Biological Interactions Mediate Soil Functions by Altering Rare Microbial Communities.

Soil microbes, the main driving force of terrestrial biogeochemical cycles, facilitate soil organic matter turnover. However, the influence of the soil fauna on microbial communities remains poorly understood. We investigated soil microbiota dynamics by introducing competition and predation among fauna into two soil ecosystems with different fertilization histories. The interactions significantly affected rare microbial communities including bacteria and fungi. Predation enhanced the abundance of C/N cycle-related genes. Rare microbial communities are important drivers of soil functional gene enrichment. Key rare microbial taxa, including SM1A02, Gammaproteobacteria, and HSB_OF53-F07, were identified. Metabolomics analysis suggested that increased functional gene abundance may be due to specific microbial metabolic activity mediated by soil fauna interactions. Predation had a stronger effect on rare microbes, functional genes, and microbial metabolism compared to competition. Long-term organic fertilizer application increased the soil resistance to animal interactions. These findings provide a comprehensive understanding of microbial community dynamics under soil biological interactions, emphasizing the roles of competition and predation among soil fauna in terrestrial ecosystems.

Effects of heavy metal and disinfectant on antibiotic resistance genes and virulence factor genes in the plastisphere from diverse soil ecosystems.

Antibiotic-resistance genes (ARGs) are world-wide contaminants posing potential health risks. Quaternary ammonium compounds (QACs) and heavy metals can apply selective pressure on antibiotic resistance. However, there is a lack of evidence regarding their coupled effect on changes in ARGs and virulence factor genes (VFGs) in various soil types and their plastispheres. Herein, we conducted a microcosm experiment to explore the abundances and profiles of ARGs and VFGs in soil plastispheres from three distinct types of soils amended with Cu and disinfectants. The plastispheres enriched the ARGs' abundance compared to soils and stimulated the coupling effect of combined pollutants on promoting the abundances of ARGs and VFGs. Horizontal gene transfer inevitably accelerates the propagation of ARGs and VFGs in plastispheres under pollutant stress. In plastispheres, combined exposure to disinfectants and Cu increased some potential pathogens' relative abundances. Moreover, the combined effect of disinfectants and Cu on ARGs and VFGs changed with soil type in plastispheres, emphasising the necessity to incorporate soil type considerations into health risk assessments for ARGs and VFGs. Overall, this study highlights the high health risks of ARGs under the selective pressure of combined pollutants in plastispheres and provides valuable insights for future risk assessments related to antibiotic resistance.

A new insight into the potential drivers of antibiotic resistance gene enrichment in the collembolan gut association with antibiotic and non-antibiotic agents.

Effects of non-antibiotic pharmaceuticals on antibiotic resistance genes (ARGs) in soil ecosystem are still unclear. In this study, we explored the microbial community and ARGs variations in the gut of the model soil collembolan Folsomia candida following soil antiepileptic drug carbamazepine (CBZ) contamination, while comparing with antibiotic erythromycin (ETM) exposure. Results showed that, CBZ and ETM all significantly influenced ARGs diversity and composition in the soil and collembolan gut, increasing the relative abundance of ARGs. However, unlike ETM, which influences ARGs via bacterial communities, exposure to CBZ may have primarily facilitated enrichment of ARGs in gut through mobile genetic elements (MGEs). Although soil CBZ contamination did not pose an effect on the gut fungal community of collembolans, it increased the relative abundance of animal fungal pathogens contained therein. Soil ETM and CBZ exposure both significantly increased the relative abundance of Gammaproteobacteria in the collembolan gut, which may be used to indicate soil contamination. Together, our results provide a fresh perspective for the potential drivers of non-antibiotic drugs on ARG changes based on the actual soil environment, revealing the potential ecological risk of CBZ on soil ecosystems involving ARGs dissemination and pathogens enrichment.

[Research advances in ecological risk of antibiotic resistance genes]. / æŠ—ç”Ÿç´ æŠ—æ€§åŸºå› çš„ç”Ÿæ€é£Žé™©ç ”ç©¶è¿›å±•.

Antibiotics have played an important role in the prevention and treatment of human and animal diseases as well as the improvement of animal products. However, the mass products and application of antibiotics, especially the abuse in animal industry and clinical medicine, led to the widespread of antibiotic resistance genes (ARGs) in the environment. They spread widely through conjugation, transposition, and transformation with the help of movable elements such as plasmid, transposon and integrons, resulting in the continuous enhancement of microbial medicinal properties and posing a serious threat to human health and ecological security. At present, great attention has been paid to the impacts of ARGs on human health, but limited research on the ecological risk of ARGs in the environment. Here, the status quo and ecological risks of ARGs pollution were summarized, and the future research priorities in this field were prospected. We hope it could pave the way for further studies and give references for the ecological control and prevention of ARGs pollution.