摘要
      抗生素耐药性已成为全球卫生关注的一个主要问题，需要更好地了解抗生素耐药性细菌（ARB）的全球传播机制和洲际ARB交换。我们通过定量（q）PCR测量了抗生素抗性基因（ARGs）在大气边界层（自由对流层）上方的一个偏远高山LTER（长期生态研究）站点每两周收集一次的雨雪中的大气沉积。细菌组成通过16S rRNA基因测序进行表征，气团种源通过模拟返回轨迹和雨雪化学成分确定。我们假设自由对流层可能是ARB和ARGs全球扩散的永久储层和载体。我们的目标是i）确定ARGs是否是远程洲际的，并通过气溶胶持续扩散，ii）评估ARGs在偏远高山地区的长期大气沉积动力学，以及iii）揭示潜在的扩散ARGs污染源。我们发现ARGs-sul1（对磺酰胺类药物的耐药性）、tetO（对四环素类药物的抗性）和intI1（水平基因转移和人为污染的代表）在对流层自由气溶胶中长期且持久地分散。四环素类抗生素耐药性的主要沉积与非洲灰尘爆发的加剧相匹配。潜在的ARB大多可以追溯到农业土壤中。我们的研究表明，气团路径正在形成ARGs的洲际扩散和抗生素耐药性的全球传播，具有潜在的年际变化和远程沉积率的可预测性。由于气候调节着雾化和长程气团运动模式，我们呼吁对土地利用、气候变化和ARB长程洲际扩散之间的联系进行更仔细的评估。
Abstract
Antibiotic resistance has become a major Global Health concern and a better understanding on the global spread mechanisms of antibiotic resistant bacteria (ARB) and intercontinental ARB exchange is needed. We measured atmospheric depositions of antibiotic resistance genes (ARGs) by quantitative (q)PCR in rain/snow collected fortnightly along 4 y. at a remote high mountain LTER (Long-Term Ecological Research) site located above the atmospheric boundary layer (free troposphere). Bacterial composition was characterized by 16S rRNA gene sequencing, and air mass provenances were determined by modelled back trajectories and rain/snow chemical composition. We hypothesize that the free troposphere may act as permanent reservoir and vector for ARB and ARGs global dispersal. We aimed to i) determine whether ARGs are long-range intercontinental and persistently dispersed through aerosols, ii) assess ARGs long-term atmospheric deposition dynamics in a remote high mountain area, and iii) unveil potential diffuse ARGs pollution sources. We showed that the ARGs sul1 (resistance to sulfonamides), tetO (resistance to tetracyclines), and intI1 (a proxy for horizontal gene transfer and anthropogenic pollution) were long-range and persistently dispersed in free troposphere aerosols. Major depositions of tetracyclines resistance matched with intensification of African dust outbreaks. Potential ARB mostly traced their origin back into agricultural soils. Our study unveils that air masses pathways are shaping ARGs intercontinental dispersal and global spread of antibiotic resistances, with potential predictability for interannual variability and remote deposition rates. Because climate regulates aerosolization and long-range air masses movement patterns, we call for a more careful evaluation of the connections between land use, climate change and ARB long-range intercontinental dispersal.

https://www.sciencedirect.com/science/article/pii/S0160412022000022