TY - GEN A1 - van Leuven, Nicole A1 - Lucassen, Ralf A1 - Dicks, Anna A1 - Braß, Patrick A1 - Lipski, André A1 - Bockmühl, Dirk T1 - Does antibiotic use contribute to biofilm resistance in sink drains? A case study from four German hospital wards. N2 - As biofilms are known to harbour (multi-)resistant species, their presence in health settings must be considered critical. Although there is evidence that bacteria spread from drains to the outside, there is still a lack of research data focusing on drain biofilms from hospitals. We sampled biofilms from various wards of Helios Hospital Krefeld (Germany), where comprehensive antibiotic consumption data were available. Biofilms were analysed by cell counting, isolation of relevant bacterial groups and genetic and phenotypical resistance parameters. Data were correlated with the prescribed antibiotics of the respective ward. Furthermore, an ex-situ biofilm model was employed to investigate the influence of sub-inhibitory antibiotics on the bacterial community and the prevalence of class 1 integrons. Our results show, that every ward harboured medically relevant bacterial species. While no significant differences were found in cell counts, the median prevalence of the resistance marker gene intI1 correlated with the amount of prescribed antibiotics. In contrast, phenotypical resistances showed no similar tendency. In addition, melting curve analysis data and changes in intI1 prevalence show that the composition of the bacterial community shifted depending on the biofilm and antibiotic. Based on our results we conclude, that sub-inhibitory concentrations of antibiotics have no general effect on biofilms in terms of bacterial community shift and occurrence of antibiotic resistant species. The effect depends on the initial composition of the bacterial community, the antibiotic used and the intrinsic bacterial resistance e.g. prevalence of class 1 integrons. Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-20820 ER - TY - GEN A1 - Ralf, Lucassen A1 - Nicole, van Leuven A1 - Dirk, Bockmühl T1 - Biological and Synthetic Surfactants Increase Class I Integron Prevalence in Ex-Situ Biofilms N2 - Abstract: The role of biocides in the spread of antimicrobial resistance (AMR) has been ad-dressed but only few studies focus on the impact of surfactants on microbial diversity and AMR, although they are common constituents of cleaners, disinfectants and personal care products and are thus released into the environment in large quantities. In this study, we used an ex situ biofilm model to examine the development of four biofilms exposed to surfactants and analyzed the biofilms for their prevalence of class I integrons (intI1). We furthermore de-termined the bacterial community composition by high-resolution melt analysis and 16S ri-bosomal DNA RNA (16S rRNA) gene sequencing. Depending on the initial intrinsic prevalence of intI1 in the respective ex situ biofilm, Benzalkonium Chloride, Alkylbenzene Sulfonate and Cocamidopropyl Betaine increased intI1 prevalence by an average of up to six fold. For surfac-tants, such as Fatty Alcohol Ethoxylate and the biosurfactants Sophorolipide and Rhamnoli-pide, the mean increase in intI1 prevalence did not exceed two fold. Across all surfactants the increase of intI1 was accompanied by a shift in bacterial community composition. Especially Benzalkonium Chloride, Cocamidopropyl Betaine and Alkylbenzene Sulfonate changed the communities, while Fatty Alcohol Ethoxylate, Sophorolipide and Rhamnolipide had a lower effect on the bacterial biofilm composition. Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-18712 ER -