摘要
      稻田土壤是砷（As）和抗生素联合污染的潜在热点，这可能导致抗生素抗性基因（ARGs）和砷生物转化基因（ABGs）的共同选择，导致砷生物地球化学循环中抗微生物耐药性的传播和修饰。到目前为止，关于水稻土中ABG和ARG之间的这些共同选择过程和特定模式的信息很少。在此，采用16S rRNA扩增子测序、高通量定量PCR和网络分析来研究ABG和ARGs对As胁迫和施肥的动态响应。结果表明，砷胁迫增加了ARGs和可移动遗传元素（MGE）的丰度，导致抗微生物耐药性的传播风险。粪肥改良增加了稻田土壤中ABG的丰度，增强了As的动员和甲基化，对食品安全构成了风险。砷或粪肥处理增加了ABGs和ARGs共存的频率，同时携带ARGs和ABGs的宿主细菌也增加了，并且在同时施用砷和粪肥的土壤中显著增加。研究发现，多药耐药基因更倾向于与ABGs共选择，ABGs是所有处理中主要的共发生ARGs之一，而粪肥改良增加了大环内酯-林肯酰胺-链霉菌B抗性（MLSB）与ABGs.共发生的频率。厚壁菌门的芽孢杆菌和梭菌是水稻土中携带ABG和ARG的主要宿主细菌。这项研究将扩展我们对抗生素和金属基因之间的共同选择的理解，并揭示联合污染对环境的潜在影响。
Abstract
Paddy soils are potential hotspots of combined contamination with arsenic (As) and antibiotics, which may induce co-selection of antibiotic resistance genes (ARGs) and As biotransformation genes (ABGs), resulting in dissemination of antimicrobial resistance and modification in As biogeochemical cycling. So far, little information is available for these co-selection processes and specific patterns between ABGs and ARGs in paddy soils. Here, the 16S rRNA amplicon sequencing and high-throughput quantitative PCR and network analysis were employed to investigate the dynamic response of ABGs and ARGs to As stress and manure application. The results showed that As stress increased the abundance of ARGs and mobile genetic elements (MGEs), resulting in dissemination risk of antimicrobial resistance. Manure amendment increased the abundance of ABGs, enhanced As mobilization and methylation in paddy soil, posing risk to food safety. The frequency of the co-occurrence between ABGs and ARGs, the host bacteria carrying both ARGs and ABGs were increased by As or manure treatment, and remarkably boosted in soils amended with both As and manure. Multidrug resistance genes were found to have the preference to be co-selected with ABGs, which was one of the dominant co-occurring ARGs in all treatments, and manure amendment increased the frequency of Macrolide-Lincosamide-Streptogramin B resistance (MLSB) to co-occur with ABGs. Bacillus and Clostridium of Firmicutes are the dominant host bacteria carrying both ABGs and ARGs in paddy soils. This study would extend our understanding on the co-selection between genes for antibiotics and metals, also unveil the hidden environmental effects of combined pollution.

https://www.sciencedirect.com/science/article/abs/pii/S1001074222000870