Understanding fate and distribution of antimicrobial compounds and antimicrobial resistance genes during wastewater treatment

Antimicrobial resistance (AMR) is a global health crisis, rendering pharmaceutical action against infections ineffective, threatening lives worldwide. Antibiotics are not fully metabolised by humans or animals, leading to dispersion within sewage streams. Due to this, the final products of wastewater treatment, namely biosolids and final effluent, are considered to be reservoirs for antibiotic compounds (ACs) and antibiotic resistance genes (ARGs). This is important as the final products can be released into the surrounding natural environment, potentially affecting environmental microbial communities. In light of this, this project aimed to answer the following questions: 1. Can a method be brought together and optimised to detect antibiotic compounds and related genes within complex environmental samples? 2. Which ACs and genes are present in the different stages of wastewater treatment? 3. How do these compounds and genes persist throughout the treatment process? Are there any links that can be made? The methods resulted in tentative identification of 23 different antibiotic compounds and 119 different genes relating to antimicrobial resistance. These results showed compound and gene persistence throughout the wastewater treatment process and identified areas for further research, especially concerning absolute quantification and longitudinal studies following specific samples throughout. In conclusion, the methodology resulted in multiple ARGs and ACs across a number of major antibiotic classes being detected at the WWTP on this snapshot study. This project also provides important method development and optimisation for future studies in this area.