Date of Completion

2025

Document Type

Thesis

Degree Name

Bachelor of Science in Life and Health Sciences

Keywords

Bacteriophages, Wastewater treatment, Pseudomonas aeruginosa, Escherichia coli, Salmonella typhimurium, Antimicrobial resistance, Myoviridae, Siphoviridae, Biocontrol agents

Abstract

Water is essential for sustaining life, yet the Philippines faces severe water stress and contamination risks due to inadequate wastewater management. In City of Dasmariñas, untreated wastewater fosters harmful bacterial pathogens such as Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhimurium, threatening public health and environmental sustainability. Conventional wastewater treatment in the Philippines remains insufficient, with limited sewage access and rising risks of bacterial contamination leading to waterborne diseases. However, there is a lack of local research on bacteriophages as potential biocontrol agents to mitigate these pathogenic threats in wastewater. This study aimed to isolate and characterize bacteriophages from selected wastewater sites in City of Dasmariñas, Cavite, and evaluate their potential to control common waterborne bacterial pathogens such as E. coli, P. aeruginosa, and Salmonella typhimurium. From nine wastewater-derived bacteriophage samples, only Burol Main Pseudomonas aeruginosa and Sto. Cristo Pseudomonas aeruginosa, both targeting Pseudomonas aeruginosa, demonstrated lytic activity with inhibition zones ranging from 9.6– 13.6 mm. No lysis was observed against E. coli or S. typhimurium. Antibiotic susceptibility tests revealed that only Sto. Cristo Pseudomonas aeruginosa showed inhibition with gentamicin and chloramphenicol. Transmission Electron Microscopy identified Burol Main Pseudomonas aeruginosa as belonging to the Myoviridae family, while Sto. Cristo Pseudomonas aeruginosa was classified under Siphoviridae, confirming distinct morphological characteristics. This study confirmed that bacteriophages capable of lysing P. aeruginosa are present in wastewater from Burol Main and Sto. Cristo. The discovery that Burol Main Pseudomonas aeruginosa inhibited a bacteria unresponsive to multiple antibiotics underscores its potential as an alternative or complementary approach for managing antimicrobial-resistant bacteria. While other phage suspensions did not display lytic activity, they may require different conditions or hosts. Overall, this research provided foundational insight into how bacteriophages from wastewater could be harnessed to address bacterial contamination and resistance in environmental and healthcare contexts.

First Advisor

April B. Ambita

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