Isolation of bacteriophages from water sources and testing host specificity as a novel antimicrobial agent

Rajapaksege, Sadali (2022) Isolation of bacteriophages from water sources and testing host specificity as a novel antimicrobial agent. (MSc(R) thesis), Kingston University, .


The emergence of antimicrobial resistance (AMR) is a growing threat to the world due to the global misuse and overuse of antibiotics. New antibiotic-resistant bacteria cannot be prevented, controlled, or killed by existing antibiotics. This has led to the search for alternative therapies, such as bacteriophages, which are ubiquitous in nature. The interest of the ‘Bacteriophage’ and its effects on bacteria has been present since 1915, where Frederick William Twort first discovered these ‘glassy organisms’. Bacteriophages are bacterial viruses that can target and lyse bacteria by replicating within the bacterium, therefore, it could be considered as an alternative therapy to combat AMR. In this study, bacteriophages were isolated from different rivers and tested against a panel of two-hundred bacteria: (one hundred and sixty-nine farm bovine) isolates and (thirty- one ESBL- producing) isolates from human samples. The organisms that were used in this study were Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, Proteus mirabilis and Klebsiella sp. Initial spot assays were used to identify phage presence in water samples. To determine the host range, spot assays were used on the isolated bacteriophages which were then tested against different isolates. This study also performed serial dilutions to determine the phage killing titre of the isolated phages and to investigate the relationship between killing titre and host range, which could be useful for phage cocktails. Due to the COVID-19 pandemic, the analysis of this study was not fully explored, however it did show that bacteriophages were readily isolated from different river water samples using bovine and human ESBL-producing isolates as phage targets. The phages in this study were found to have a variety of host ranges and killing titre. The study also highlighted that there was no correlation between host specificities and killing titre concentrations. Potential application of bacteriophages from this study to combat AMR shows to be promising, as broad range phages with high killing titre concentrations were detected. Further phage research is needed to validate phage therapy as an alternative route to decrease the risk of further antibiotic-resistant bacteria being introduced.

Actions (Repository Editors)

Item Control Page Item Control Page