TY - CONF A1 - Nordholt, Niclas A1 - Lewerenz, Dominique A1 - Schmidt, Selina A1 - Schreiber, Frank T1 - Heterogeneity in the bacterial response to disinfection and its impact on antibiotic tolerance and resistance N2 - The global rise of antibiotic resistance has made the proper use of disinfectants more important than ever. Their application in clinical l settings is an integral part of antibiotics stewardship by preventing the occurrence and spread of infections. However, improper use of disinfectants also harbours the risk for the evolution of tolerance and resistance to disinfectants, but also to antibiotics. It is therefore crucial to understand whether and how bacteria can survive chemical disinfection and which conditions facilitate the evolution of tolerance and resistance. Here, we study the heterogeneity in the response of isogenic E. coli populations exposed to different levels of commonly used disinfectants. At concentrations below the minimal inhibitory concentration (MIC), we find that certain disinfectants induce prolonged lag times in individual cells, a phenotype that has been associated with persistence against antibiotics. At concentrations above the MIC, we find heterogeneous killing for a range of the tested substances. Interestingly, for the three cationic surfactants that were tested, we find kill kinetics revealing the presence of a tolerant subpopulation that can withstand disinfection longer than most of the population. We will present results from an ongoing evolution experiment in which we test the potential for evolution of population-wide tolerance and resistance through intermittent exposure to lethal doses of a cationic surfactant. T2 - New Approaches and Concepts in Microbiology CY - Heidelberg, Germany DA - 10.07.2019 KW - Persistence KW - Biocides KW - Resistance KW - heterogeneity KW - Bacteria PY - 2019 AN - OPUS4-48524 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Trimpert, J. A1 - Groenke, N. A1 - Kunec, D. A1 - Eschke, K. A1 - He, Shulin A1 - McMahon, Dino Peter A1 - Osterrieder, N. T1 - A proofreading-impaired herpesvirus generates populations with quasispecies-like structure N2 - RNA virus populations are composed of highly diverse individuals that form a cloud of related sequences commonly referred to as a ‘quasispecies’1–3. This diversity arises as a consequence of low-fidelity genome replication4,5. By contrast, DNA Virus populations contain more uniform individuals with similar fitness6. Genome diversity is often correlated with increased Fitness in RNA viruses, while DNA viruses are thought to require more faithful genome replication. During DNA replication, erroneously incorporated bases are removed by a 3′-5′ exonuclease, a highly conserved enzymatic function of replicative DNA but not RNA polymerases. This proofreading process enhances replication fidelity and ensures the genome integrity of DNA organisms, including large DNA viruses7. Here, we show that a herpesvirus can tolerate impaired exonucleolytic proofreading, resulting in DNA virus populations, which, as in RNA viruses8, are composed of highly diverse genotypes of variable individual fitness. This indicates that herpesvirus mutant diversity may compensate for individual Fitness loss. Notably, in vivo infection with diverse virus populations results in a marked increase in virulence compared to genetically homogenous parental virus. While we cannot exclude that the increase in virulence is caused by selection of and/or interactions between individual genotypes, our findings are consistent with quasispecies dynamics. Our results contrast with traditional views of DNA virus replication and evolution, and indicate that a substantial increase in population diversity can lead to higher virulence. KW - Marek's virus KW - Virulence KW - Quasispecies KW - Evolution PY - 2019 DO - https://doi.org/10.1038/s41564-019-0547-x SN - 2058-5276 N1 - Corrigendum: Nature Microbiology 4 (2019) 2025 VL - 4 SP - 2175 EP - 2183 PB - Nature Publishing Group CY - London AN - OPUS4-48896 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Plarre, Rüdiger T1 - Uninvited and Welcomed Guests in Museums – Biological management of clothes moths and woodworms N2 - In museums and historic houses clothes, moths (Tineola bisselliella, Tinea pellionella) and the furniture beetle (Anobium punctatum) are the most economically important pests on textiles or wooden artifacts, respectively. Their management is essential to protect cultural ethnological heritage and natural history collections for future generations. Pest management strategies have changed over time. Today, intensive knowledge on pest biology and overall material science are key cornerstones in IPM concepts - also for the museum environment. The important first steps for sustainable pest management are risk assessment, early pest detection and identification of pathways of infestation. These steps are followed by physical and biological means of control, which have lately gained more importance than applying biocides. Several potentially effective biological enemies of clothes moths and woodworm have been known for a long time, but their promotion for pest control in museums and historic houses is just beginning. This short review summarizes current concepts of pest life cycle interruption by applying good quarantine and very specific biological measures. The lessons learned from recent faunistic surveys, life-history studies as well as behavioral observations of parasitoids and predators of clothes moths and woodworm may supplement the pest management tool box. The need for further research in this field is addressed. T2 - IOBC-WPRS CY - Pisa, Italy DA - 03.09.2019 KW - Biological Control KW - Museum Pests KW - Tineola bisselliella KW - Anobium punctatum KW - Apanteles carpatus KW - Baryscapus tineivorus KW - Corynetes caeruleus PY - 2019 AN - OPUS4-48901 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Borzekowski, Antje A1 - Anggriawan, R. A1 - Auliyati, M. A1 - Kunte, Hans-Jörg A1 - Koch, Matthias A1 - Rohn, S. A1 - Karlovsky, P. A1 - Maul, Ronald T1 - Formation of Zearalenone Metabolites in Tempeh Fermentation N2 - Tempeh is a common food in Indonesia, produced by fungal fermentation of soybeans using Rhizopus sp., as well as Aspergillus oryzae, for inoculation. Analogously, for economic reasons, mixtures of maize and soybeans are used for the production of so-called tempeh-like products. For maize, a contamination with the mycoestrogen zearalenone (ZEN) has been frequently reported. ZEN is a mycotoxin which is known to be metabolized by Rhizopus and Aspergillus species. Consequently, this study focused on the ZEN transformation during tempeh fermentation. Five fungal strains of the genera Rhizopus and Aspergillus, isolated from fresh Indonesian tempeh and authentic Indonesian inocula, were utilized for tempeh manufacturing from a maize/soybean mixture (30:70) at laboratory-scale. Furthermore, comparable tempeh-like products obtained from Indonesian markets were analyzed. Results from the HPLC-MS/MS analyses show that ZEN is intensely transformed into its metabolites alpha-zearalenol (alpha-ZEL), ZEN-14-sulfate, alpha-ZEL-sulfate, ZEN-14-glucoside, and ZEN-16-glucoside in tempeh production. alpha-ZEL, being significantly more toxic than ZEN, was the main metabolite in most of the Rhizopus incubations, while in Aspergillus oryzae fermentations ZEN-14-sulfate was predominantly formed. Additionally, two of the 14 authentic samples were contaminated with ZEN, alpha-ZEL and ZEN-14-sulfate, and in two further samples, ZEN and alpha-ZEL, were determined. Consequently, tempeh fermentation of ZEN-contaminated maize/soybean mixture may lead to toxification of the food item by formation of the reductive ZEN metabolite, alpha-ZEL, under model as well as authentic conditions. KW - Modified mycotoxins KW - Zearalenone sulfate KW - a-zearalenol KW - Food fermentation KW - Rhizopus and Aspergillus oryzae PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-491126 DO - https://doi.org/10.3390/molecules24152697 VL - 24 IS - 15 SP - 2697 PB - MDPI AN - OPUS4-49112 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank A1 - Nordholt, Niclas A1 - Schmidt, Selina A1 - Lewerenz, Dominique T1 - Persistence as a microbial survival strategy against biocides and its link to antibiotic resistance evolution N2 - Background: One cornerstone to prevent the spread of antibiotic resistant bacteria in clinical settings is the application of disinfectants. However, bacteria can evolve resistance to disinfectants, which in turn can confer cross-resistance to antibiotics. Additionally, clonal bacterial populations can display phenotypic heterogeneity with respect to the tolerance of antibiotic stress leading to a prolonged survival of a sub-population; this phenomenon is termed persistence. Persistence to antibiotics is an evolvable trait and can serve as a stepping stone for the evolution of genetically encoded resistance. Until now, there is a lack of systematic studies that investigate if bacterial populations establish persister subpopulations that tolerate disinfectant stress longer than most of the population. Objectives: Our objective is to investigate if persistence is a bacterial survival strategy against disinfectants. Furthermore, we investigate the mechanisms of disinfectant persistence and if persistence can evolve in the face of fluctuating exposure to disinfectants. Lastly, we test if the evolved mechanisms of disinfectant tolerance lead to disinfectant resistance and if they confer cross-tolerance and cross-resistance against antibiotics. Methods: We use time-kill assays in the presence of disinfectants and experimental evolution combined to whole-genome sequencing in the model organism E. coli. Results: We find persister sub-populations against chlorhexidine and quaternary ammonium compounds, but not to alcohols, aldehydes and oxidative compounds. We will present the relationship of mechanisms known to underlie antibiotic persister formation to the formation of persisters against disinfectants. In addition, we will present data from an ongoing evolution experiment for persistence against disinfectants. T2 - 8th Congress of European Microbiologists - FEMS 2019 CY - Glasgow, UK DA - 07.11.2019 KW - Antimicrobial resistance KW - Biocides KW - Persister cells PY - 2019 AN - OPUS4-49081 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank A1 - Nordholt, Niclas A1 - Schmidt, Selina A1 - Lewerenz, Dominique T1 - Persistence as a microbial survival strategy against biocides and its link to antibiotic resistance evolution N2 - Question: One cornerstone to prevent the spread of bacteria in clinical and industrial settings is the application of biocides including disinfectants and preservatives. However, bacteria can evolve resistance to biocides, which in turn can confer cross-resistance to antibiotics. Additionally, clonal bacterial populations can display phenotypic heterogeneity with respect to the tolerance of antibiotic stress leading to a prolonged survival of a sub-population; this phenomenon is termed persistence. Persistence to antibiotics is an evolvable trait and can serve as a stepping stone for the evolution of genetically encoded resistance. Until now, there is a lack of systematic studies that investigate if bacterial populations establish persister subpopulations that tolerate disinfectant stress longer than most of the population. Our objective is to investigate if persistence is a bacterial survival strategy against biocides. Furthermore, we investigate the mechanisms of biocide persistence and if persistence can evolve in the face of fluctuating exposure to biocides. Lastly, we test if the evolved mechanisms of biocide tolerance lead to biocide resistance and if they confer cross-tolerance and cross-resistance against antibiotics. Methods: We use time-kill assays in the presence of biocides and experimental evolution combined to whole-genome sequencing in the model organism E. coli. Results: We find persister sub-populations against chlorhexidine and quaternary ammonium compounds, but not to alcohols, aldehydes and oxidative compounds. We will present the relationship of mechanisms known to underlie antibiotic persister formation to the formation of persisters against biocides. In addition, we will present data from an ongoing evolution experiment for persistence against biocides. Conclusion There is a link between antibiotic and biocide persistence with possible implications for antibiotic resistance evolution and spread. T2 - 5th International Symposium on the Environmental Dimension of Antibiotic Resistance - EDAR 2019 CY - Hong Kong, China DA - 09.06.2019 KW - Antimicrobial resistance KW - Biocides KW - Persister cells PY - 2019 AN - OPUS4-49083 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Single-cell trait-based biodiversity in microbial communities and its link to ecosystem functioning in a stratified lake N2 - A fundamental question in ecology is how biodiversity affects ecosystem function. Biodiversity is commonly estimated based on genetic variation. We investigated a new approach that defines and measures biodiversity in complex microbial communities. We used the variation in multiple functionally-relevant, phenotypic traits measured in parallel in single cells as a metric for microbial phenotypic diversity. We studied phenotypic diversity and ecosystem functioning throughout different photosynthetic layers dominated by divergent microbial communities in the gradient of Lago di Cadagno. We determined genetic diversity by 16S and 18S amplicon sequencing and bulk ecosystem functioning (photosynthesis). In addition, we determined phenotypic diversity using single-cell technologies such as nanometer-scale secondary ion mass spectrometry (NanoSIMS) correlated with confocal laser scanning microscopy (CLSM) and scanning flow-cytometry. We measured functional trait variation between individuals in 13CO2 fixation, 15NH4+ uptake, and variation in physio-morphological cell traits, such as cell size, shape, and auto-fluorescence for various pigments related to photosynthesis. We used the distances between individuals in a multidimensional trait space to derive phenotypic trait-based diversity indices, such as trait richness, trait evenness, and trait divergence. We find that phenotypic trait divergence associates with ecosystem functioning, whereas genetic diversity does not. Including activity-based, single-cell phenotypic measurements with NanoSIMS provided an additional accuracy to the trait-based diversity assessment and allowed us to formulate hypotheses on the mechanisms that shape the correlation between phenotypic diversity and eco-system function. Together, our results show that phenotypic diversity is a meaningful concept to measure microbial biodiversity and associate it with ecosystem functioning. T2 - 8th Congress of European Microbiologists - FEMS 2019 CY - Glasgow, UK DA - 07.11.2019 KW - NanoSIMS KW - Biodiversity PY - 2019 AN - OPUS4-49077 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Single-cell trait-based biodiversity in microbial communities and its link to ecosystem functioning in a stratified lake N2 - A fundamental question in ecology is how biodiversity affects ecosystem function. Biodiversity is commonly estimated based on genetic variation. We investigated a new approach that defines and measures biodiversity in complex microbial communities. We used the variation in multiple functionally-relevant, phenotypic traits measured in parallel in single cells as a metric for microbial phenotypic diversity. We studied phenotypic diversity and ecosystem functioning throughout different photosynthetic layers dominated by divergent microbial communities in the gradient of Lago di Cadagno. We determined genetic diversity by 16S and 18S amplicon sequencing and bulk ecosystem functioning (photosynthesis). In addition, we determined phenotypic diversity using single-cell technologies such as nanometer-scale secondary ion mass spectrometry (NanoSIMS) correlated with confocal laser scanning microscopy (CLSM) and scanning flow-cytometry. We measured functional trait variation between individuals in 13CO2 fixation, 15NH4+ uptake, and variation in physio-morphological cell traits, such as cell size, shape, and auto-fluorescence for various pigments related to photosynthesis. We used the distances between individuals in a multidimensional trait space to derive phenotypic trait-based diversity indices, such as trait richness, trait evenness, and trait divergence. We find that phenotypic trait divergence associates with ecosystem functioning, whereas genetic diversity does not. Including activity-based, single-cell phenotypic measurements with NanoSIMS provided an additional accuracy to the trait-based diversity assessment and allowed us to formulate hypotheses on the mechanisms that shape the correlation between phenotypic diversity and eco-system function. Together, our results show that phenotypic diversity is a meaningful concept to measure microbial biodiversity and associate it with ecosystem functioning. T2 - 8th Congress of European Microbiologists - FEMS 2019 CY - Glasgow, UK DA - 07.11.2019 KW - NanoSIMS KW - Biodiversity PY - 2019 AN - OPUS4-49080 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pietsch, Franziska A1 - Schreiber, Frank A1 - Heidrich, Gabriele T1 - Selection of resistance in bacterial biofilms grown on antimicrobial surfaces in a multidrug environment N2 - Introduction: Biofilms are regarded as a common cause of chronic infections on medical devices. Preventive and therapeutic strategies against biofilm infections commonly involve applications of multiple antimicrobial substances: antimicrobial coatings on the implanted biomaterials in combination with systemically administered antibiotics. While this practice of combination therapy harbours the risk of developing cross-resistance, it might also provide the possibility to implement specific antimicrobial-antibiotic combinations (AACs) that can slow down the selection of antibiotic resistant strains. Hypothesis and aims: Specific AACs can exert combinatorial effects on the growth of susceptible and antibiotic-resistant Pseudomonas aeruginosa that either suppress or increase their individual effects. Our aim is to identify AACs with antagonistic or synergistic effects on pseudomonal biofilms and to understand their impact on selection of resistant strains. Specifically, we want to identify AACs that select for and against antibiotic resistance during biofilm formation. Methodology: We screened for AACs that cause antagonistic or synergistic effects on planktonic P. aeruginosa. To study the effect of antimicrobial-antibiotic exposure on resistance selection in bacterial biofilms, we will grow resistant and sensitive strains on PDMS surfaces with and without antimicrobial coatings and expose them to antibiotics. Results: Several combinations with synergistic or antagonistic interaction on the growth rate of P. aeruginosa were detected. We observed a strong antagonism when combining the antimicrobial substance chlorhexidine with the carbapenem drug meropenem. A meropenem-resistant mutant showed a selection advantage in low concentrations of chlorhexidine combined with a sub-inhibitory concentration of meropenem over the wild-type. No antagonistic effect was observed for the same combination when E. coli was exposed to chlorhexidine and meropenem, suggesting a non-chemical basis for the observed effect on P. aeruginosa. Conclusion: Gaining a better understanding about resistance selection during biofilm formation on biomedical surfaces will enable us to mitigate against biofilm-associated antimicrobial resistance. T2 - Eurobiofilms 2019 CY - Glasgow, UK DA - 03.09.2019 KW - Resistance KW - Antibiotics KW - Pseudomonas PY - 2019 AN - OPUS4-49168 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schwibbert, Karin A1 - Menzel, F. A1 - Epperlein, N. A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - Bacterial adhesion on femtosecond laser-modified polyethylene N2 - In this study, femtosecond laser-induced sub-micrometer structures are generated to modify polyethylene (PE) surface topographies. These surfaces were subjected to bacterial colonization studies with Escherichia coli and Staphylococcus aureus as test strains. The results reveal that the nanostructures do not influence S. aureus coverage, while the adhesion of E. coli is reduced. KW - Bacterial adhesion KW - Laser-modified surface KW - Polyethylene KW - Laser-induced nanostructures KW - Biofilm PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492280 DO - https://doi.org/10.3390/ma12193107 VL - 12 IS - 19 SP - 3107 PB - MDPI CY - Basel, Schweiz AN - OPUS4-49228 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kjaervik, Marit A1 - Dietrich, P. A1 - Thissen, A. A1 - Schwibbert, Karin A1 - Brown, J. A1 - Hardie, K. A1 - Unger, Wolfgang T1 - Model systems and sample preparation for surface characterisation of bacteria and biofilms by near-ambient pressure XPS N2 - Bacterial samples are typically freeze dried or cryo-prepared prior to XPS analysis to allow for measurements in ultra-high vacuum (UHV). The sample environment in the near-ambient pressure (NAP) XPS instrument EnviroESCA allows for measurements in up to 15 mbar water vapor, thus, sample preparation is no longer restricted to UHV-compatible techniques. For instance, biofilms grown in medium can be transferred directly from the medium to the measurements chamber, maintaining a humid environment throughout the measurements. Considering the complexity of bacterial samples, sample preparation must be carefully considered in order to obtain meaningful and reproducible results. In this talk, various strategies for sample preparation of bacteria and biofilms for NAP-XPS measurements will be discussed. Model systems of planktonic bacteria, artificial biofilms resembling the exopolysaccharide matrix and biofilms have been characterised in various conditions. The stability and homogeneity of the samples was assessed by monitoring the C1s core level peak at different sample locations. The quality of the XPS-spectra is also influenced by the gas environment, which will be exemplified by core level spectra of P. Fluorescens acquired in air, water vapor and ultra-high vacuum. T2 - 18th European conference on applications of surface and interface analysis (ECASIA) CY - Dresden, Germany DA - 15.09.2019 KW - NAP-XPS KW - Biofilms KW - Bacteria KW - E. coli KW - XPS PY - 2019 AN - OPUS4-49189 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koerdt, Andrea A1 - An, Biwen Annie A1 - Kleinbub, Sherin A1 - Herrmann, Annett T1 - Investigation of methanogen-induced microbiologically influenced corrosion (Mi-MIC) using simulated marine environments under flowing conditions N2 - Microbiologically influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) in offshore industries, such as the oil and gas pipelines, due to the high concentrations of sulfate in the seawater. SRM act upon the metal by the reactiveness of hydrogen sulfide (HS-), and by withdrawal of the available electrons (Fe --> Fe2+ + 2e-; E° = -0.47 V) in electrical contact with the metal (EMIC). However, methanogenic archaea can also cause MIC. Because they do not produce HS-, withdrawal of electrons may be their main corrosive mechanism; however, mechanistic details and kinetics of the overall process are poorly understood. To investigate the corrosion potential of methanogens, we studied the EMIC methanogenic strains isolated from marine sediments (Methanobacterium-affiliated strain IM1) and crude oil tanks (Methanococcus maripaludis Mic1c10), in an in-house developed flow-through cell to simulate a fluctuating environment. A co-culture of M. maripaludis and D. alaskensis was also established to study the effect of syntrophic growth on metal corrosion that may occur in industrial pipelines. Results indicate that the rates of iron corrosion due to coupled methanogenesis (up to 0.4 mm/yr) are higher to that caused by the marine SRM Desulfovibrio alaskensis (0.15 mm/yr). Surface analyses of the metal showed severe pitting with high methane production. Genomic analysis of the EMIC methanogen M. maripaludis Mic1c10 will provide an insight on the mechanisms of MIC. Such knowledge and deeper understanding also from an electrokinetic point of view may not only provide further models in microbial electrophysiology, but also contribute to mitigation strategies in MIC T2 - Archaea Meeting-Schmitten VAAM Fachgruppe CY - Schmitten, Germany DA - 12.09.2019 KW - Corrosion KW - MIC KW - Archaea KW - Methanogens KW - Environmental Simulation PY - 2019 AN - OPUS4-49405 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Haustein, T. A1 - Busweiler, Sabine A1 - Haustein, V. A1 - von Laar, C. A1 - Plarre, Rüdiger T1 - Laboratory breeding of Korynetes caeruleus (Coleoptera: Cleridae) for the biological of Anobium punctatum) (Coleoptera, Ptinidae) N2 - Larvae and adults of Korynetes caeruleus (de Geer 1775) (Coleoptera: Cleridae) were collected from old churches and reared in the laboratory on Anobium punctatum (de Geer 1774) (Coleoptera: Ptinidae). Breeding success of K. caeruleus was low, but basic parameters of this species’ developmental cycle were identifi ed. At 21°C and 75% relative humidity and a fourmonth cold period at 4°C, the development of K. caeruleus from egg to adult appearance lasted 2 years. The pupal stage may be reached and completed after one and a half years. Feeding on larvae of A. punctatum by larvae of K. caeruleus was observed and consisted of a combination of sucking haemolymph and consuming body parts. The sickle-like mandibles of larvae of K. caeruleus penetrate the cuticle of prey larvae; this is followed by pumping and sucking body movements. Adult beetles of A. punctatum were not attacked by K. caeruleus larvae. Feeding behaviour of adult K. caeruleus was not investigated. KW - Cultural heritage KW - Coleoptera KW - Korynetes caeruleus KW - Cleridae KW - Ptinidae KW - Anobium punctatum KW - Biological pest control KW - Life history data KW - Laboratory breeding KW - Wood protection PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-494999 DO - https://doi.org/10.14411/eje.2019.038 SN - 1802-8829 VL - 116 SP - 362 EP - 371 PB - České Budějovice AN - OPUS4-49499 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Selina A1 - Schreiber, Frank T1 - Antimicrobial resistance in soil microbes mediated by resistance evolution and horizontal gene transfer (HGT) N2 - Questions: Biocides are in contact with soils through direct application and passive leaching from protected materials. Consequently, soil microorganisms are exposed to toxic 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). Methods: In laboratory evolution experiments we culture selected model soil microorganism with representative biocides followed by antibiotic cross-resistance determination and genome sequencing. Moreover, we investigate if the selected biocides affect the HGT frequency of plasmids that carry resistance genes among soil microorganism and the consequences for survival of the affected populations. Results: Our initial results show only small increases of biocide resistance during serial transfers in the presence of biocides. One reason for this might be the narrow selective window for biocide resistance due to steep dose-response relationships. Furthermore, we will present results from ongoing experiments on the effects of material preservatives on HGT frequencies facilitating microbial community adaptation to stress. Conclusions: The results will enable future risk assessment regarding resistance evolution for biocides used as material preservatives. T2 - 5th International Symposium on the Environmental Dimension of Antibiotic Resistance (EDAR) CY - Hong Kong, China DA - 09.06.2019 KW - Biocides KW - Horizontal gene transfer HGT KW - Microbiology KW - Resistance evolution KW - Antimicrobial resistance PY - 2019 AN - OPUS4-49401 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Selina A1 - Schreiber, Frank T1 - Antimicrobial resistance in soil microbes mediated by resistance evolution and horizontal gene transfer (HGT) N2 - Question: Biocides are in contact with soils through direct application and passive leaching from protected materials. Consequently, soil microorganisms are exposed to toxic 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). Methods: In laboratory evolution experiments we culture selected model soil microorganism with representative biocides followed by antibiotic cross-resistance determination and genome sequencing. Moreover, we investigate if the selected biocides affect the HGT frequency of plasmids that carry resistance genes among soil microorganism and the consequences for survival of the affected populations. Results: Our initial results show only small increases of biocide resistance during serial transfers in the presence of biocides. One reason for this might be the narrow selective window for biocide resistance due to steep dose-response relationships. Furthermore, we will present results from ongoing experiments on the effects of material preservatives on HGT frequencies facilitating microbial community adaptation to stress. Conclusions: The results will enable future risk assessment regarding resistance evolution for biocides used as material preservatives. T2 - 8th Congress of European Microbiologists - FEMS 2019 CY - Glasgow, UK DA - 07.07.2019 KW - Biocides KW - Horizontal gene transfer HGT KW - Microbiology KW - Resistance evolution KW - Antimicrobial resistance PY - 2019 AN - OPUS4-49402 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koerdt, Andrea A1 - An, Biwen Annie A1 - Kleinbub, Sherin A1 - Herrmann, Annett T1 - Investigation of methanogen-induced microbiologically influenced corrosion (Mi-MIC) using simulated marine environments under flowing conditions N2 - Microbiologically influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) in offshore industries, such as the oil and gas pipelines, due to the high concentrations of sulfate in the seawater. SRM act upon the metal by the reactiveness of hydrogen sulfide (HS-), and by withdrawal of the available electrons (Fe --> Fe2+ + 2e-; E° = -0.47 V) in electrical contact with the metal (EMIC). However, methanogenic archaea can also cause MIC. Because they do not produce HS-, withdrawal of electrons may be their main corrosive mechanism; however, mechanistic details and kinetics of the overall process are poorly understood. To investigate the corrosion potential of methanogens, we studied the EMIC methanogenic strains isolated from marine sediments (Methanobacterium-affiliated strain IM1) and crude oil tanks (Methanococcus maripaludis Mic1c10), in an in-house developed flow-through cell to simulate a fluctuating environment. A co-culture of M. maripaludis and D. alaskensis was also established to study the effect of syntrophic growth on metal corrosion that may occur in industrial pipelines. Results indicate that the rates of iron corrosion due to coupled methanogenesis (up to 0.4 mm/yr) are higher to that caused by the marine SRM Desulfovibrio alaskensis (0.15 mm/yr). Surface analyses of the metal showed severe pitting with high methane production. Genomic analysis of the EMIC methanogen M. maripaludis Mic1c10 will provide an insight on the mechanisms of MIC. Such knowledge and deeper understanding also from an electrokinetic point of view may not only provide further models in microbial electrophysiology, but also contribute to mitigation strategies in MIC T2 - Einladung zum Kolloquium HZDR – Helmholtz-Zentrum Dresden-Rossendorf CY - Dresden, Germany DA - 24.09.2019 KW - Corrosion KW - MIC KW - Archaea KW - Methanogens KW - Environmental Simulation PY - 2019 AN - OPUS4-49403 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Selina A1 - Schreiber, Frank T1 - Antimicrobial resistance in soil microbes mediated by resistance evolution and horizontal gene transfer (HGT) N2 - Question: Biocides are in contact with soils through direct application and passive leaching from protected materials. Consequently, soil microorganisms are exposed to toxic 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). Methods: In laboratory evolution experiments we culture selected model soil microorganism with representative biocides followed by antibiotic cross-resistance determination and genome sequencing. Moreover, we investigate if the selected biocides affect the HGT frequency of plasmids that carry resistance genes among soil microorganism and the consequences for survival of the affected populations. Results: Our initial results show only small increases of biocide resistance during serial transfers in the presence of biocides. One reason for this might be the narrow selective window for biocide resistance due to steep dose-response relationships. Furthermore, we will present results from ongoing experiments on the effects of material preservatives on HGT frequencies facilitating microbial community adaptation to stress. Conclusions: The results will enable future risk assessment regarding resistance evolution for biocides used as material preservatives. T2 - Symposium für Doktorandinnen und Doktoranden – 2019 CY - Berlin, Germany DA - 27.09.2019 KW - Biocides KW - Horizontal gene transfer HGT KW - Microbiology KW - Resistance evolution KW - Antimicrobial resistance PY - 2019 AN - OPUS4-49404 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - An, Biwen Annie A1 - Koerdt, Andrea T1 - Investigating and modelling MIC using in-house developed flow system (Hi-Tension) N2 - Microbiologically influenced corrosion is a multidisciplinary research area. To develop successful mitigation strategies, expertise from the industry and research institutes are essential. In Department 4.1, we developed an innovative laboratory flow model (Hi-Tension) that allows effective monitoring of MIC under both standard and non-standard conditions. The flow model allows flexibility with material selection, flow rates, temperature and other environmental parameters changes. Furthermore, the flow model allows integration of electrochemical measurements using microsensors, providing a comprehensive view of corrosion at the biofilm level. Currently, initial results indicate corrosion in the flow model is significantly higher than that of standard laboratory set ups, i.e. static incubations, particularly for methane-producing microorganisms. T2 - Departmental Meeting with Helmotz Dresden CY - BAM, Berlin, Germany DA - 04.11.2019 KW - MIC KW - Corrosion KW - FIB/SEM KW - Corrosion products KW - Hi-Tension KW - Flow Model KW - Modelling PY - 2019 AN - OPUS4-49417 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - An, Biwen Annie A1 - Koerdt, Andrea A1 - Kleinbub, Sherin T1 - Microbial modelling of sulfate-reducing bacteria (SRB) and methanogenic archaea (ME) using iron N2 - Sulfate reducing bacteria (SRB) and methanogenic archaea (MA) are commonly found in the oil and gas environments. The formation of hydrogen sulfide (HS-) is particularly concerning for the petroleum industry due to its corrosiveness. However, the activities of SRB are limited to the concentration of sulfate present in the environment, whereas methanogens can utilize substrates such as H¬2 for methanogenesis. MA is commonly found in sulfate-free environments, such as deep sediments, and are known to form interspecies electron transfer relationships with SRB. Recently, SRB and MA capable of microbiologically influenced corrosion (MIC) by using elemental iron as a direct electron source (EMIC) have gained increased attention. On the iron surface, EMIC-SRB can outcompete EMIC-MA in the presence of sulfate, but this changes as sulfate depletes. The formation of FeS on the metal surface can be further utilized by MA for methanogenesis as it provides a conductive path. However, the possible kinetics involved of the overall process are currently unknown. We obtained a co-culture of EMIC-SRB and EMIC-MA to investigate the growth rates and electrical potential changes under different environmental conditions, including changes in pH, temperature and salinity. Results indicate that under neutral conditions and using iron as the sole substrate, methane production (up to 5 mM) starts after sulfate was depleted. Electrochemical measurements will be conducted on the co-culture under different conditions to determine the changes in the electrical potential in correlation with the sulfate and methane concentration. Fluorescence and electron microscope images of the biofilm structure will be used to visualize cell distribution and morphology. This study embarks the first step of understanding the relationship between EMIC-SRB and EMIC-MA. Such knowledge is important for the field of microbial electrophysiology and can be further explored for industrial applications. T2 - 7th International Symposium on Applied Microbiology and Molecular Biology in Oil Systems (ISMOS-7) CY - Halifax, Canada DA - 18.06.2019 KW - MIC KW - Corrosion KW - FIB/SEM KW - Corrosion products KW - Bacteria KW - Archaea KW - Iron PY - 2019 AN - OPUS4-49420 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -