摘要

       空气传播是抗生素耐药基因（ARGs）在环境中的传播途径之一，对人类吸入性接触具有重要意义。在这项研究中，我们以中国三个地区为研究对象，揭示了大气细颗粒物（PM2.5）中细菌和ARGs的时空特征：（1）北京温带城市中细菌和ARGs的丰度季节变化大于长江三角洲和珠江三角洲亚热带城市，具有区域差异的细菌群落；（2）不受季节循环和土地利用梯度影响的ARG剖面的地理指纹；（3）目标ARG与有限细菌属之间的区域独立联系；（4） ARGs与跨区域移动遗传元素（MGEs）之间的共同相关性；以及（5）不同环境和人类介质中ARG富集高端的PM2.5。时空分化的细菌群落和ARG丰度，以及大气中ARGs的组成、迁移率和潜在宿主，对人类在时空尺度上的吸入暴露具有重要意义。通过比较中国和美国的其他ARGs摄入途径（如饮用水和食物摄入），我们确定了中国吸入ARGs的区域特定重要性以及国家特定的接触情况。因此，我们的研究强调了吸入作为环境传播的ARGs总暴露途径的一个组成部分的重要性，这反过来又可能有助于制定适应战略，以减轻在中国和其他地区的暴露风险。

       Airborne transmission is one of the environmental dissemination pathways of antibiotic resistance genes (ARGs), and has critical implications for human exposure through inhalation. In this study, we focused on three regions of China to reveal some unique spatiotemporal features of airborne bacteria and ARGs in fine aerosols (PM_2.5): (1) greater seasonal variations in the abundance of bacteria and ARGs in temperate urban Beijing than in the subtropical urban areas of the Yangtze River Delta (YRD) and Pearl River Delta (PRD) regions, with regional disparities in bacterial communities; (2) geographical fingerprints of ARG profiles independent of seasonal cycles and land-use gradients within each region; (3) region-independent associations between the targeted ARGs and limited bacterial genera; (4) common correlations between ARGs and mobile genetic elements (MGEs) across regions; and (5) PM_2.5 at the higher end of ARG enrichment across various environmental and human media. The spatiotemporally differentiated bacterial communities and ARG abundances, and the compositions, mobility, and potential hosts of ARGs in the atmosphere have strong implications for human inhalational exposure over spatiotemporal scales. By comparing other contributing pathways for the intake of ARGs (e.g., drinking water and food ingestion) in China and the U.S.A., we identified the region-specific importance of inhalation in China as well as country-specific exposure scenarios. Our study thus highlights the significance of inhalation as an integral part of the aggregate exposure pathways of environmentally disseminated ARGs, which, in turn, may help in the formulation of adaptive strategies to mitigate the exposure risks in China and beyond.

       https://www.sciencedirect.com/science/article/abs/pii/S0960852418312501?via%3Dihub