Metagenomic sequencing reveals the abundance and diversity of antimicrobial resistant genes (ARGs) in Butuanon River, Cebu, Philippines

This study shows that rivers can act as important reservoirs of antimicrobial resistance (AMR), with a detailed analysis of the Butuanon River revealing 153 antimicrobial resistance genes (ARGs spanning 17 antibiotic classes). Using metagenomic sequencing, the researchers found that ARG abundance and diversity increase from upstream to downstream, with notable shifts in resistance profiles along the river. While some correlations were observed between specific genes, most physicochemical factors had limited influence, although pH and temperature were linked to certain resistance types. Importantly, clinically relevant ARGs—including high-risk categories—were identified, with potential pathogenic sources traced to Enterobacteriaceae. The findings underscore the role of aquatic environments in AMR dissemination and highlight the need for environmental surveillance as part of a broader One Health strategy.