Isolation and characterization of bacteriophages derived from environmental waste water samples with specificity towards Klebsiella pneumoniae and Salmonella paratyphi

Abstract

Multiple drug resistance of Klebsiella pneumoniae and Salmonella variants are constantly evolving and posing a significant threat to global healthcare. Furthermore, the global rise in multidrug-resistant strains of Klebsiella pneumoniae has made therapy more challenging, the prevalence of multidrug-resistant K. pneumonia is responsible for around 80% of nosocomial infections (Cao, 2015). On the other hand, Salmonella paratyphi is the most common foodborne pathogen responsible for over 135,000 deaths annually worldwide (Hoffman & Luby, 2024). The therapeutic use of certain phage particles that target bacterial pathogens is one potential non-antibiotic treatment because it provides advantages such as efficient, non-toxic, ubiquitous, easy to prepare and can result in targeted lysis of the host. To gain extraordinary insight between phage and host interaction in the aquatic environment, samples from Buri-Ganga River, Turag River and Mirpur wastewater were collected and phage K1, K2, K3 and S were isolated and their pathogenic host systems were examined. Initially, these phages were evaluated for thermal stability, and the results showed that they were resistant at moderate temperatures but completely inactivated at higher ones. Phages K1, K2, K3, and S showed varying reactions to pH changes, but were remarkably stable in the pH range of 4.0 to 10.0. They were also assessed for their susceptibility to the organic solvents’ ethanol and chloroform, which revealed resistance to ethanol but total deactivation in the presence of chloroform. Furthermore, the study also looked at the separated phages' host range selectivity against 29 different clinically relevant bacterial strains, which showed promise for their therapeutic efficacy against a range of strains. Phages K1, K2, K3, and S demonstrated lytic efficacy against a variety of bacterial strains, including those having clinical significance, indicating their possible application in phage therapy.