Cotrimoxazole resistance Fluoroquinolones Gentamicin Environmental contamination Public health risk Wastewater treatment Antimicrobial susceptibility

The discharge of untreated hospital wastewater poses a public health threat due to antibiotic-resistant bacteria and residual pharmaceuticals. This study evaluated bacterial isolates from wastewater in four private hospitals in Benin City, Nigeria, for three consecutive weeks. Bacteriological analysis revealed total viable counts ranging from 1.6 × 10³ to 5.6 × 10³ CFU/mL, with the highest at Mount Gilead Hospital. Six bacterial species were identified: Staphylococcus aureus, Escherichia coli, Klebsiella sp., Proteus sp., Enterococcus sp., and Pseudomonas aeruginosa. E. coli was the most frequent (27.3%), while Enterococcus sp. was the least (9.1%). Antibiotic testing showed significant resistance, especially to β-lactam antibiotics and cotrimoxazole. Fluoroquinolones and gentamicin were more effective. The Multiple Antibiotic Resistance indices ranged from 0.3 to 0.5, with Enterococcus sp. and Pseudomonas aeruginosa showing the highest resistance. The findings highlight the potential of private hospital wastewater to spread antibiotic-resistant bacteria, emphasizing the need for improved wastewater treatment and stricter environmental regulations