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 - 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 - 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 DO - https://doi.org/10.5061/dryad.2jm63xszx PB - Dryad AN - OPUS4-61558 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Breitenbach, Romy A1 - Gerrits, Ruben A1 - Dementyeva, Polina A1 - Knabe, Nicole A1 - Schumacher, Julia A1 - Feldmann, Ines A1 - Radnik, Jörg A1 - Ryo, M. A1 - Gorbushina, Anna T1 - Data for "The role of extracellular polymeric substances of fungal biofilms in mineral attachment and weathering" N2 - Data for the publication "The role of extracellular polymeric substances of fungal biofilms in mineral attachment and weathering" (https://doi.org/10.1038/s41529-022-00253-1). It includes: - The Summary of the EPS concentration, EPS sugar components and EPS linkages. - The Summary of the XPS analysis of freeze-dried biofilm samples of all strains. - The Summary of the pH, Mg, SI and Fe concentration, biomass and olivine dissolution rate for each time point of all dissolution experiments. KW - Biofilms PY - 2022 DO - https://doi.org/10.26272/opus4-54901 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-54901 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -