O-61 Pilot study for the characterization of antibiotic-resistant genes present in wastewater samples from a community in Grenada
Author(s):
M Matthew-Bernard, K Farmer- Diaz, V MatthewBelmer, S Cheetham, K Mitchell , C N L Macpherson, ME Ramos-Nino
Year of Presentation:
2025
Objective: Antibiotic resistance poses a significant global
threat to healthcare systems. While it is often considered a
clinical issue, non-clinical environments, such as wastewater, have recently been recognized as key contributors to the
dissemination of antibiotic-resistant genes (ARGs) into the
environment. This pilot study aimed to investigate the presence of various ARGs in municipal wastewater as a potential source of environmental contamination in a community
in Grenada.
Methods: Wastewater samples were collected between January and April 2024. Samples were homogenized, and 50 mL aliquots were centrifuged to collect pellets. DNA was extracted from the pellets using the commercially available PowerSoil® DNA Isolation Kit (Mo BIO™). The extracted DNA was analyzed using a ThermoScientific Nanodrop 2000c Spectrophotometer and screened for ARGs via PCR. Target genes included sul1, sul2, blaCTX-M, blaTEM, blaSHV, and gyrA, which confer resistance to sulfonamides, β-lactams, and fluoroquinolones.
Results: Preliminary findings revealed the presence of several ARGs in the wastewater samples. Among the 16 samples analyzed, gyrA and blaTEM were detected in 100% (16/16) of samples, blaSHV in 87.5% (14/16), blaCTX-M in 37.5% (6/16), sul1 in 81.25% (13/16), and sul2 in 18.75% (3/16).
Conclusion: These findings highlight the role of municipal wastewater as a reservoir of ARGs and emphasize the need for continued monitoring to understand the potential spillover of ARGs into aquatic environments. While this study provides baseline data, further research involving prolonged sampling periods and additional sites is necessary to capture spatial and temporal variations. Moreover, the development of improved wastewater treatment methods is critical to mitigate the release of ARGs into the environment.