摘要
出身背景
金属（类）可以通过共同选择效应促进抗生素抗性基因（ARGs）在环境中的传播和富集。然而，目前尚不清楚微生物暴露在不同浓度的硒（Se）中是否会影响ARGs在森林土壤中的迁移和分布。硒是一种对活生物体至关重要但潜在有害的金属（类似物）。
后果
在24个森林土壤中，沿着硒梯度（0.06–20.65 mg kg−1）检测到精确的235个ARGs，这些ARGs对7类抗生素产生耐药性。（flor）/（chlor）/（am）氯霉素抗性基因在所有样本中含量最高。ARGs的总丰度先增加后减少，有效硒含量阈值升高至0.034 mg kg−1（P = 2E−05）。一个结构方程模型表明，硒间接影响ARGs垂直迁移的主要机制是通过调节细菌群落的丰度。此外，硒的甲基化（由tehB介导）和DNA损伤的修复（由ruvB和recG介导）是森林土壤硒抗性的主要机制。共现网络分析显示，硒抗性基因、MGE和ARGs之间存在显著的相关聚类，表明存在共转移潜力。从土壤中分离出的遗忘Lelliottia amnigena YTB01能够耐受50μg mL−1氨苄青霉素和1000 mg kg−1亚硒酸钠，并且在基因组中同时携带硒抗性基因和ARGs。
结论
我们的研究表明，在中等Se压力下，ARGs的传播和富集增强，但在严重Se压力（阈值为0.034 mg kg−1有效Se含量）下，ARG的传播和浓缩受到抑制。这项试点研究中产生的数据指出了与硒污染相关的潜在健康风险及其对土壤中ARGs分布的相关影响。
Abstract
Background
Metal(loid)s can promote the spread and enrichment of antibiotic resistance genes (ARGs) in the environment through a co-selection effect. However, it remains unclear whether exposure of microorganisms to varying concentrations of selenium (Se), an essential but potentially deleterious metal(loid) to living organisms, can influence the migration and distribution of ARGs in forest soils.

Results
Precisely 235 ARGs conferring resistance to seven classes of antibiotics were detected along a Se gradient (0.06–20.65 mg kg−1) across 24 forest soils. (flor)/(chlor)/(am)phenicol resistance genes were the most abundant in all samples. The total abundance of ARGs first increased and then decreased with an elevated available Se content threshold of 0.034 mg kg−1 (P = 2E−05). A structural equation model revealed that the dominant mechanism through which Se indirectly influences the vertical migration of ARGs is by regulating the abundance of the bacterial community. In addition, the methylation of Se (mediated by tehB) and the repairing of DNA damages (mediated by ruvB and recG) were the dominant mechanisms involved in Se resistance in the forest soils. The co-occurrence network analysis revealed a significant correlated cluster between Se-resistance genes, MGEs and ARGs, suggesting the co-transfer potential. Lelliottia amnigena YTB01 isolated from the soil was able to tolerate 50 μg mL−1 ampicillin and 1000 mg kg−1 sodium selenite, and harbored both Se resistant genes and ARGs in the genome.

Conclusions
Our study demonstrated that the spread and enrichment of ARGs are enhanced under moderate Se pressure but inhibited under severe Se pressure in the forest soil (threshold at 0.034 mg kg−1 available Se content). The data generated in this pilot study points to the potential health risk associated with Se contamination and its associated influence on ARGs distribution in soil.

https://link.springer.com/article/10.1186/s40793-022-00419-z