Abstract View
Exposure to Bacterial Aerosols with Antimicrobial Resistance at Septic Systems
GABRIELA RAMOS, Maria King, Texas A&M University
Abstract Number: 196
Working Group: Bioaerosols
Abstract
The aim of this study is to understand the role of aerosolization on the potential spread of antimicrobial-resistant bacteria and genes (ARB/ARGs) from wastewater effluents. During the spraying process aerosolized ARB/ARGs can spread far from septic tank systems into houses, degrading indoor air quality and posing risks to residents. Bioaerosols from common wastewater treatment plants can be found 10 km downwind of the plant boundaries. However, a septic tank system is required to be only 5 ft away from the house. It is critical to evaluate the aerosolization of ARB/ARGs from septic tank effluents to evaluate their potential contamination of the indoor air quality in nearby residences. The system in this study consists of four tanks connected by a filtration system. Aerosol samples at each tank were collected in the winter and summer with open and closed lids to observe the effect they may have on the emission of bioaerosols. The water inside each septic tank was also sampled to compare the bacteria concentration to the bioaerosol samples. The results of culturing, Kirby-Bauer antimicrobial testing, quantitative real-time polymerase chain reaction, and microbiome analysis showed lower concentrations of bacteria in the aerosols compared to the water samples. Aerosolized bacteria showed resistance to less than 50% of the antibiotics tested, lower in comparison to the 87.5% resistance in the water samples. Seasonality has also affected the antimicrobial resistance of the aerosolized bacteria. In the winter season, higher levels of resistance were detected mostly against beta-lactam antibiotics, while the summer season displayed lower levels of resistance. Operational conditions, discharge methods, humidity, temperature, airflow, and quorum sensing may all have an effect on the composition of the microbiome. After further analysis of septic tank effluents to surrounding outdoor and indoor air, mitigation methods of ARB/ARGs exposure will be applied and tested.