摘要
      细菌中的抗生素耐药性正在成为世界范围内一个主要的卫生问题。大量使用抗生素来维持人类活动，导致细菌中抗生素抗性基因（ARGs）的快速获取和维持，并传播到环境中。最终，这些物质可以通过大气传输远距离传播。在这里，我们评估了云层中ARGs的存在，作为大气中抗生素耐药性长途旅行潜力的指标。我们假设各种ARG可以达到主要位于自由对流层内的云层高度。一旦进入大气层，它们就会被有效地输送，并且它们各自的浓度应该根据气团的来源和地理来源而有所不同。2019年9月至2021年10月，我们在多姆峰（法国海拔1465米）的气象站部署了高流速撞击器，收集了12团云。通过流式细胞术评估空气中细菌的总浓度，并通过qPCR定量抗生素耐药性的主要家族（喹诺酮类、磺酰胺类、四环素类、糖肽类、氨基糖苷类、β-内酰胺酶类、大环内酯类）的ARGs亚型，包括一种可移动的遗传元件（转座酶）。我们的结果表明，在1.01×103至1.61×104拷贝m−3的空气中，存在29种不同的ARGs亚型。在海洋地区（大西洋）上空输送的气团中的云和受大陆表面影响的云之间可以观察到明显的区别。具体而言，喹诺酮类（主要是qepA）耐药性基因在海云中普遍存在（平均占总ARGs的54%），而磺酰胺、四环素的贡献更高；在大陆云中发现了糖肽、β-内酰胺酶和大环内酯。这项研究首次证明了云中微生物ARGs的浓度与其他自然环境相当。这突出表明大气层是大规模传播ARG的途径。
Abstract
Antibiotic resistance in bacteria is becoming a major sanitary concern worldwide. The extensive use of large quantities of antibiotics to sustain human activity has led to the rapid acquisition and maintenance of antibiotic resistant genes (ARGs) in bacteria and to their spread into the environment. Eventually, these can be disseminated over long distances by atmospheric transport. Here, we assessed the presence of ARGs in clouds as an indicator of long-distance travel potential of antibiotic resistance in the atmosphere. We hypothesized that a variety of ARGs can reach the altitude of clouds mainly located within the free troposphere. Once incorporated in the atmosphere, they are efficiently transported and their respective concentrations should differ depending on the sources and the geographical origin of the air masses. We deployed high-flow rate impingers and collected twelve clouds between September 2019 and October 2021 at the meteorological station of the puy de Dôme summit (1465 m a.s.l., France). Total airborne bacteria concentration was assessed by flow cytometry, and ARGs subtypes of the main families of antibiotic resistance (quinolone, sulfonamide, tetracycline; glycopeptide, aminoglycoside, β-lactamase, macrolide) including one mobile genetic element (transposase) were quantified by qPCR. Our results indicate the presence of 29 different ARGs' subtypes at concentrations ranging from 1.01 × 103 to 1.61 × 104 copies m−3 of air. Clear distinctions could be observed between clouds in air masses transported over marine areas (Atlantic Ocean) and clouds influenced by continental surfaces. Specifically, quinolones (mostly qepA) resistance genes were prevalent in marine clouds (54 % of the total ARGs on average), whereas higher contributions of sulfonamide, tetracycline; glycopeptide, β-lactamase and macrolide were found in continental clouds. This study constitutes the first evidence for the presence of microbial ARGs in clouds at concentrations comparable to other natural environments. This highlights the atmosphere as routes for the dissemination of ARGs at large scale.

https://www.sciencedirect.com/science/article/abs/pii/S0048969722083681