Biofilm properties and multidrug resistance profile of Klebsiella pneumoniae , Escherichia coli , and Staphylococcus aureus isolated from hospital wastewater in Bangladesh

ABSTRACT Hospital wastewater flowchart showing isolation of E. coli, K. pneumoniae, and S. aureus, followed by PCR identification, antimicrobial resistance testing, and biofilm analysis revealing multidrug-resistant biofilm-forming pathogens. Hospital wastewater, a critical source of pathogenic and opportunistic bacteria carrying antimicrobial residues and resistant strains, poses serious public health and environmental risks. This study assessed the biofilm-forming ability and multidrug resistance (MDR) profiles of Klebsiella pneumoniae, Escherichia coli, and Staphylococcus aureus isolated from hospital wastewater in Savar, Bangladesh. Fifty-three samples were analyzed using selective culture, biochemical tests, PCR, disk diffusion, and crystal violet microtiter plate (CVMP) assay. Among the isolates, 28 (52.8%) were identified as E. coli, 21 (39.6%) as K. pneumoniae, and 15 (28.3%) as S. aureus. High resistance to ampicillin was observed in E. coli (75.0%), K. pneumoniae (90.5%), and S. aureus (80.0%), while the highest sensitivity was found to imipenem in K. pneumoniae (100.0%), imipenem and cefuroxime in E. coli (96.4%), and ceftaroline in S. aureus (73.3%). MDR was detected in 15 (53.6%) E. coli, 5 (23.8%) K. pneumoniae, and 9 (60.0%) S. aureus isolates. E. coli (57.1%) and S. aureus (53.3%) were notable biofilm producers, with strong biofilm formation highest in E. coli (28.6%), followed by S. aureus (33.3%) and K. pneumoniae (23.8%). These findings highlight the critical presence of MDR-biofilm-forming pathogens in hospital effluents and emphasize the urgent need for effective wastewater treatment strategies.