| 内容提要: |
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. |