Antimicrobial resistance profile of bacteria from hospital wastewater at two specialized hospitals in Bahir Dar city, Ethiopia

Abstract

BACKGROUND: The high levels of antimicrobial consumption in hospitals contribute to the occurrence of antimicrobial resistant bacteria. Antimicrobial resistant bacteria and sub-lethal concentrations of antimicrobial metabolites can end up in hospital wastewater which can spread to the environment and to the community. However, information on the resistance profile of bacteria isolated from environments is not well studied. Thus, the main aim of this study was to determine the antibiotic resistance profile of bacteria from hospital wastewater in Bahir Dar City, Northwest Ethiopia. METHOD: A total of 70 hospital wastewater samples were collected from two comprehensive specialized hospitals using a grab-sampling technique. Bacteria were identified using colony morphology, Gram staining, and biochemical tests. The drug susceptibility test was performed using the Kirby-Bauer disc diffusion method on Muller-Hinton agar. RESULT: The most dominant bacterial isolates from hospital wastewater were Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), Citrobacter spp., Acinetobacter spp., Enterobacter spp., Klebsiella pneumoniae (K. pneumoniae), and Pseudomonas aeruginosa (P. aeruginosa). All K. pneumoniae and 52.4% (11/21) E. coli were resistant to ceftazidime (third-generation cephalosporin), while Citrobacter spp., Acinetobacter spp., and Enterobacter spp., were susceptible to ceftazidime. Likewise, S. aureus revealed 64% (16/25) resistance to erythromycin. Overall, 22.2% of bacterial isolates were multidrug resistant bacteria to the commonly prescribed antimicrobials. CONCLUSION: Hospital waste waters contain high prevalence of multiple drug-resistant bacteria, particularly the third-generation cephalosporin resistant K. pneumoniae and E. coli would be a big concern. Infection prevention and control practices with proper treatment of hospital wastewater before discharging should be in practice to contain the spread of drug-resistant bacteria from hospital to external environment.