The distribution of antibiotic resistance and virulence factor genes in the sediment of Inexpressible Island, East Antarctica

Inexpressible Island is a small rocky island in Terra Nova Bay, Victoria Land, Antarctica, which is an area with limited human activities. Understanding the distribution of antibiotic-resistance genes (ARGs) and virulence factor genes (VFGs) in this environment can provide key information on their potential risks to humans and their roles for microbial survival. In this study, we investigated the ARGs and VFGs in lake sediments from Inexpressible Island using metagenomic sequencing. We identified 11, 502, 071 open-reading frames (ORFs), with 1, 749 classified as ARGs and 6, 838 as VFGs. The dominant ARGs were associated with antibiotic target alteration and efflux pump mechanisms, while the VFGs were related to adherence and immune modulation functions. While associated within microbial genomes, these ARGs and VFGs were mobile genetic elements like viruses and insertion sequences, distinct from ecosystems with strong human influence. We identified 974 metagenome-assembled genomes (MAGs), with 465 being medium-to-high quality. Of these, 325 (69.9%) contained ARGs, primarily affiliated with Actinomycetota and Pseudomonadota. Additionally, 269 MAGs contained VFGs, with 174 MAGs carrying both ARGs and VFGs, highlighting significant microbial antibiotic resistance and pathogenic potential. Our findings highlight the need for ongoing monitoring of ARGs and VFGs in Antarctica, particularly in light of increasing human activity and climate change.