X-ray spectroscopy maps. The fluoride aggregates form a protective layer around the tracheid walls and block the bordered pits, thus reducing the possible flow path for water absorption into wood. This is reflected in the reduced swelling and increased hydrophobicity of wood treated with NMFs. The biocidal efficacy of NMFs was tested against brown-rot fungi (Coniophora puteanaand Rhodonia placenta), white-rot fungus (Trametes versicolor), and termites (Coptotermes formosanus). The fungal and termite tests were performed in accordance with the EN 113 (1996) and EN 117 (2012) standards, respectively. Prior to fungal tests, the NMF treated wood specimens were leached according to the EN 84 (1997)standard. Compared to untreated specimens, the NMF treated wood specimens have a higher resistance to decay caused by brown-rot fungi, white-rot fungus, and termites. Although all NMF treatments in wood reduce the mass loss caused by fungal decay, only the combined treatment of MgF2 and CaF2 has efficacy against both brown-rot fungi and white-rot fungus. Similarly, wood treated with the combined NMF formulation is the least susceptible to attack by C. formosanus.It is proposed that combining MgF2 and CaF2changes their overall solubility to promote the release of fluoride ions at the optimal concentration needed for biocidal efficacy against fungi and termites. In this thesis, it was proven that even after leaching, sufficient fluoride was present to protect NMF treated wood from fungal decay. This shows that NMFs are robust enough for above ground contact outdoor applications of wood, where permanent wetness cannot be avoided according to Use Class 3.2, as per the EN 335 (2013) standard. Also, they pose a low risk to human health and the environment because they are sparingly soluble. Since NMFs significantly reduce the decay of wood, the CO2 fixed in it will be retained for longer than in unpreserved wood. Overall, the novel results of this study show the potential of NMFs to increase the service life of building materials made from non-durable wood. KW - Termites KW - Nano metal fluorides KW - Solubility KW - Wood protection KW - Fungi PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525108 DO - https://doi.org/10.18452/22553 SP - i EP - 118 PB - Humboldt-Universität zu Berlin CY - Berlin AN - OPUS4-52510 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Usmani, S. A1 - Voss, L. A1 - Stephan, Ina A1 - Hübert, Thomas A1 - Kemnitz, E. T1 - Improved Durability of Wood Treated with Nano Metal Fluorides against Brown-Rot and White-Rot Fungi N2 - Low-water soluble metal fluorides such as magnesium fluoride (MgF2) and calcium Fluoride (CaF2) were evaluated for decay protection of wood. Initially, the biocidal efficacy of nano metal fluorides (NMFs) against wood destroying fungi was assessed with an in-vitro agar test. The results from the test showed that agar medium containing MgF2 and CaF2 was more efficient in preventing fungal decay than stand-alone MgF2 or CaF2. These metal fluorides, in their nanoscopic form synthesized using fluorolytic sol-gel synthesis, were introduced into the sapwood of Scots pine and beech wood and then subjected to accelerated ageing by leaching (EN 84). MAS 19F NMR and X-ray micro CT images showed that metal fluorides were present in treated wood, unleached and leached. Decay resistance of Scots pine and beech wood treated with NMFs was tested against Wood destroying fungi Rhodonia placenta and Trametes versicolor in accordance with EN 113. Results revealed that mass losses were reduced to below 3% in wood treated with the combination of MgF2 and CaF2. It is concluded that NMFs provide full protection to wood even after it has been leached and can be used as wood preservatives in outdoor environments. KW - Nanoparticles KW - Fluoride KW - Wood protection KW - Fluorolytic sol-gel synthesis KW - Brown-rot fungi KW - White-rot fungi KW - Basidiomycetes PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543877 DO - https://doi.org/10.3390/app12031727 VL - 12 IS - 3 SP - 1 EP - 11 PB - MDPI AN - OPUS4-54387 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ulbricht, Alexander T1 - Do Microbes like Additively Manufactured Aluminium? First Details of a Corrosion Test using Sulphate-Reducing Bacteria N2 - Additively manufactured metals become relevant for industrial application. Although many studies on wet corrosion of these metals have been conducted, to the authors knowledge no study seems to contain microbiological corrosion (MIC). In the presented study an experiment was conducted on PBF-LB/AlSi10Mg to test this material's susceptibility for MIC. The tested specimen were analysed using Computed Tomography before and after the MIC experiment to enable a detailed characterisation the damage on the specimens' global and local level. A global reduction of material was observed. In addition, localised damage along process inherent features of the materials microstructure was observed. T2 - Beiratssitzung TF Umwelt CY - Berlin, Germany DA - 17.03.2025 KW - Computed Tomography KW - Additive Manufacturing KW - Biocorrosion KW - Sulphate-reducing Bacteria KW - Microbially influenced corrosion PY - 2025 AN - OPUS4-62772 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ulbricht, Alexander T1 - Do Microbes like Additively Manufactured Aluminium? N2 - The use of laser-additively manufactured metallic components in the industrial sector is gaining traction, with the process now entering its application phase. Consequently, the materials are exposed to corrosive microbes, which this study examines in order to determine the implications of this exposure. Specifically, the study examines the exposure of laser powder bed fused AlSi10Mg (PBF-LB/AlSi10Mg) components to sulphate-reducing bacteria in an anaerobic environment. Is the specific PBF-LB microstructure a potential factor in determining or aiding biocorrosion? A prismatic specimen was exposed to sulphate-reducing bacteria (SRB) for two weeks. The sample was scanned by X-ray computed tomography (XCT) before and after SRB exposure. The two data sets were registered to each other (using the internal void distribution as markers, due to the corrosion of the specimen’s surface) to enable the evaluation of the corrosion damage. Virtual cuts of the 3D XCT reconstructions show a loss of volume and localised damage. The damage distribution aligns with the hatching pattern of laser exposure from laser powder bed fusion. T2 - Konferenz iCT 2026 CY - Linz, Austria DA - 10.02.2026 KW - Computed tomography KW - Biokorrosion KW - Additive manufacturing KW - PBF-LB KW - Laser powder bed fusion KW - Sulphate-reducing bacteria PY - 2026 AN - OPUS4-65570 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tavasolyzadeh, Zeynab A1 - Tang, Peng A1 - Hahn, Marc Benjamin A1 - Hweidi, Gada A1 - Nordholt, Niclas A1 - Haag, Rainer A1 - Sturm, Heinz A1 - Topolniak, Ievgeniia T1 - 2D and 3D Micropatterning of Mussel‐Inspired Functional Materials by Direct Laser Writing N2 - AbstractThis work addresses the critical need for multifunctional materials and substrate‐independent high‐precision surface modification techniques that are essential for advancing microdevices and sensing elements. To overcome existing limitations, the versatility of mussel‐inspired materials (MIMs) is combined with state‐of‐the‐art multiphoton direct laser writing (DLW) microfabrication. In this way, 2D and 3D MIM microstructures of complex designs are demonstrated with sub‐micron to micron resolution and extensive post‐functionalization capabilities. This study includes polydopamine (PDA), mussel‐inspired linear, and dendritic polyglycerols (MI‐lPG and MI‐dPG), allowing their direct microstructure on the substrate of choice with the option to tailor the patterned topography and morphology in a controllable manner. The functionality potential of MIMs is demonstrated by successfully immobilizing and detecting single‐stranded DNA on MIM micropattern and nanoarray surfaces. In addition, easy modification of MIM microstructure with silver nanoparticles without the need of any reducing agent is shown. The methodology developed here enables the integration of MIMs in advanced applications where precise surface functionalization is essential. KW - Direct laser writing KW - Mussel-inspired materials KW - Polyglycerol KW - Polydopamine KW - Micropatterning PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588778 DO - https://doi.org/10.1002/smll.202309394 SN - 1613-6829 SP - 1 EP - 12 PB - Wiley-VCH CY - Weinheim AN - OPUS4-58877 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Taghavi Kalajahi, Sara A1 - Misra, Archismita A1 - Koerdt, Andrea T1 - Nanotechnology to mitigate microbiologically influenced corrosion (MIC) N2 - Microbiologically influenced corrosion (MIC) is a crucial issue for industry and infrastructure. Biofilms are known to form on different kinds of surfaces such as metal, concrete, and medical equipment. However, in some cases the effect of microorganisms on the material can be negative for the consistency and integrity of the material. Thus, to overcome the issues raised by MIC on a system, different physical, chemical, and biological strategies have been considered; all having their own advantages, limitations, and sometimes even unwanted disadvantages. Among all the methods, biocide treatments and antifouling coatings are more common for controlling MIC, though they face some challenges. They lack specificity for MIC microorganisms, leading to cross-resistance and requiring higher concentrations. Moreover, they pose environmental risks and harm non-target organisms. Hence, the demand for eco-friendly, long-term solutions is increasing as regulations tighten. Recently, attentions have been directed to the application of nanomaterials to mitigate or control MIC due to their significant antimicrobial efficiency and their potential for lower environmental risk compared to the conventional biocides or coatings. Use of nanomaterials to inhibit MIC is very new and there is a lack of literature review on this topic. To address this issue, we present a review of the nanomaterials examined as a biocide or in a form of a coating on a surface to mitigate MIC. This review will help consolidate the existing knowledge and research on the use of nanomaterials for MIC mitigation. It will further contribute to a better understanding of the potential applications and challenges associated with using nanomaterials for MIC prevention and control. KW - Microbiologically influenced corrosion (MIC) KW - Biofilm KW - Biofouling KW - Nanobiocide KW - Nanocoating PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599335 DO - https://doi.org/10.3389/fnano.2024.1340352 SN - 2673-3013 VL - 6 SP - 1 EP - 25 PB - Frontiers Media CY - Lausanne AN - OPUS4-59933 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Taghavi Kalajahi, Sara T1 - The effectiveness of cathodic protection (CP) on microbiologically influenced corrosion (MIC) control N2 - Cathodic protection (CP) is an electrochemical method, to manage corrosion in different industries, especially in buried and sub-merged environments. In those environments microorganisms are present and can affect the corrosion process and cause microbiologically influenced corrosion (MIC). Most of the industry standards recommend performing CP using -800 mV (Ag/AgCl), however, if microorganisms capable of initiating MIC are present, for instance sulfate reducing bacteria (SRB), it is recommended to use even more negative potentials. It is assumed that this will provide adequate protection of the metal. Currently there is no information or valid data in the context of CP, on the level of MIC threat and the extent to which more negative potentials can be used to provide adequate protection and not over-protection (due to hydrogen embrittlement threat). Conflicting statements can be found in the literature regarding the effectiveness of CP on MIC, from reducing biofilm attachment to increasing bacterial activity and biofilm attachment. Recently, the development and lower price of molecular microbiological methods (MMM) have opened the door for more effective studies of MIC mechanisms along with other electrochemical methods and surface analysis. In this work, the genetic functionality of biofilms formed in the laboratory under CP conditions is investigated using transcriptomics. Gene expression of SRB biofilms under different CP potentials (-800, -850 and -900 mV) will be studied; comparison with control will allow us to distinguish the specific genes that are differentially expressed, leading to a better understanding of the mechanism of CP to affect bacterial activity and diversity. Keywords - cathodic protection, microbiologically influenced corrosion, molecular microbial methods. T2 - IBBS CY - Berlin, Germany DA - 09.09.2024 KW - Microbiologically influenced corrosion PY - 2024 AN - OPUS4-61981 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stephan, Ina A1 - Dimke, Thomas A1 - Guterman, R. A1 - Smith, C. A. A1 - Cataldo, V. A. T1 - Antibacterial and degradable thioimidazolium poly(ionic liquid) N2 - New antibacterial agents are urgently required to fight the emergence of antibiotic-resistant bacteria. We recently synthesized the first thioimidazolium ionene, which has antibacterial properties and can degrade in various media. This dual functionality is crucial in order to limit the environmental impact of these biocides. We have found that our polymer is stronger than benzalkonium chloride (BAC) against Pseudomonas aeruginosa and also readily degrades in the presence of base, while remaining stable in acidic environments. These results highlight a new emerging class of antibacterial degradable polymers. KW - Ionic liquid KW - Antibacterial polymer KW - Amphiphilic polymer KW - Thioimidazolium KW - Degradable polymer KW - Polyioinic liquid PY - 2020 DO - https://doi.org/10.1021/acssuschemeng.0c02666 VL - 8 IS - 22 SP - 8419 EP - 8424 PB - ACS Publications AN - OPUS4-50982 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Srivastava, Priyanka A1 - Tavernaro, Isabella A1 - Scholtz, Lena A1 - Genger, C. A1 - Welker, P. A1 - Schreiber, Frank A1 - Meyer, Klas A1 - Resch-Genger, Ute T1 - Dual color pH probes made from silica and polystyrene nanoparticles and their performance in cell studies N2 - Ratiometric green–red fluorescent nanosensors for fluorometrically monitoring pH in the acidic range were designed from 80 nm-sized polystyrene (PS) and silica (SiO2) nanoparticles (NPs), red emissive reference dyes, and a green emissive naphthalimide pH probe, analytically and spectroscopically characterized, and compared regarding their sensing performance in aqueous dispersion and in cellular uptake studies. Preparation of these optical probes, which are excitable by 405 nm laser or LED light sources, involved the encapsulation of the pH-inert red-fuorescent dye Nile Red (NR) in the core of self-made carboxylated PSNPs by a simple swelling procedure and the fabrication of rhodamine B (RhB)-stained SiO2-NPs from a silane derivative of pH-insensitive RhB. Subsequently, the custom-made naphthalimide pH probe, that utilizes a protonation-controlled photoinduced electron transfer process, was covalently attached to the carboxylic acid groups at the surface of both types of NPs. Fluorescence microscopy studies with the molecular and nanoscale optical probes and A549 lung cancer cells confirmed the cellular uptake of all probes and their penetration into acidic cell compartments, i.e., the lysosomes, indicated by the switching ON of the green naphthalimide fluorescence. This underlines their suitability for intracellular pH sensing, with the SiO2-based nanosensor revealing the best performance regarding uptake speed and stability. KW - Sensors KW - Silica and polystyrene nanoparticles KW - pH probe KW - Fluorescence spectroscopy KW - Cell studies KW - Dye KW - Particle synthesis PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569198 DO - https://doi.org/10.1038/s41598-023-28203-0 SN - 2045-2322 VL - 13 IS - 1 SP - 1321 EP - 1336 PB - Nature CY - London AN - OPUS4-56919 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sobisch, Lydia-Yasmin T1 - Time-kill kinetics reveal heterogeneous tolerance to disinfectants N2 - Background. Disinfection is an important mitigation strategy to control and prevent the spread of infections. Incomplete or incorrect usage of disinfection may promote evolution of resistance against disinfectants and antibiotics. Ideally, disinfection reduces the number of surviving bacteria and the chance for resistance evolution. Resistance describes the ability to grow in previously inhibitory concentrations of an antimicrobial, whereas tolerance is associated with enhanced survival of lethal doses. Individual bacteria from the same population can display considerable heterogeneity in their ability to survive treatment (i.e. tolerance) with antimicrobials, which can result in unexpected treatment failure. Objective. In this study, we investigated six active substances of disinfectants, preservatives, and antiseptics against a population of E. coli to identify the presence of a tolerant subpopulation. Methods. We performed time-kill experiments and analyzed the data with a mathematical model to statistically infer whether the data is best explained by the presence of a tolerant subpopulation. Results. The analysis identified bimodal kill kinetics for benzalkonium chloride, didecyldimethylammonium chloride, and isopropanol. In contrast, kill kinetics by chlorhexidine, glutaraldehyde, and hydrogen peroxide were best explained by unimodal kill kinetics. These findings have implications for the risk of disinfection failure. In addition, we are currently performing adaptive laboratory evolution (ALE) experiments with the different disinfectants to investigate the potential consequences of tolerant sub-populations for the evolution of antimicrobial resistance and tolerance. T2 - FEMS Conference CY - Hamburg, Germany DA - 10.07.2023 KW - Biocide KW - Desinfectant KW - E.coli PY - 2023 AN - OPUS4-58471 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 - Sobisch, Lydia-Yasmin T1 - Time-kill kinetics reveal heterogeneous tolerance to disinfectants N2 - Background. Disinfection is an important mitigation strategy to control and prevent the spread of infections. Incomplete or incorrect usage of disinfection may promote evolution of resistance against disinfectants and antibiotics. Ideally, disinfection reduces the number of surviving bacteria and the chance for resistance evolution. Resistance describes the ability to grow in previously inhibitory concentrations of an antimicrobial, whereas tolerance is associated with enhanced survival of lethal doses. Individual bacteria from the same population can display considerable heterogeneity in their ability to survive treatment (i.e. tolerance) with antimicrobials, which can result in unexpected treatment failure. Objective. In this study, we investigated six active substances of disinfectants, preservatives, and antiseptics against a population of E. coli to identify the presence of a tolerant subpopulation. Methods. We performed time-kill experiments and analyzed the data with a mathematical model to statistically infer whether the data is best explained by the presence of a tolerant subpopulation. Results. The analysis identified bimodal kill kinetics for benzalkonium chloride, didecyldimethylammonium chloride, and isopropanol. In contrast, kill kinetics by chlorhexidine, glutaraldehyde, and hydrogen peroxide were best explained by unimodal kill kinetics. These findings have implications for the risk of disinfection failure. In addition, we are currently performing adaptive laboratory evolution (ALE) experiments with the different disinfectants to investigate the potential consequences of tolerant sub-populations for the evolution of antimicrobial resistance and tolerance. T2 - Vereinigung Allgemeiner und Angewandter Mikrobiobiologie Jahreskongress 2023 CY - Göttingen, Germany DA - 10.09.2023 KW - Biocide KW - Desinfectant KW - E.coli PY - 2023 AN - OPUS4-58470 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schwibbert, Karin A1 - Richter, Anja A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Laser-Textured Surfaces: A Way to Control Biofilm Formation? N2 - Bacterial biofilms pose serious problems in medical and industrial settings. One of the major societal challenges lies in the increasing resistance of bacteria against biocides used in antimicrobial treatments, e.g., via overabundant use in medicine, industry, and agriculture or cleaning and disinfection in private households. Hence, new efficient bacteria-repellent strategies avoiding the use of biocides are strongly desired. One promising route to achieve bacteria-repellent surfaces lies in the contactless and aseptic large-area laser-processing of technical surfaces. Tailored surface textures, enabled by different laser-processing strategies that result in topographic scales ranging from nanometers to micrometers may provide a solution to this challenge. This article presents a current state-of-the-art review of laser-surface subtractive texturing approaches for controlling the biofilm formation for different bacterial strains and in different environments. Based on specific properties of bacteria and laser-processed surfaces, the challenges of anti-microbial surface designs are discussed, and future directions will be outlined. KW - Antibacterial surfaces KW - Biofilms KW - Laser processing KW - Laser-induced periodic surface structures (LIPSS) KW - Microbial adhesions PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588260 DO - https://doi.org/10.1002/lpor.202300753 SN - 1863-8899 SP - 1 EP - 41 PB - Wiley-VCH GmbH CY - Weinheim AN - OPUS4-58826 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - VIDEO A1 - Schwibbert, Karin A1 - Richter, Anja A1 - Bonse, Jörn T1 - BioCombs4Nanofibers: From nanofibers over spiders to bacteria N2 - This 6 minute long MP4-video presents some key results of the European research project "BioCombs4Nanofibers" to the broader public. Inspired by nature, some concepts of certain types of spiders are transferred to technology in order to develop bacteria-repellent surfaces through laser surface nanostructuring. Funding notice: This study was funded by the European Union's research and innovation program under the FET Open grant agreement No. 862016 (BioCombs4Nanofibers, http://biocombs4nanofibers.eu). KW - Antiadhesive surfaces KW - Laser-induced periodic surface structures (LIPSS) KW - Cribellate spiders KW - Bacterial adhesion tests KW - Bacteria-repellent surfaces PY - 2022 UR - https://download.jku.at/org/7kM/xyU/BioCombs4Nanofibers/D5.6_video%20for%20the%20broader%20public_23.03.2022.mp4 UR - https://www.jku.at/en/biocombs4nanofibers/dissemination/ DO - https://doi.org/10.26272/opus4-54939 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-54939 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schwibbert, Karin A1 - de Eulate Pérez, Elisa García A1 - Wen, Keqing A1 - Voss, Heike A1 - Thiele, Dorothea A1 - Richter, Anja M. A1 - Bonse, Jörn T1 - Escherichia coli repellence via laser-induced periodic surface structures (LIPSS) on titanium: Critical role of biofilm-associated gene expression N2 - The inconsistency in the observed bacteria-repellent effects of laser-induced surface textures remains a subject of scientific debates. With E. coli TG1 as test strain, we performed biofilm formation assays on ultrashort pulse laser textured titanium. Samples covered with low spatial frequency LIPSS (LSFL) of periods around 750 nm or with high spatial frequency LIPSS (HSFL) featuring smaller periods around 100 nm were processed on polished samples. While LSFL significantly reduce the number of adhering bacteria compared to the polished reference, HSFL do not. Simultaneously, we concentrate our study on bacterial strategies employed for biofilm formation, that is the transcription of the biofilm-associated genes csgB, involved in primary adhesion to a surface, and wza, participating in biofilm maturation. Promoter regions of these genes were cloned into a promotor probe plasmid with the green fluorescent protein GFP+ as reporter and transferred into the test strain. As indicated by the fluorescence intensity of the reporter protein, among the bacteria colonizing LSFL-covered areas, a markedly higher proportion of cells transcribing csgB or wza were detected, compared to the bacterial populations colonizing the polished or HSFL-covered areas. To our knowledge, this is the first study indicating that the antifouling effect of LSFL topographies can be counteracted when bacteria activate biofilm-associated genes. KW - Laser-induced periodic surface structures (LIPSS) KW - Titanium KW - Biofilm KW - Antifouling KW - Gene expression KW - Fluorescence microscopy PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655572 DO - https://doi.org/10.1016/j.apsusc.2026.166363 SN - 0169-4332 VL - 730 SP - 1 EP - 9 PB - Elsevier B.V. AN - OPUS4-65557 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schulze-Makuch, D. A1 - Lipus, D. A1 - Arens, F. L. A1 - Baque, M. A1 - Bornemann, T. L. V. A1 - de Vera, J. P. A1 - Flury, M. A1 - Froesler, J. A1 - Heinz, J. A1 - Hwang, Y. A1 - Kounaves, S. P. A1 - Mangelsdorf, K. A1 - Meckenstock, R. U. A1 - Pannekens, M. A1 - Probst, A. J. A1 - Saenz, J. S. A1 - Schirmack, J. A1 - Schloter, M. A1 - Schmitt-Kopplin, P. A1 - Schneider, Beate A1 - Uhl, J. A1 - Vestergaard, G. A1 - Valenzuela, B. A1 - Zamorano, P. A1 - Wagner, D. T1 - Microbial hotspots in lithic microhabitats inferred from DNA fractionation and metagenomics in the Atacama Desert N2 - The existence of microbial activity hotspots in temperate regions of Earth is driven by soil heterogeneities, especially the temporal and spatial availability of nutrients. Here we investigate whether microbial activity hotspots also exist in lithic microhabitats in one of the most arid regions of the world, the Atacama Desert in Chile. While previous studies evaluated the total DNA fraction to elucidate the microbial communities, we here for the first time use a DNA separation approach on lithic microhabitats, together with metagenomics and other analysis methods (i.e., ATP, PLFA, and metabolite analysis) to specifically gain insights on the living and potentially active microbial community. Our results show that hypolith colonized rocks are microbial hotspots in the desert environment. In contrast, our data do not support such a conclusion for gypsum crust and salt rock environments, because only limited microbial activity could be observed. The hypolith community is dominated by phototrophs, mostly Cyanobacteria and Chloroflexi, at both study sites. The gypsum crusts are dominated by methylotrophs and heterotrophic phototrophs, mostly Chloroflexi, and the salt rocks (halite nodules) by phototrophic and halotolerant endoliths, mostly Cyanobacteria and Archaea. The major environmental constraints in the organic-poor arid and hyperarid Atacama Desert are water availability and UV irradiation, allowing phototrophs and other extremophiles to play a key role in desert ecology. KW - Desert ecology KW - Extremophile KW - Hyperarid PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527959 DO - https://doi.org/10.3390/microorganisms9051038 SN - 2076-2607 VL - 9 IS - 5 SP - 1038 PB - MDPI CY - Basel AN - OPUS4-52795 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schulze-Makuch, D. A1 - Haque, S. A1 - Beckles, D. A1 - Schmitt-Kopplin, P. A1 - Harir, M. A1 - Schneider, Beate A1 - Stumpp, C. A1 - Wagner, D. T1 - A chemical and microbial characterization of selected mud volcanoes in Trinidad reveals pathogens introduced by surface water and rain water N2 - Terrestrial mud volcanoes are unique structures driven by tectonic pressure and fluids from the deep subsurface. These structures are mainly found in active tectonic zones, such as the area near the Los Bajos Fault in Trinidad. Here we report a chemical and microbiological characterization of three mud volcanoes, which included analyses of multiple liquid and solid samples from the mud volcanoes. Our study confirms previous suggestions that at least some of the mud volcano fluids are a mixture of deeper salt-rich water and surficial/precipitation water. No apparent water quality differences were found between sampling sites north and south of a major geological fault line. Microbiological analyses revealed diverse communities, both aerobic and anaerobic, including sulfate reducers, methanogens, carbon dioxide fixing and denitrifying bacteria. Several identified species were halophilic and likely derived from the deeper salt-rich subsurface water, while we also cultivated pathogenic species from the Vibrionaceae, Enterobacteriaceae, Shewanellaceae, and Clostridiaceae. These microorganisms were likely introduced into the mud volcano fluids both from surface water or shallow ground-water, and perhaps to a more minor degree by rain water. The identified pathogens are a major health concern that needs to be addressed. KW - Water stable isotope analysis KW - Mud volcanoe fluids KW - Metabolomics PY - 2020 DO - https://doi.org/10.1016/j.scitotenv.2019.136087 VL - 707 SP - 136087 PB - Elsevier B.V. AN - OPUS4-50499 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schulz, Anne-Christine T1 - Co-selection for biocide and antibiotic resistance in microbial wastewater communities N2 - Biocides are used for a wide range of purposes, including disinfectants or preservatives. They play a major role in the prevention of microbial infections in healthcare and animal husbandry. The use of biocides often leads to the discharge of active biocidal substances into wastewater streams, causing the exposure of wastewater microbial communities to subinhibitory concentrations. In turn, it is known that wastewater treatment plants (WWTP) are hotspots for antibiotic resistant bacteria. Since similar mechanisms confer resistance to biocides and antibiotics, exposure to biocides can result in co-selection of antibiotic resistant bacteria in WWTP Here, we want to investigate co-selection processes of antibiotic resistance in natural WWTP microbial communities upon biocide exposure. Microbial communities were sampled at the WWTP Ruhleben in Berlin and characterized regarding their susceptibility against different clinically relevant antibiotics. To investigate the link between biocide exposure and antibiotic resistance, changes in the susceptibility level after exposure to environmentally relevant concentrations of the commonly used biocide didecyldimethylammonium chloride (DDAC) will be determined by enumerating resistant and non-resistant E. coli on selective plates with and without antibiotics and DDAC. In case of antibiotics, clinical breakpoint concentrations according to EUCAST will be used to discriminate between susceptible and resistant strains. In case of DDAC (and biocides in general), clinical breakpoints do not exist. Therefore, we determined a cut-off concentration at which the majority of naturally-occurring E. coli strains cannot grow anymore based on (I) the MIC (minimal inhibitory concentration) distribution, and (II) by plating wastewater communities onto selective indicator agar plates loaded with increasing DDAC concentration. Additionally, antibiotic cross-resistance will be determined by spotting single colonies, isolated from DDAC-selective plates onto antibiotic plates. The results of our experiments will help to determine selective concentrations and to estimate the risk of antibiotic co-selection and cross-resistance in microbial WWTP communities upon biocide exposure. T2 - Annual Conference 2023 of the Association for General and Applied Microbiology CY - Göttingen, Germany DA - 10.09.2023 KW - Antibiotic resisitance KW - Biocide KW - Wastewater KW - Risk assesment PY - 2023 AN - OPUS4-58510 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schulz, Anne-Christine T1 - Assessing co-selection of biocide and antibiotic resistance in wastewater microbial communities N2 - Biocides are used for a wide range of purposes, including disinfectants or preservatives. Biocides play a major role in the prevention of microbial infections in healthcare and animal husbandry. The use of biocides often leads to the discharge of active biocidal substances into wastewater streams, causing the exposure of wastewater microbial communities to subinhibitory concentrations. In turn, it is known that wastewater treatment plants (WWTP) are hotspots for antibiotic resistant bacteria. Since similar mechanisms confer resistance to biocides and antibiotics, exposure to biocides can result in co-selection of antibiotic resistant bacteria in WWTP due to biocides. Here, we investigate the magnitude and the drivers of co-selection of antibiotic resistance in natural wastewater microbial communities upon biocide exposure. Microbial communities will be sampled at the WWTP Ruhleben in Berlin and characterized regarding their biocide and antibiotic resistance. Changes in the resistance level after exposure to different biocides will be determined by enumerating resistant and non-resistant E. coli and heterotrophic bacteria on selective plates with and without several biocides and antibiotics. Moreover, we are establishing a synthetic community comprising about 100 environmental E. coli isolates each with different antimicrobial resistance traits. Each isolate will be tagged with a unique DNA-barcode. All isolates will be pooled and exposed to different biocides at various concentrations. The barcode labeling enables us to determine the abundance of each isolate at the beginning and end of the experiment by transposon-tag sequencing. The project results will inform risk assessment of the effects of biocidal residues on antimicrobial resistance selection in WWTP. The project is part of the BIOCIDE consortium funded within the call on Aquatic pollutants by JPI-AMR, JPI-OCEANS and JPI-WATER. T2 - 6th International Symposium onn the Environmental Dimension of Antibiotic Resistance - EDAR 6 CY - Gothenburg, Sweden DA - 22.09.2022 KW - Antibiotic resisitance KW - Biocide KW - Wastewater KW - Risk assesment PY - 2022 AN - OPUS4-56796 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Schreiber, Frank A1 - Nordholt, Niclas A1 - Lewerenz, Dominique T1 - Time-kill kinetics reveal heterogeneous tolerance to disinfectants N2 - Disinfection is an important strategy to limit the spread of infections. Failure of disinfection may facilitate evolution of resistance against disinfectants and antibiotics through the processes of cross-resistance and co-resistance. The best possible outcome of disinfection minimizes the number of surviving bacteria and the chance for resistance evolution. Resistance describes the ability to grow in previously inhibitory concentrations of an antimicrobial, whereas tolerance is associated with enhanced survival of lethal doses. Individual bacteria from the same population can display considerable heterogeneity in their ability to survive treatment (i.e. tolerance) with antimicrobials, which can result in unexpected treatment failure. Here, we investigated how phenotypic heterogeneity affects the ability of E. coli to survive treatment with six different substances commonly used as active substances in disinfectants, preservatives and antiseptics. A mathematical model which assumes that phenotypic heterogeneity underlies the observed disinfection kinetics was used to infer whether time-kill kinetics were caused by a tolerant subpopulation. The analysis identified bimodal kill kinetics for benzalkonium chloride (BAC), didecyldimethylammonium chloride (DDAC), and isopropanol (Iso). In contrast, kill kinetics by chlorhexidine (CHX), glutaraldehyde (GTA), and hydrogen peroxide (H2O2) were best explained by unimodal kill kinetics underpinned by a broad distribution of tolerance times for CHX as opposed to a narrow distribution of tolerance times for GTA and H2O2. These findings have implications for the risk of disinfection failure, with potential consequences for the evolution of antimicrobial resistance and tolerance. KW - Antimicrobial resistance KW - Bacteria KW - Standardization KW - Biocides PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615572 DO - https://doi.org/https://doi.org/10.1101/2022.06.22.497202 SN - 2692-8205 SP - 1 EP - 20 PB - Cold Spring Harbor Laboratory CY - Cold Spring Harbor, NY AN - OPUS4-61557 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank A1 - Nordholt, Niclas T1 - Persistence against benzalkonium chloride promotes rapid evolution of tolerance under periodic disinfection N2 - Biocides used as disinfectants are important to prevent the transmission of pathogens, especially during the current antibiotic resistance crisis. This crisis is exacerbated by phenotypically tolerant persister subpopulations which can survive transient antibiotic treatment and facilitate resistance evolution. Despite the transient nature of disinfection, knowledge concerning persistence to disinfectants and its link to resistance evolution is currently lacking. Here, we show that E. coli displays persistence against a widely used disinfectant benzalkonium chloride (BAC). Periodic, persister-mediated failure of disinfection rapidly selects for BAC tolerance. BAC tolerance is associated with reduced cell surface charge and mutations in the novel tolerance locus lpxM. Moreover, the fitness cost incurred by BAC tolerance turned into a fitness benefit in the presence of antibiotics, suggesting a selective advantage of BAC-tolerant mutants in antibiotic environments. Our findings provide a mechanistic underpinning for the faithful application of disinfectants to prevent multi-drug-resistance evolution and to steward the efficacy of biocides and antibiotics. T2 - New Approaches and Concepts in Microbiology CY - Online meeting DA - 07.07.2021 KW - Persistence KW - Biocides KW - Evolution KW - Cross-resistance KW - Biocide tolerance PY - 2021 AN - OPUS4-53168 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Schreiber, Frank A1 - Kanaris, Orestis A1 - Nordholt, Niclas T1 - Consequences of benzalkonium chloride tolerance for selection dynamics and de novode novo resistance evolution driven by antibiotics N2 - Biocides are used in large amounts in industrial, medical, and domestic settings. Benzalkonium chloride (BAC) is a commonly used biocide, for which previous research revealed that Escherichia coli can rapidly adapt to tolerate BAC-disinfection, with consequences for antibiotic susceptibility. However, the consequences of BAC- tolerance for selection dynamics and resistance evolution to antibiotics remain unknown. Here, we investigated the effect of BAC -tolerance in E. coli on its response upon challenge with different antibiotics. Competition assays showed that subinhibitory concentrations of ciprofloxacin—but not ampicillin, colistin and gentamicin—select for the BAC-tolerant strain over the BAC-sensitive ancestor at a minimal selective concentration of 0.0013–0.0022 µg∙mL−1. In contrast, the BAC-sensitive ancestor was more likely to evolve resistance to ciprofloxacin, colistin and gentamicin than the BAC-tolerant strain when adapted to higher concentrations of antibiotics in a serial transfer laboratory evolution experiment. The observed difference in the evolvability of resistance to ciprofloxacin was partly explained by an epistatic interaction between the mutations conferring BAC -tolerance and a knockout mutation in ompF encoding for the outer membrane porin F. Taken together, these findings suggest that BAC -tolerance can be stabilized in environments containing low concentrations of ciprofloxacin, while it also constrains evolutionary pathways towards antibiotic resistance. KW - Antimicrobial surfaces KW - Biocides KW - Antimicrobial resistance KW - Antibiotics PY - 2025 UR - https://www.ncbi.nlm.nih.gov/bioproject/?term=PRJNA1282584 PB - National Library of Medicine CY - Bethesda AN - OPUS4-65221 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Biocide Resistance - Road to Risk Assessment N2 - This presentation details the current status of biocide resistance risk assessment and provides a roadmap for future activities. T2 - OECD, 6th Meeting of the Working Party on Biocides CY - Paris, France DA - 28.09.2022 KW - Antimicrobial resistance KW - Antimicrobial coating KW - Standardization KW - Biocides KW - Risk assessment PY - 2022 AN - OPUS4-56263 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - How to regulate and assess resistance risks of co-selecting agents during application and in the environment N2 - This talk deals with the question on How to regulate and assess resistance risks of co-selecting agents during application and in the environment. It shows that there the overview of worldwide activities to regulate co-selecting agents is missing. Regulations for product authorization usually consider resistance in target organisms, but there is a risk of emergence of resistance from non-target organisms as well. Moreover, pollution effects on resistance development in the environment are not explicitly covered during product authorization and few risk assessment schemes and methods available. T2 - EDAR7 - Environmental Dimension of Antimicrobial Resistance Conference 2024 CY - Montreal, Canada DA - 26.05.2024 KW - Antimicrobial resistance KW - Bacteria KW - Standardization KW - Biocides PY - 2024 AN - OPUS4-61542 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Development of a laboratory method to assess resistance development of microorganisms to biocides – An update N2 - This presentation describes the development of a laboratory method to assess resistance development of microorganisms to biocides and antimicrobial surfaces. T2 - The International Biodeterioration Research Group (IBRG) autumn meeting 2022 CY - Online meeting DA - 11.10.2022 KW - Antimicrobial resistance KW - Antimicrobial coating KW - Standardization KW - Biocides KW - Risk assessment PY - 2022 AN - OPUS4-56264 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Development of a laboratory method to assess resistance development of microorganisms to biocides – An update N2 - This presentation describes our efforts at BAM towards the development of a laboratory method to assess resistance development of microorganisms to biocides. T2 - The International Biodeterioration Research Group (IBRG) spring meeting 2023 CY - Online meeting DA - 05.03.2023 KW - Antimicrobial resistance KW - Antimicrobial coating KW - Standardization KW - Biocides PY - 2023 AN - OPUS4-57858 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Development of a laboratory method to assess resistance development of microorganisms to biocides N2 - Bacteria are exposed to biocides through surface disinfection or by antimicrobial surfaces. These stressful environments provide a strong selective pressure for bacteria to adapt. Here, we describe the development of a laboratory method to assess adaption of bacteria by resistance development in response to surface disinfection and antimicrobial surfaces. T2 - OECD, 5th Meeting of the Working Party on Biocides CY - Online meeting DA - 26.05.2021 KW - Antimicrobial resistance KW - Antimicrobial coating KW - Standardization PY - 2021 AN - OPUS4-53163 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Development of a laboratory method to assess resistance development of microorganisms to biocides N2 - Bacteria are exposed to biocides through surface disinfection or by antimicrobial surfaces. These stressful environments provide a strong selective pressure for bacteria to adapt. Here, we describe the development of a laboratory method to assess adaption of bacteria by resistance development in response to surface disinfection and antimicrobial surfaces. T2 - The International Biodeterioration Research Group (IBRG) Spring Meeting 2021 CY - Online meeting DA - 28.06.2021 KW - Antimicrobial resistance KW - Antimicrobial coating KW - Standardization PY - 2021 AN - OPUS4-53164 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 - 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 - 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 - 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 - Schreiber, Frank T1 - Phenotypic and evolutionary responses of bacteria to disinfection N2 - Disinfectants are important to prevent the transmission of pathogens, especially in the face of the current antibiotic resistance crisis. The crisis is further exacerbated by phenotypically tolerant persister subpopulations that can survive transient antibiotic treatment and facilitate resistance evolution. Despite the transient nature of disinfectant application, persistence to disinfectants and its role for the evolution of tolerance and cross-resistance to antibiotics has not been studied. Our work shows that E. coli displays persistence against several widely used disinfectants, including benzalkonium chloride (BAC), didecyldimethylammoniumchlorid (DDAC) and isopropanol. The molecular mechanism of BAC persistence is triggered in stationary phase and affected by several antibiotic persister genes (hipA, tisB, tolC, relA, spoT). Experimental evolution and population dynamic modeling show that repeated failure of disinfection due to persisters rapidly selects for BAC tolerance underpinned by reduced cell surface charge due to mutations in genes related to lipid A acylation (lpxML). Furthermore, evolved BAC tolerance affects the susceptibility to antibiotics, leading to positive selection of disinfectant tolerant strains at environmentally relevant antibiotic concentrations and variations in evolvability of antibiotic resistance due to epistatic effects. These results highlight the need for faithful application of disinfectants to steward their efficacy and the efficacy of antibiotics. A better understanding of the bacterial response to disinfectants is crucial to understand and avert the ongoing antimicrobial resistance crisis. T2 - Gordon Research Conference - Molecular mechanisms of evolution CY - Easton, MA, United States DA - 25.06.2023 KW - Antimicrobial resistance KW - Bacteria KW - Disinfection KW - Biocides PY - 2023 AN - OPUS4-57861 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 - 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 - 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 - ASM-FEMS World Microbe Forum CY - Online meeting DA - 20.06.2021 KW - Antimicrobial resistance KW - Antagonism KW - Biofilms PY - 2021 AN - OPUS4-53165 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 - GEN A1 - Schreiber, Frank T1 - Differential selection for survival and for growth in adaptive laboratory evolution experiments with benzalkonium chloride N2 - Biocides are used to control microorganisms across different applications, but emerging resistance may pose risks for those applications. Resistance to biocides has commonly been studied using adaptive laboratory evolution (ALE) experiments with growth at subinhibitory concentrations linked to serial subculturing. It has been shown recently that E. coli adapts to repeated lethal stress imposed by the biocide benzalkonium chloride (BAC) by increased survival (i.e. tolerance) and not by evolving the ability to grow at increased concentrations (i.e. resistance). Here, we investigate the contributions of evolution for tolerance as opposed to resistance for the outcome of ALE experiments with E. coli exposed to BAC. We find that BAC concentrations close to the half maximal effective concentration (EC50, 4.36 µg mL-1) show initial killing (~40%) before the population resumes growth. This indicates that cells face a two-fold selection pressure: for increased survival and for increased growth. To disentangle the effects of both selection pressures, we conducted two ALE experiments: (i) one with initial killing and continued stress close to the EC50 during growth and (ii) another with initial killing and no stress during growth. Phenotypic characterization of adapted populations showed that growth at higher BAC concentrations was only selected for when BAC was present during growth. Whole genome sequencing revealed distinct differences in mutated genes across treatments. Treatments selecting solely for survival led to mutations in genes for metabolic regulation (cyaA) and cellular structure (flagella fliJ), while treatments selecting for growth and survival led to mutations in genes related to stress response (hslO and tufA). Our results demonstrate that serial subculture ALE experiments with an antimicrobial at sub-inhibitory concentrations can select for increased growth and survival. This finding has implications for the design of ALE experiments to assess resistance risks of antimicrobials in different scenarios such as disinfection, preservation, and environmental pollution. KW - Antimicrobial resistance KW - Bacteria KW - Standardization KW - Biocides PY - 2024 UR - https://www.ncbi.nlm.nih.gov/bioproject/PRJNA1074740 PB - National Library of Biotechnology Information CY - Bethesda AN - OPUS4-61559 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -