Bacteriophages from faecal contamination are an important reservoir for AMR in aquatic environments

Area of Science:

• Environmental microbiology
• Antimicrobial resistance
• Molecular biology

Background:

• Bacteriophages are key vectors for antibiotic resistance genes (ARGs).
• Faecal contamination introduces phages and ARGs into aquatic ecosystems.
• Increased phage loading from faecal matter can elevate environmental antimicrobial resistance (AMR).

Purpose of the Study:

• To investigate the link between faecal pollution and ARGs carried by phages in three Irish rivers.
• To assess the prevalence of specific ARGs (blaTEM, tet(O), qnrS, sul1) in phage particles.
• To evaluate the impact of agricultural and urban activities on ARG levels in aquatic environments.

Main Methods:

• Phage isolation and DNA extraction from river water samples.
• Detection of four specific ARGs (blaTEM, tet(O), qnrS, sul1) using molecular techniques.
• Comparison of ARG levels in phage particles from different sampling sites (source, agricultural, urban).

Main Results:

• All four targeted ARGs were detected in phage fractions across all three rivers (Liffey, Tolka, Dodder).
• ARGs were more prevalent in phage particles from agricultural and urban sites compared to river sources.
• Phages were confirmed as significant reservoirs of ARGs in the aquatic environment.

Conclusions:

• Faecal pollution significantly contributes to the prevalence of ARGs in aquatic environments.
• Agricultural and urban activities exacerbate the spread of ARGs via phages.
• Phages should be considered crucial indicators for assessing environmental AMR and water quality.