Isolation and identification of specific bacteriophages against methicillin-resistant Staphylococcus aureus, extended-spectrum beta-lactamases-producing Escherichia coli, extended-spectrum beta-lactamases-producing Klebsiella pneumoniae, and multidrug-resistant Acinetobacter baumanniiin vitro.

Drug resistance of methicillin-resistant Staphylococcus aureus, extended-spectrum beta-lactamases-producing Escherichia coli and Klebsiella pneumoniae and multidrug-resistant Acinetobacter baumannii are also cited as one of the most important causes of community and hospital acquired infections. Phage therapy can be used as a therapeutic method for the treatment of infections caused by these bacteria. The aim of this study was to isolate bacteriophages from municipal wastewater and assess their effects against drug resistant bacterial strains. The single agar layer technique was used to investigate the bacteriolytic effect of bacteriophages. Then, the double agar layer technique was used to observe phage plaques and the transmission electron microscopy was used to study the morphology of the bacteriophages. Transparent plaque formation in a double agar layer test of methicillin-resistant S. aureus and extended-spectrum beta-lactamases-producing E. coli and K. pneumoniae indicated the lysis of bacterial cells by isolated bacteriophages. No bacteriophage against A. baumannii was isolated from municipal wastewater. The morphology of these bacteriophages was also identified by electron microscopy. The results of this study showed that bacteriophages act specifically and due to the increasing level of antibiotic resistance, phage therapy as a new treatment can open a new horizon for the treatment of multidrug resistant bacteria.