Metagenomic sequencing reveals multiple microbial risks in ballast tank sediments: high diversity, virulence potential, and antibiotic resistance

Ballast water and associated sediments serve as major vectors for the global transfer of microorganisms, posing significant ecological, economic, and public health risks. In this study, metagenomic sequencing was employed to comprehensively characterize the microbial communities and functional potential of sediments collected from ballast tanks of three international vessels. A total of 38,194 species were identified, with bacteria comprising over 92% of all taxa, followed by Archaea (4.3%) and Eukaryota (2.8%). Metagenomic analysis revealed 196 potential pathogenic species, primarily within Pseudomonadaceae, Enterobacteriaceae, and Vibrionaceae, underscoring the role of sediments as reservoirs for pathogens. Functional annotation demonstrated strong metabolic potential, particularly in energy and amino acid metabolism. Moreover, numerous antibiotic resistance genes (ARGs) and virulence factors (VFs) were detected, indicating risks associated with antimicrobial resistance and pathogenicity. These findings establish ballast tank sediments as a distinct and complex microbial habitat, rich in both functional diversity and potential biohazards, and the results provide critical insights and baseline data to support global ballast water and sediment management strategies aimed at mitigating microbial invasion and environmental risks. • Metagenomics reveals high microbial diversity in ballast tank sediments. • Numerous pathogens and virulence factors indicate virulence risks. • Diverse antibiotic resistance genes suggest dissemination potential.