Events

                Antibiotic consumption has been rising globally throughout the last few decades, and consequently antibiotics have been found in many different natural environments. This pollution has given bacteria the opportunity to adapt, resulting in antibiotic resistant bacteria which are unable to be killed using conventional antibiotics. When pathogenic, these bacteria can infect humans and cause diseases that are difficult or impossible to treat. The WHO reports some 43,000 deaths annually from antibiotic resistant pathogens, with numbers rising every year.

                Resistance can occur in bacteria when their DNA mutates to produce tougher cell walls, more active efflux pumps, and other unique resistance mechanisms. These antibiotic resistant genes (ARGs) can be found in bacterial DNA and can be easily expressed or transferred to other bacteria through horizontal gene transfer (HGT) when advantageous to survival (such as in the presence of antibiotics). This transfer is facilitated by mobile genetic elements such as integrons, so their presence may indicate anthropogenic contamination.

                Wastewater treatment processes are known to contain antibiotics and have diverse microbial communities, providing ideal conditions for HGT to occur and propagate resistance in the environment. While there have been numerous studies into ARG presence in wastewater, there remains no consensus regarding gene abundance, mobility, or risk. Due to the high concentrations of plant nutrients in biosolids and wastewater effluent, they are commonly used for agricultural application, and there has been demonstrated transfer of resistance genes to the food crops being grown.

                We sampled 17 Oregon wastewater treatment plants in different regions over the course of two years (sampling summer and winter) to investigate the seasonal and geographic variations in the abundance of 13 ARGs, and the concentration of 21 antibiotics. We will also utilize metagenomic sequencing and novel machine learning algorithms to identify new ARGs, identify changes in microbial community structure, and assess risk.

This project presenter is available for live video chat on Sept. 1, 2020 from 1:00 - 2:45 p.m. PDT.