Antimicrobial Resistance Gene Profiling in Wastewater from Hospital Effluents in Port Harcourt, South South Nigeria: Public Health Implications

Hospital effluents serve as reservoirs and dissemination routes for antimicrobial resistance genes, contributing to environmental resistome expansion and the emergence of community-acquired resistant infections. This study profiled antimicrobial resistance genes in wastewater samples from hospital effluents in Port Harcourt, Rivers State, South South Nigeria. Composite wastewater samples were collected monthly over six months from the effluent discharge points of three tertiary hospitals and compared to upstream municipal wastewater. DNA was extracted from filtered wastewater pellets and analysed by multiplex PCR for beta-lactamase genes including blaTEM, blaSHV, and blaCTX-M, aminoglycoside resistance genes, tetracycline resistance genes, quinolone resistance genes, and class 1 integrons. Bacteriological culture and antibiogram were performed on key indicator organisms. Hospital effluents contained significantly higher concentrations of ARGs compared to municipal wastewater. blaCTX-M was the most prevalent beta-lactamase gene, detected in 100.0% of hospital effluent samples. Class 1 integrons were found in all hospital effluent samples, indicating horizontal gene transfer potential. Quinolone resistance genes were detected downstream of effluent discharge points, suggesting environmental spread. Seasonal variation influenced ARG concentration, with higher levels during the dry season. The study demonstrates that hospital effluent in South South Nigeria is a substantial environmental source of antimicrobial resistance genes and recommends mandatory implementation of hospital effluent treatment systems, environmental AMR monitoring programmes, and integration of One Health AMR surveillance frameworks at national and state levels. Keywords: antimicrobial resistance genes, hospital effluent, wastewater, resistome, Port Harcourt