Département de biochimie, de microbiologie et de bio-informatique, Faculté́ des sciences et de génie, Université́ Laval, Québec, Canada; Centre de recherche de l'institut de cardiologie et de pneumologie de Québec, Québec, Canada.
Département de biochimie, de microbiologie et de bio-informatique, Faculté́ des sciences et de génie, Université́ Laval, Québec, Canada; Centre de recherche de l'institut de cardiologie et de pneumologie de Québec, Québec, Canada; Canada Research Chair on Bioaerosols, Canada.
Sci Total Environ. 2024 Feb 20;912:169567. doi: 10.1016/j.scitotenv.2023.169567. Epub 2023 Dec 23.
The recent characterization of antibiotic resistance genes (ARGs) in clouds evidenced that the atmosphere actively partakes in the global spreading of antibiotic resistance worldwide. Indeed, the outdoor atmosphere continuously receives large quantities of particles of biological origins, emitted from both anthropogenic or natural sources at the near Earth's surface. Nonetheless, our understanding of the composition of the atmospheric resistome, especially at mid-altitude (i.e. above 1000 m a.s.l.), remains largely limited. The atmosphere is vast and highly dynamic, so that the diversity and abundance of ARGs are expected to fluctuate both spatially and temporally. In this work, the abundance and diversity of ARGs were assessed in atmospheric aerosol samples collected weekly between July 2016 and August 2017 at the mountain site of puy de Dôme (1465 m a.s.l., central France). Our results evidence the presence of 33 different subtypes of ARGs in atmospheric aerosols, out of 34 assessed, whose total concentration fluctuated seasonally from 59 to 1.1 × 10 copies m of air. These were heavily dominated by genes from the quinolone resistance family, notably the qepA gene encoding efflux pump mechanisms, which represented >95 % of total ARGs concentration. Its abundance positively correlated with that of bacteria affiliated with the genera Kineococcus, Neorhizobium, Devosia or Massilia, ubiquitous in soils. This, along with the high abundance of Sphingomonas species, points toward a large contribution of natural sources to the airborne ARGs. Nonetheless, the increased contribution of macrolide resistance (notably the erm35 gene) during winter suggests a sporadic diffusion of ARGs from human activities. Our observations depict the atmosphere as an important vector of ARGs from terrestrial sources. Therefore, monitoring ARGs in airborne microorganisms appears necessary to fully understand the dynamics of antimicrobial resistances in the environment and mitigate the threats they may represent.
最近对云的抗生素耐药基因 (ARGs) 的特征描述表明，大气积极参与了全球范围内抗生素耐药性的传播。事实上，室外大气不断接收大量的生物起源颗粒，这些颗粒来自近地表的人为或自然源。尽管如此，我们对大气耐药组的组成，特别是在中海拔（即高于 1000 米）的理解仍然非常有限。大气是广阔而高度动态的，因此 ARGs 的多样性和丰度预计会在空间和时间上波动。在这项工作中，2016 年 7 月至 2017 年 8 月期间每周在法国中部多姆山采集的大气气溶胶样本中评估了 ARGs 的丰度和多样性。我们的结果表明，在大气气溶胶中存在 33 种不同的 ARGs 亚型，其中 34 种被评估，其总浓度随季节从 59 到 1.1×10 个拷贝 m 的空气而波动。这些主要由喹诺酮耐药家族的基因主导，特别是编码外排泵机制的 qepA 基因，占总 ARGs 浓度的>95%。其丰度与与 Kinococcus、Neorhizobium、Devosia 或 Massilia 属细菌呈正相关，这些细菌在土壤中普遍存在。这一点，以及 Sphingomonas 物种的高丰度，表明自然源对空气中 ARGs 的贡献很大。尽管如此，冬季大环内酯类耐药性（特别是 erm35 基因）的增加表明，ARGs 偶尔会从人类活动中扩散。我们的观察结果描绘了大气作为陆地来源 ARGs 的重要载体。因此，监测空气中微生物中的 ARGs 对于充分了解环境中抗菌耐药性的动态并减轻它们可能带来的威胁是必要的。
