Response of sediment microbial communities to antibiotic resistance genes in an irrigation–drainage system in an integrated family farm

Abstract

Because of the extensive use of antibiotics, antibiotic resistant microorganisms are gradually becoming a threat to human health. The spatiotemporal distribution of antibiotic resistance genes in the irrigation–drainage system of integrated family farms should be further studied that is conducive to further research on the control methods of antibiotic resistance genes. Among the detected genes, tetA, tetX, sul1, sul2, qnrA, ermC, intI1, and sul1 had the highest absolute abundance (1.153 × 10⁶ lecopies/g), suggesting the universality of antibiotic resistance gene transmission. Redundancy analysis reveals Sphingomonas and Acinetobacter were the dominant antibiotic resistance gene host bacteria in irrigation–drainage systems. The structural equation revealed that bacterial communities and environmental factors significantly contributed to the antibiotic resistance gene community structure. Furthermore, the normalized stochasticity ratio revealed that planting activities affect and decisively dominate sediment bacterial communities. The structural equation model showed that environmental variables were the key driving factors for the difference in ARGs distribution in different land use types (path coefficient = 0.61, R² = 0.72, p < 0.01), which was significantly higher than intI1 and heavy metal residues. Importantly, these physical and chemical factors indirectly affect the distribution of ARGs by changing the relationship between microorganisms to regulate the succession of microbial communities. Strategies for controlling antibiotic resistance gene pollution by regulating the total nitrogen and total phosphorus of bacterial community structures in integrated family farms may be proposed by focusing on community changes in irrigation–drainage systems.