Aeration tanks in wastewater treatment plants are revealed as contributors to the emission and enrichment of airborne antibiotic resistance genes, raising significant public health concerns.
Antibiotic resistance is one of the most pressing global health challenges, threatening the effectiveness of treatments for infectious diseases. As antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) spread through the environment, wastewater treatment plants have emerged as a hotspot for their proliferation. Recent research conducted by a team at National Taiwan University has shed light on a previously underestimated pathway for the dissemination of ARGs: the airborne route via aeration tanks in wastewater treatment plants.
The study employed an integrated metagenomic pipeline, encompassing reference-based, assembly-based, and binning-based approaches, to investigate the role of aeration tanks in emitting ARGs into the atmosphere. The findings revealed that ARG prevalence in fine particulate matter (PM2.5) is 59.6% higher than in wastewater, underscoring the tanks' critical role in amplifying airborne ARG risks.
Two key mechanisms were identified in the study. First, preferential aerosolization of ARB, driven by ARG-carrying foam-forming bacteria, facilitates the transfer of ARGs from water to air during aeration. Second, stress co-selection mechanisms, marked by efflux pumps and stress response genes, favor airborne ARB capable of withstanding dramatic environmental changes. Together, these processes highlight aeration tanks as both sources and amplifiers of airborne ARGs.
This research is particularly significant for public health and environmental management. Airborne ARGs can travel considerable distances, potentially exposing surrounding communities to antibiotic-resistant bacteria. Wastewater treatment plant workers are also at increased risk of inhaling bioaerosols containing ARGs. The study underscores the urgent need to develop bioaerosol control strategies to minimize the spread of antibiotic resistance through the air.
By uncovering this hidden pathway for ARG dissemination, the findings underscore the critical role of wastewater treatment plants in contributing to the spread of antibiotic resistance. This research opens a new front in the global fight against this pressing health threat.
Prof. Ta-Chih Hsiao’s email address: tchsiao@ntu.edu.tw