Background: Waste water contains microorganisms which are continuously shed in the feces. These microorganisms especially bacteria might acquire antibiotic resistance and pose a significant threat to human health. Therefore, this work aims at isolating bacteriophage capable of infecting the isolated bacteria. Methodology: For this purpose, the grab sampling was performed at the Guheswori sewage treatment plant from the inlet in the primary treatment plant and from the outlet of the secondary treatment plant. For the isolation of bacteriophage, bacteriophage in the sewage was first enriched in an isolated pathogen, then filtered and then subjected to the isolates in the nutrient agar. Results: Pathogens like Escherichia coli, Salmonella Typhi, Enterococcus faecalis, Staphylococcus aureus, Coagulase negative Staphylococcus (CONS), Citrobacter fruendii, Enterobacter aerogenes, Proteus mirabilis, P. vulgaris, Pseudomonas aeruginosa were screened. Bacteriophage was able to infect E. coli (p < 0.001), S. Typhi (p < 0.001), E. faecalis (p = 0.182); and unable to infect S. aureus, CONS, C. fruendii, E. aerogenes, P. mirabilis, P. vulgaris, P. aeruginosa. Conclusion: Bacteriophage are able to infect and kill pathogens like E. coli, S. Typhi, E. faecalis and unable to infect S. aureus, CONS, C. fruendii, E. aerogenes, P. mirabilis, P. vulgaris, P. aeruginosa. Among all other reasons of lowering bacterial load, bacteriophages could also be one of the confounding factor. Such bacteriophage able to infect and undergo lytic cycle could be used in phage typing.
