Antibiotic resistance has emerged as a result of our irrational use of antibiotics, and bacteria have developed resistance mechanisms as a survival tactic against these antibiotics. Antibiotic-resistant bacteria are becoming more common in clinics, which has prompted a surge in bacteriophage therapy. The therapeutic use of bacteriophages to treat drug-resistant bacterial infections is known as phage therapy. The therapeutic potential of two bacteriophages isolated against Klebsiella pneumoniae kp01 and Salmonella sp., st01 strains was investigated in this study. The double agar overlay method was used to determine the in vitro activity of two different phages of multi-drug resistant strains. Studies on host range, stability, and life cycle analysis were conducted to characterize the phage therapeutically. To determine the effectiveness of phages against bacteria, a time-kill assay was carried out. The phages have a broad host range, stable till 50°C, and pH from 3 to 11, the adsorption time was 17 min and 7 min for kp01 and st01 phages respectively, with a short latency period. In the time-kill assay at MOI 10 and 100, there was a higher reduction in bacterial optical density. The Salmonella phage was morphologically characterized and identified as belonging to the Podoviridae family by transmission electron microscope. Both phages were found to have the ability to infect the host bacterial strains effectively. Therefore, these phages can be further studied for their efficiency in eradicating bacterial biofilms and other studies using in vivo models. 

Keywords: Antimicrobial resistance, Phage therapy, Klebsiella sp., Salmonella sp.,