Abstract:
In this study, metagenomic sequencing technology was employed to analyze water and sediment samples collected from Laizhou Bay during the dry season (May) and wet season (August) of 2022, aiming to explore the seasonal distribution characteristics of antibiotic resistance genes (ARGs) and their influencing factors. A total of 19,534 sequences belonging to 311 ARG subtypes were identified, covering 28 classes of antibiotics including Elfamycin, fluoroquinolones and aminoglycosides. In terms of the number of detected ARG subtypes, the ranking was wet season water>dry season water>dry season sediment>wet season sediment. As for the relative abundance of ARGs, the descending order was wet season sediment>dry season sediment>wet season water>dry season water. The distribution of ARGs was significantly correlated with multiple environmental factors, including pH and salinity. Moreover, the distribution of certain ARGs showed significant correlations with mobile genetic elements (MGEs) such as plasmids, integrons and insertion sequences (IS), and these correlations varied across seasons. Further analysis of metagenome-assembled genomes (MAGs) indicated that ARG hosts in water samples were mainly affiliated with
Pseudomonadota and
Bacteroidota, while those in sediment samples primarily belonged to
Pseudomonadota and
Desulfobacterota. The findings on seasonal distribution of ARGs in this study can provide scientific data to support environmental management and ecological risk assessment in this region.