Kämpfer, PeterSiemens, JanThormann, KaiDüring, Rolf-AlexanderPulami, DipenDipenPulami2025-10-162025-10-162025https://jlupub.ub.uni-giessen.de/handle/jlupub/20846https://doi.org/10.22029/jlupub-20197Genus Acinetobacter is diverse, and multi-drug resistant (MDR) Acinetobacter linked infections are problematic. Studies hitherto performed in extra-clinical settings, such as biogas plants (BGPs) and wastewater treatment plants (WWTPs), lacked diversity and antimicrobial resistance (AMR) of Acinetobacter. This thesis studied the diversity and AMR of Acinetobacter in livestock manure, BGP digestates, a rural WWTP, and two urban WWTPs (receiving hospital/veterinary sewage), including upstream/downstream from the river receiving effluent located in Germany. Partial 16S rRNA/rpoB genes-based study showed highest diversity (8/14, phylotypes) in urban WWTPs influent. A. baumannii were found in manure, digestate and all stages of rural WWTP (except river upstream). BGPs and rural WWTP had novel sequence-types (18/23, STs) susceptible to antimicrobials—indicating these niches consisted diverse Acinetobacter. In urban WWTPs, Acinetobacter were also isolated from secondary sludge and anaerobic post-digestor filtrate, and mostly showed MDR phenotypes against carbapenems, colistin and ciprofloxacin, suggesting hospital waste inflow into WWTPs influenced their AMR profile and clinical relevance. Isolation of Acinetobacter from digestate, and treated sludge/anaerobic post-digestor filtrate indicated their survival in anaerobic condition, which was supported by the presence of genes encoding AMP phosphotransferase and adenylate kinase linked to processing of polyphosphates for energy. Comparative genomics of A. bohemicus strains from pig manure (QAC-21b, this study) and textile dying pond (KCTC 42081, Abbas et al. 2014) showed higher genomic contents of transposons/insertion elements, and genomic islands suggesting their adaptation to these environments containing quaternary alkyl ammonium compounds (QAACs), compared to type strain ANC 3994T (forest soil, Krizova et al. 2014). Considering Acinetobacter genome plasticity, the likelihood of selection/spread of AMR if released into environment via manure (sludge) must not be neglected. Experiments with Acinetobacters from various sources will help understand this process. Plant colonization study can provide insights into potential interactions in the rhizosphere and phyllosphere, revealing routes of Acinetobacter transmission to humans. Taking “One-Health” approach, future Acinetobacter genome comparison from different sources might help understanding evolution and adaptation from extra-clinical to clinical settings. This could help development of intervention strategies to control AMR spread in non-clinical environments.enIn Copyrightddc:630