Phenotypic characterization and plasmid DNA profiling of multidrug resistant Escherichia coli and Staphylococcus aureus in wastewater effluents from healthcare environments in Lafia, Nigeria

Background: Multiple drug resistant Escherichia coli and Staphylococcus aureus are common causes of severe nosocomial infections and has been implicated as major contaminants within the hospital environment. This study was aimed at determining the multidrug resistance and plasmid carriage status among Escherichia coli and Staphylococcus aureus isolates in wastewater effluents from healthcare facilities in Lafia, Nigeria.Methods: A total of ۲۳۱ effluent samples were collected from different units within the healthcare environments and bacterial identification performed using standard CLSI identification techniques. Multidrug resistance was analyzed using Kirby-Bauer disc diffusion method while plasmid DNA was extracted by alkaline lysis and separated using ۰.۸% agarose gel electrophoresis. Results: Escherichia coli and Staphylococcus aureus had highest resistance to amoxicillin with values of ۷۹.۰% and ۶۶.۳% while least resistance were obtained with levofloxacin (۲۶.۳%) and cotrimoxazole (۲۵.۱%) respectively. There was no significant association between the phenotypic antibiograms of isolates and various wastewater outlets (p>۰.۰۵). A total of ۷۷(۴۶.۱%) E. coli and ۵۱ (۲۹.۱%) S. aureus isolates were resistant to all antibiotics. Most isolates had MARI values >۰.۵ with ۸۷.۴% of E. coli and ۸۰.۶% of S. aureus exhibiting multidrug resistance. Plasmid profile analysis for E. coli revealed highest number of selected isolates (۴۶.۷%) had double plasmids (size range: ۱۵۰۰ – ۶۰۰۰bp) and ۶.۷% had no plasmid while ۵۳.۳% and ۴۶.۷% of S. aureus isolates had single (۷۵۰۰bp) and no plasmid respectively. Conclusion: Effluents from the healthcare environments in the study community were heavily burdened with multidrug resistant test organisms that harbored resistant plasmids.

کلیدواژه ها:

Multidrug Resistance ، plasmid profiling ، hospital effluents ، Escherichia coli ، Staphylococcus aureus ، Nigeria