Isolation of multidrug-resistant Staphylococcus aureus from Ladies’ hostel drain water in Nuapada using novel modified MacConkey Agar: implications for environmental AMR surveillance

This study investigated the presence of multidrug-resistant (MDR) Staphylococcus aureus in drain water from a ladies’ hostel in Nuapada, Odisha, highlighting communal drainage systems as significant environmental reservoirs for antibiotic-resistant pathogens. A novel modified MacConkey agar supplemented with azithromycin and cefixime was developed, enabling selective isolation of MDR S. aureus. Biochemical tests and Gram staining confirmed the isolates’ identity, while antibiotic susceptibility testing revealed resistance to multiple antibiotic classes, underscoring their public health implications. Physicochemical analysis of the drain water indicated a nutrient-rich, hypoxic environment (BOD: 180 mg/L, COD: 420 mg/L, pH: 6.8), fostering MDR bacterial proliferation. Strong correlations between organic pollution and bacterial load emphasized the role of environmental factors in resistance dynamics. These findings highlight the need for improved sanitation and wastewater treatment in communal settings to curb the spread of MDR bacteria. The modified MacConkey agar offers a promising tool for environmental surveillance of antibiotic resistance, with potential applications in broader AMR research. This study contributes to the One Health approach, advocating for integrated strategies to mitigate antimicrobial resistance in environmental reservoirs.