Impact of Wastewater Pollution on Antibiotic Resistance in an Algerian Waterway: A Preliminary Investigation

Wastewater contamination of freshwater ecosystems is a major driver of the spread of antibiotic resistance (AR). This preliminary study investigated the impact of wastewater pollution on the AR profiles of bacterial communities in the Oued–Zénati waterway, Algeria, across a pollution gradient. From September 2017 to May 2018, water samples were collected from an upstream reference site (P1), a site downstream of urban and hospital discharges (P2), and a downstream recovery site (P3). Physicochemical and microbiological analyses revealed a critical pollution hotspot at P2, with fecal coliform concentrations reaching 9.5 × 105 MPN/100 mL, nearly 40 times higher than at P1. From a representative subset of 33 bacterial isolates characterized in this study, susceptibility testing showed a high prevalence of resistance, with observed trends matching the pollution gradient. Specifically, 100% of isolates from the polluted sites (P2 and P3) were resistant to ampicillin, and 60% of isolates from the hotspot (P2) were resistant to amoxicillin/clavulanic acid. Conversely, all isolates remained susceptible to gentamicin. These initial findings suggest that direct wastewater discharge is creating a significant reservoir for AR, highlighting potential risks to public and environmental health and underscoring the urgent need for improved wastewater management infrastructure.