Effects of Human Activities on Antibiotic Resistance Genes and Microbial Diversity in Lake Sediments

Human activities are the main sources of antibiotic-resistant genes (ARGs) and mobile genetic elements (MGEs) in the ecosystems of lakes. This research analyzed the abundance of four ARGs (sulI, tetX, cmlA, and aac(6′)-Ib-cr) and one MGE (intI) in sediments from the typical urban and aquacultural polluted areas in Nansi Lake, and further evaluated the risk factors affecting the distribution and occurrence of ARGs. We used 16S rRNA high-throughput sequencing to elucidate the relationship between microbial diversity and ARGs while identifying the possible hosts and sources of ARGs. The results indicated that all five ARGs and MGEs were found in the sampling areas. The abundance of ARGs varied significantly, ranging from 1.29 × 10−6 to 5.59 × 10−4 (copies per 16S rRNA), and the abundance of MGEs was 3.44 × 10−6 to 4.30 × 10−5 (copies per 16S rRNA). The values were relatively higher in the human urban and aquacultural polluted areas than in the pristine environment with minimal nutrient pollution. ARGs exhibited significant correlations with some environmental factors, indicating that environmental factors, such as NH4+-N, total organic carbon (TOC), polystyrene (PS), polyethylene (PE), and polyvinyl chloride (PVC), played crucial roles in the proliferation of ARGs. A network analysis showed that Thermoanaerobaculum, Desulfatiglans, Ignavibacterium, Vibrio, and Spirochaeta were significantly associated with ARGs and MEGs. Meanwhile, these bacterial groups were likely hosts for ARGs and MGEs in the sediments of Nansi Lake. These results underscored the various effects of human activities on the dissemination of ARGs and the composition of microbial communities.