Integrative Freshwater Ecology Group, Centre of Advanced Studies of Blanes-Spanish Council for Research CEAB-CSIC, Blanes E-17300, Spain.
Catalan Institute for Water Research (ICRA), Scientific and Technological Park of the University of Girona, Girona E-17003, Spain.
Environ Int. 2022 Feb;160:107077. doi: 10.1016/j.envint.2022.107077. Epub 2022 Jan 10.
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.
抗生素耐药性已成为全球主要的健康问题之一，需要更好地了解抗生素耐药菌（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）站点每隔两周收集的雨水/雪中的抗生素耐药基因（ARGs）的大气沉积。通过 16S rRNA 基因测序来描述细菌组成，通过模拟的后轨迹和雨水/雪中的化学组成来确定气团的起源。我们假设自由对流层可能是 ARB 和 ARG 全球扩散的永久储库和载体。我们的目的是：i）确定 ARGs 是否通过气溶胶进行长距离洲际持续传播，ii）评估偏远高山地区 ARGs 的长期大气沉积动态，以及 iii）揭示潜在的 ARGs 弥散污染来源。我们表明，ARGs sul1（对磺胺类药物的耐药性）、tetO（对四环素的耐药性）和 intI1（水平基因转移和人为污染的替代物）通过自由对流层气溶胶进行长距离和持续传播。四环素耐药性的主要沉积与非洲尘暴的加剧相吻合。潜在的 ARB 主要追溯到农业土壤的起源。我们的研究表明，气团途径正在塑造 ARGs 的洲际传播和抗生素耐药性的全球扩散，具有对年际可变性和远程沉积率的潜在可预测性。由于气候调节气溶胶化和长距离气团运动模式，我们呼吁更仔细地评估土地利用、气候变化和 ARB 长距离洲际传播之间的联系。
