摘要

       尽管出现了重大的公共卫生问题，但城市空气中抗生素抗性基因 (ARG) 的存在并未受到重视。在这里，我们分析了环境中对七种常见抗生素（喹诺酮类、β-内酰胺类、大环内酯类、四环素类、磺胺类、氨基糖苷类和万古霉素）有抗性的 30 个 ARG 亚型的相对丰度（作为一部分，由 16S rRNA 基因标准化）在 19 个世界城市中使用新协议的总颗粒物 (PM)。此外，还以中国西安为例，研究了它们在 PM2.5 样本中的纵向变化。在地理上，检测到 ARG 的丰度变化近 100 倍，例如，从 0.07（印度尼西亚万隆）到 5.6（美国旧金山）。发现β-内酰胺抗性基因blaTEM最为丰富，其次是喹诺酮抗性基因qepA； 2004-2014 年在西安的相对丰度分别增加了 178% 和 26%。独立于城市，基因网络分析表明空气中的 ARG 由细菌分类群贡献不同。这里的结果表明，城市空气正受到 ARG 的污染，不同的城市面临着与空气中 ARG 暴露相关的不同健康风险的挑战。这项工作强调了 ARG 的城市空气传播的威胁，以及根据公共卫生重新定义我们当前的空气质量标准的必要性。

       Despite its emerging significant public health concern, the presence of antibiotic resistance genes (ARGs) in urban air has not received significant attention. Here, we profiled relative abundances (as a fraction, normalized by 16S rRNA gene) of 30 ARG subtypes resistant to seven common classes of antibiotics, which are quinolones, β-lactams, macrolides, tetracyclines, sulfonamides, aminoglycosides, and vancomycins, in ambient total particulate matter (PM) using a novel protocol across 19 world cities. In addition, their longitudinal changes in PM2.5 samples in Xi’an, China as an example were also studied. Geographically, the ARGs were detected to vary by nearly 100-fold in their abundances, for example, from 0.07 (Bandung, Indonesia) to 5.6 (San Francisco, USA). The β-lactam resistance gene blaTEM was found to be most abundant, seconded by quinolone resistance gene qepA; and their corresponding relative abundances have increased by 178% and 26%, respectively, from 2004 to 2014 in Xi’an. Independent of cities, gene network analysis indicates that airborne ARGs were differentially contributed by bacterial taxa. Results here reveal that urban air is being polluted by ARGs, and different cities are challenged with varying health risks associated with airborne ARG exposure. This work highlights the threat of urban airborne transmission of ARGs and the need of redefining our current air quality standards in terms with public health.

https://pubs.acs.org/doi/abs/10.1021/acs.est.8b02204