Antibiotic transformation products as drivers of environmental antimicrobial resistance

While environmental antibiotic pollution is a known driver of antimicrobial resistance (AMR), the role of antibiotic transformation products (TPs) remains largely unexplored despite their frequent occurrence at concentrations matching or exceeding those of parent compounds. To address this gap, this PhD project looked at whether antibiotic TPs exert selective pressure on microbial communities in wastewater influent and compared their selection potential to parent antibiotics. Using a multi-dimensional approach combining microbiological assays and degradation kinetics, dose-dependent selection thresholds, parent-TP mixture dynamics and TP persistence across different water matrices under biotic and abiotic conditions were assessed. The study revealed that several TPs selected for intI1 genes at environmentally relevant concentrations comparable to parent antibiotics, parent-TP mixtures interacted to alter selection thresholds and specific TPs exhibited marked persistence across matrices. These findings prove that antibiotic TPs are active drivers of environmental AMR rather than inert byproducts, highlighting the critical need to incorporate TPs into environmental risk assessments and One Health mitigation strategies.

Please note this is a PhD Candidate Progress Review presentation by Pooja Lakhey.