生物多样性 ›› 2025, Vol. 33 ›› Issue (3): 24101.  DOI: 10.17520/biods.2024101  cstr: 32101.14.biods.2024101

• 研究报告: 微生物多样性 •    下一篇

重金属污染土壤中细菌抗生素抗性基因分布特征

仝淼, 王欢, 张文双, 王超, 宋建潇*   

  1. 西北工业大学生态环境学院, 西安 710129
  • 收稿日期:2024-03-17 修回日期:2024-09-09 出版日期:2025-03-20 发布日期:2024-11-29
  • 通讯作者: 宋建潇

Distribution characteristics of antibiotic resistance genes in soil bacterial communities exposed to heavy metal pollution

Miao Tong, Huan Wang, Wenshuang Zhang, Chao Wang, Jianxiao Song*   

  1. School of Ecology and Environment, Northwestern Polytechnical University, Xi’an 710129, China
  • Received:2024-03-17 Revised:2024-09-09 Online:2025-03-20 Published:2024-11-29
  • Contact: Jianxiao Song

摘要: 重金属作为常见的土壤污染物, 可通过共选择作用诱导土壤微生物群落的抗生素抗性基因(antibiotic resistance genes, ARGs)的产生和扩散, 并促进ARGs在环境中持久存在。本研究建立了不同铜(Cu)浓度和镉(Cd)浓度的土壤微宇宙实验, 基于高通量测序和实时荧光定量PCR技术分析不同重金属浓度和复合污染条件下ARGs的分布特征以及土壤细菌群落对不同浓度Cu、Cd污染的响应, 旨在解析ARGs与土壤细菌群落在重金属污染土壤中的分布特征。此外, 通过探究影响ARGs变化的关键环境因子, 以期找出有效减缓环境中抗生素抗性的传播和扩散现状的途径。研究表明: 高浓度Cu (400 mg/kg)与Cd (1 mg/kg和5 mg/kg)的复合污染显著(P < 0.05)提高了土壤中抗生素抗性基因sul1、intl1、blaVIM的相对丰度, 抗生素抗性基因tetX、tetG对Cd响应最敏感, 低浓度Cd (1 mg/kg)可明显提高tetX、tetG的丰度。此外, Cu、Cd显著(P < 0.05)改变了土壤细菌群落结构, 并且使细菌群落对Cu的响应更加明显。相关性分析和网络分析表明, sul1、tetX、tetM02、blaVIM广泛分布在多个细菌门, 而ARGs的变化与细菌群落(如链霉菌属Streptomyces、慢生根瘤菌属Bradyrhizobium、BIrii41属(Polyangiales)、海无柄孢囊黏细菌属Haliangium等)的变化密切相关, 推测这些细菌可能是携带ARGs的主要宿主。

关键词: 重金属污染, 细菌群落结构, 抗生素抗性基因, 微宇宙, qPCR

Abstract

Aims: This work investigates how different soil concentrations of cadmium (Cd) and copper (Cu) affect bacterial community structure and bacterial antibiotic resistance genes (ARGs). Furthermore, we explored key environmental factors that influence ARGs expression, to identify effective approaches to mitigate the spread of antibiotic resistance within environment. 

Methods: We established a soil microcosm experiment using soil containing different concentrations of Cu and Cd. The relative expression of ARGs in the soil bacteria was determined by quantitative polymerase chain reaction (qPCR) experiments. We performed genomic sequencing/16S rRNA sequencing using the Illumina MiSeq system to assess the bacterial diversity of soil samples. 

Results: High concentrations of Cd and Cu contamination significantly increased the relative abundance of the ARGs, such as sul1, intl1, and blaVIM. The ARGs tetX and tetG were most sensitive to Cd, as their abundance significantly increased even at low concentrations of Cd. In addition, Cu and Cd clearly altered soil bacterial community structure. Overall, the change in bacterial diversity was more pronounced in response to Cu than to Cd. Correlation analysis and network analysis showed that ARGs detected in this study, such as sul1, tetX, tetM02, and blaVIM, were widely distributed across multiple bacterial phyla. Changes in ARG profiles were closely associated with variations in bacterial communities (e.g. Streptomyces, Bradyrhizobium, genus BIrii41 (Polyangiales), and Haliangium), which indicate that these genera are the potential hosts of these resistance genes. 

Conclusion: Our work provides direct evidence that heavy metals like Cu and Cd may co-select for ARGs in soil bacterial communities, which poses a potential health risk to humans.

Key words: heavy metal pollution, bacterial community structure, antibiotic resistance genes, microcosm, qPCR