The indiscriminate use of veterinary antibiotics (VAs) poses a potential risk to soil ecosystems. However, a systematic understanding of their toxic mechanisms toward soil organisms is still lacking. We evaluated the toxic effects of three typical VAs tylosin (TYL), enrofloxacin (ENR), and chlortetracycline (CTC) on earthworms from multiple systemic levels. The three VAs inhibited earthworm growth and reproduction, induced oxidative stress, and caused dysregulation of the expression of stress-related genes. Histopathological analysis revealed severe lesions in the epidermal and intestinal structures of earthworms. These responses triggered digestive dysfunction, which may be attributed to prolonged oxidative damage and downregulation of key gene expression. In addition, VAs disrupted the gut microbiota homeostasis in earthworms, suppressed of key functional taxa, and increased the abundance of potential pathogens. Concurrently, the reshaping of the microbial network increased the risk of antibiotic resistance gene (ARG) proliferation. ARGs were enriched in earthworm guts and soil, with an enhanced potential for horizontal transfer. Together, these findings indicate that the multifaceted toxicity of VAs poses a significant threat to the soil ecosystem and public health. This study provides a scientific basis and data support for the risk assessment and management of soil ecological health under VA pollution. • VAs inhibit the growth and reproduction of earthworms. • ENR severely induces intestinal pathology and functional impairment in earthworms. • Earthworm gut microbiota homeostasis is disrupted by VAs. • TYL, ENR, and CTC specifically induce the proliferation of ARGs.
Lv et al. (Sun,) studied this question.