TY - CONF A1 - Mezera, Marek A1 - Mirabella, Francesca A1 - Wasmuth, Karsten A1 - Richter, Anja A1 - Schwibbert, Karin A1 - Bennet, Francesca A1 - Krüger, Jörg A1 - Hodoroaba, Vasile-Dan A1 - Bonse, Jörn T1 - Influence of the pulse repetition rate on the chemical and morphological properties of laser generated surface structures N2 - Inter-pulse accumulation of heat could affect the chemical and morphological properties of the laser processed material surface. Hence, the laser pulse repetition rate may restrict the processing parameters for specific laser-induced surface structures. In this study, the evolution of various types of laser-induced micro- and nanostructures at various laser fluence levels, effective number of pulses and at different pulse repetition rates (1 – 400 kHz) are studied for common metals/alloys (e.g. steel or titanium alloy) irradiated by near-infrared ultrashort laser pulses (925 fs, 1030 nm) in air environment. The processed surfaces were characterized by optical and scanning electron microscopy (OM, SEM), energy dispersive X-ray spectroscopy (EDX) as well as time of flight secondary ion mass spectrometry (TOF-SIMS). The results show that not only the surface morphology could change at different laser pulse repetition rates and comparable laser fluence levels and effective number of pulses, but also the surface chemistry is altered. Consequences for medical applications are outlined. T2 - European Materials Research Society Spring 2021 Meeting CY - Online meeting DA - 31.05.2021 KW - Laser-induced pariodic surface structures KW - LIPSS PY - 2021 AN - OPUS4-52778 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Richter, Anja A1 - Mezera, Marek A1 - Thiele, Dorothea A1 - Krüger, Jörg A1 - Bonse, Jörn A1 - Schwibbert, Karin T1 - Bacterial adhesion on ultrashort laser processed surfaces N2 - Bacterial biofilms are multicellular communities adhering to surfaces and embedded in a self-produced extracellular matrix. Due to physiological adaptations and the protective biofilm matrix itself, biofilm cells show enhanced resistance towards antimicrobial treatment. In medical and industrial settings, biofilms on e.g. for implants or for surfaces in food-processing industry can be a fertile source of bacterial pathogens and are repeatedly associated with persisting, nosocomial and foodborne infections. As extensive usage of antibiotics and biocides can lead to the emergence of resistances, various strategies are currently developed, tested and improved to realize anti-bacterial surface properties through surface functionalization steps avoiding antibiotics. In this study, contact-less and aseptic large-area ultrashort laser scan processing is employed to generate different surface structures in the nanometer- to micrometer-scale on technical materials, i.e. titanium-alloy, steel, and polymer. The processed surfaces were characterized by optical and scanning electron microscopy and subjected to bacterial colonization studies with Escherichia coli test strains. For each material, biofilm results of the fs-laser treated surfaces are compared to that obtained on polished (non-irradiated) surfaces as a reference. Depending on the investigated surfaces, different bacterial adhesion patterns were found, suggesting an influence of geometrical size, shape and cell appendages of the bacteria and – above all – the laser-processed nanostructure of the surface itself. T2 - European Materials Research Society Spring Meeting 2021 CY - Online Meeting DA - 31.05.2021 KW - Bacterial adhesion KW - Biofilm formation KW - Ultrashort laser processing KW - Laser-induced periodic surface structures (LIPSS) PY - 2021 UR - https://www.european-mrs.com/laser-material-processing-fundamental-interactions-innovative-applications-emrs AN - OPUS4-52765 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dinter, Adelina-Elisa A1 - An-Stepec, Biwen A1 - Wurzler, Nina A1 - Özcan Sandikcioglu, Özlem A1 - Koerdt, Andrea A1 - Meermann, Björn T1 - Deciphering corrosion processes of MIC organisms - single cell-ICP-ToF-MS analysis of archaea on solid steels N2 - ICP-ToF (time of flight) MS enables the analysis of the multi-element fingerprint of single cells. The single cell ICP-ToF-MS is used in the presented poster for the analysis of archaea involved in microbiologically influenced corrosion (MIC) of steel. By means of sc-ICP-ToF-MS, the possible uptake of individual elements from the respective steel is investigated - the information obtained will be used in the future to elucidate underlying mechanisms and develop possible material protection concepts. The work combines modern methods of analytical sciences with materials. T2 - SALSA - Make & Measure 2021 CY - Online meeting DA - 16.09.2021 KW - Sc-ICP-ToF-MS KW - Single cell analysis KW - Microbiologically influenced corrosion KW - Archaea KW - Poster presentation PY - 2021 AN - OPUS4-53337 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank A1 - Nordholt, Niclas A1 - Pietsch, Franziska A1 - Heidrich, Gabriele A1 - Ciok, Michal 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 A1 - Nordholt, Niclas A1 - Kanaris, Orestis A1 - Schmidt, Selina 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 - CONF A1 - Nordholt, Niclas A1 - Schreiber, Frank A1 - Kanaris, Orestis A1 - Schmidt, Selina 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 - World Microbe Forum (ASM, FEMS) CY - Online meeting DA - 20.06.2021 KW - Persistence KW - Biocides KW - Evolution KW - Cross-resistance KW - Biocide tolerance PY - 2021 AN - OPUS4-53167 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mezera, Marek A1 - Richter, Anja A1 - Krüger, Jörg A1 - Bonse, Jörn A1 - Schwibbert, Karin T1 - Bacterial adhesion on femtosecond laser-induced periodic surface structures N2 - Biofilm formation in industrial or medical settings is usually unwanted and leads to serious health problems and high costs. Inhibition of initial bacterial adhesion prevents biofilm formation and is, therefore, a major mechanism of antimicrobial action of surfaces. Surface topography largely influences the interaction between bacteria and surfaces which makes topography an ideal base for antifouling strategies and eco-friendly alternatives to chemical surface modifications. Femtosecond laser-processing was used to fabricate sub-micrometric surface structures on silicon and stainless steel for the development of antifouling topographies on technical materials. T2 - Future Tech Week 2020 CY - Online meeting DA - 21.09.2020 KW - Laser-induced periodic surface structures (LIPSS) KW - Bacterial adhesion KW - Biofilm growth KW - Structural color KW - Femtosecond laser processing PY - 2020 UR - http://futuretechweek.fetfx.eu/wp-content/uploads/gravity_forms/2-5432af7ecff9e0243d7383ab3f931ed3/2020/09/BioCombs4Nanofibers_Poster-for-Future_Tech_Week_2020_08-09-2020_with_Reprint-permission_for_upload.pdf AN - OPUS4-51233 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dinter, Adelina-Elisa A1 - Wurzler, Nina A1 - von der Au, Marcus A1 - Özcan Sandikcioglu, Özlem A1 - Koerdt, Andrea A1 - Meermann, Björn T1 - Examination of biological samples by means of single-cell ICP-ToF-MS N2 - Up to now, different analytical methods for single cell analysis exist focusing on key features such as size, shape, morphology and elemental composition. The combination of the latest ICP-MS techniques - ICP-ToF-MS - together with the latest developments in the field of sample delivery - micro droplet generator (MDG) – will allow a Deep insight into the composition and size of cells. Microbiologically influenced corrosion (MIC) is an oxidation of metals affected by the presence or activity (or both) of microorganisms e.g. Shewanella Putrefaciens in biofilms on the surface of the corroding material. As this can happen for example in the soil on iron pipes of water pipes, in oil tanks or on steel sheet piling, there is great interest in MIC research, not only from various industrial sectors, but also from the environmental aspect. T2 - SALSA - Make & Measure CY - Online Meeting DA - 15.10.2020 KW - SC-ICP-ToF-MS KW - Single cell analysis KW - MDG ICP-ToF-MS KW - Microdroplet generator PY - 2020 AN - OPUS4-52441 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 -