Characterisation of Plasmid-Associated Antimicrobial Resistance Genes in Coastal Marine Enterobacterales from the Central Adriatic Sea: De Novo Assembly and Bioinformatic Profiling

This study examines the genomic composition and resistance potential of eight putative plasmid-derived contig assemblies reconstructed from marine Enterobacterales isolated in the central Adriatic Sea. Using a combination of Illumina-based whole genome sequencing, de novo assembly, and a multi-tool bioinformatics pipeline, we annotated antimicrobial resistance genes (ARGs), insertion sequences (ISs), and plasmid replicon types. Clinically significant resistance markers such as blaKPC, blaTEM, aacA4, tetA, and folP were identified, frequently co-localised with mobile genetic elements including IS110, IS4, and IS1182. The plasmid-associated contigs were assigned to MOBP and MOBQ types and contained replicon markers (IncP6, IncA/C2) characteristic of broad-host-range plasmids. Our findings provide valuable insight into the plasmidome of environmental Enterobacterales, emphasising the role of coastal pollution in shaping the distribution and potential mobility of antimicrobial resistance genes. This supports the One Health framework by linking environmental reservoirs to clinically relevant resistance mechanisms.