摘要

大气代表了环境传播抗生素抗性基因（ARGs）的一个不受欢迎的区域，特别是通过空气细颗粒（PM2.5），这对于普通人群的吸入暴露具有强烈的影响。我们在一个年度周期的中国特大城市工业 - 城乡横断面上检测了PM2.5中的空气中细菌和几种ARG的季节变化。季节性在农村地区最为明显，细菌总水平冬季降低显着，冬季某些ARG浓缩，春季稀释。这与城市和工业用地的季节相对一致性相反。 ARG与移动遗传元件（MGE）intI1之间的统计相关性从农村到城市和工业场所减弱，这暗示了intI1在横跨土地利用梯度的水平基因转移中的稀释作用。不同的机制可能会调节特定地点人群对可转移ARGs的暴露，并且需要确定额外的MGEs。与饮用水和农业土壤的意外摄入相比，空气中的PM2.5与人类每日摄入某些ARGs和intI1的程度相似。总的来说，这项研究强调了PM2.5在普通环境ARGs传播和人体暴露途径中的重要性。

The atmosphere represents an unappreciated compartment for the environmental dissemination of antibiotic resistance genes (ARGs), particularly via airborne fine particles (PM2.5), with strong implications for the inhalational exposure of the general population. We examined the seasonal variations in airborne bacteria and several ARGs in PM2.5 across an industrial–urban–rural transect in a megacity of China over an annual cycle. Seasonality was most apparent at the rural site with a remarkable wintertime reduction in the total level of bacteria and an enrichment of certain ARGs in winter but dilution in spring. This contrasted with the relative consistency across seasons at urban and industrial sites. The statistical correlation between ARGs and the mobile genetic element (MGE), intI1, weakened from rural to urban and industrial sites, which hints at the diluting role of intI1 in horizontal gene transfers across the land use gradient. Differing mechanisms may regulate site-specific population exposure to transferable ARGs, and the identification of additional MGEs is warranted. Compared to drinking water and the accidental ingestion of agricultural soil, airborne PM2.5 contributes to a similar extent to the human daily intake of certain ARGs and intI1. Collectively, this study highlights the importance of PM2.5 in the dissemination of, and pathways of human exposure to, common environmental ARGs.

https://pubs.acs.org/doi/abs/10.1021/acs.estlett.7b00561