Prevalence and risk factors of multidrug-resistant Staphylococcus aureus and Escherichia coli in hospital wastewater: a cross-sectional study

Schematic graphical abstract illustrating the workflow of the study, including hospital wastewater sample collection, bacterial isolation and culturing, laboratory processing, antimicrobial susceptibility testing, microscopic examination, catalase testing, and final identification of multidrug-resistant Staphylococcus aureus and Escherichia coli isolates from hospital wastewater samples. Antimicrobial resistance (AMR) is a serious global health threats, and hospital wastewater (HWW) is a significant source of multidrug-resistant (MDR) pathogens. Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) are important clinical aquatic pathogens. This study describes the prevalence, AMR profiles, MDR, and environmental persistence of S. aureus and E. coli in HWW samples in Multan, Pakistan. Resistance patterns were determined through phenotypic susceptibility tests, and persistence was checked through minimum inhibitory concentration (MIC) analysis (>32 μg/mL). S. aureus demonstrated higher incidence rates (53–60%) than E. coli (33–40%). The greatest levels of resistance in S. aureus were determined as 87.5% against tetracycline and cephalexin, while 83% against chloramphenicol and 67% against CN (aminoglycosides), gentamicin for E.coli. In total, 57% of the isolates were MDR, the highest rate in the effluents from the emergency ward being 71.4%. According to survival analysis, E. coli demonstrated longer persistence of 6.2 days than S. aureus 3.5 days. The main risk factors comprised poor patient compliance, lack of regulation regarding the sale of antibiotics, and biofilm formation. These findings underscore the urgent need for enhanced wastewater treatment, strengthened antimicrobial stewardship, and robust surveillance of hospital effluents in resource-limited settings.