Background: Antibiotic resistant bacteria and various infections caused by them especially extensive drug resistance (XDR) strains and worrying statistics of mortality due to these strains and also the lack of a clear vision for development and production of new effective antibiotics have made the necessity of using alternative therapies more apparent. Materials and Methods: In this study, specific phages affecting the Pseudomonas aeruginosa XDR strain were extracted from hospital wastewater and their laboratory characteristics along with lysis effect on 40 XDR strains of P. aeruginosa were investigated. Results: The results indicated that three isolated phages (PaB1, PaBa2 and PaBa3) belonged to the Myoviridae and Pododoviridae families and were specific to Pseudomonas aeruginosa strains.More than 98% of phages absorbed their host in less than 10 minutes (Adsorption time <10 min) and completed their lytic cycle after 40 minutes (latent time = 40 min). Burst size of PaBa1, PaBa2 and PaBa3 was 240, 250 and 220 pfu/cell, respectively. PaBa1 lysed 62.5% of the XDR strains with the highest efficiency. The three Phage cocktail was effective against 67.5% of the studied strains. Conclusion The results of this study indicate the significant potential of these phages for therapeutic use and prophylaxis of infections caused by this bacterium.

Objectives: Gastrointestinal tract infection is still one of the serious public health problems in many geographic areas and is endemic in most countries including Iran. Early detection of the gastrointestinal tract pathogens can be extremely important. The aim of the current study was to apply a shortened time-multiplex polymerase chain reaction (PCR) for rapid and simultaneous detection of Salmonella spp., Shigella spp., and Vibrio cholera. Methods: The standard and clinical strains of Salmonella spp., Shigella spp., and V. cholerae were used in the assay. Multiplex PCR was performed and optimized based on amplification of invA, putative integrase, and ompW genes for detecting Salmonella spp., Shigella spp., and V. cholerae, respectively. The specificity of the assay was evaluated by testing 12 different bacterial species. Results: Only Salmonella spp., Shigella spp., and V. cholerae strains had positive results when subjected to the assay using multiplex PCR. The assay showed a high sensitivity, and no amplification products were observed in multiplex PCR with any of the other microorganisms. Conclusion Our study indicated that the invA, putative integrase, and ompW-based multiplex PCR assay appears to be an efficient method for rapid and simultaneous detection of Salmonella spp., Shigella spp., and V. cholerae.