Date of Publication
8-2025
Document Type
Bachelor's Thesis
Degree Name
Bachelor of Science in Biology major in Medical Biology
Subject Categories
Bacteria
College
College of Science
Department/Unit
Biology
Thesis Advisor
Florabelle D. Querubin
Llewelyn Moron-Espiritu
Defense Panel Chair
Marigold O. Uba
Defense Panel Member
Patricio Elvin L. Cantiller
Raymond Vincent F. Castillo
Abstract (English)
Urban wastewater, particularly when untreated, serves as a reservoir for microorganisms, including gram-negative bacteria known for their drug resistance and pathogenic potential. While wastewater treatment plants aim to reduce these risks, they often serve as hubs for the persistence and dissemination of such pathogens. In the Philippines, studies focused on gram-negative bacteria in untreated wastewater remain limited. This study addresses that gap by identifying and assessing the virulence of gram-negative bacteria from untreated wastewater samples collected at De La Salle University-Manila. Samples from three campus sites were cultured on Sabouraud Dextrose Agar, with isolates subjected to Gram staining and colony morphology analysis. Virulence assessment employed Tenebrio molitor larvae as a model organism, with Kaplan-Meier survival curves used to illustrate pathogenic profiles. Molecular identification was performed through a BLAST (Basic Local Alignment Search Tool) search using the NCBI nucleotide database to compare the obtained sequences against known reference sequences. Key findings revealed the presence of virulent Gram-negative bacteria, notably Pseudomonas aeruginosa, Klebsiella pneumoniae, Enterobacter cloacae, and Stutzerimonas stutzeri highlighting significant risks these bacteria may pose to public health and environmental safety. Although the study was limited to samples from the university and excluded antibiotic resistance profiling, it provides critical insights into the ecology and pathogenicity of gram-negative bacteria in urban wastewater. These results highlight the need for further research in the Philippines.
Abstract Format
html
Abstract (Filipino)
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Abstract Format
html
Language
English
Format
Electronic
Keywords
Municipal water supply--De La Salle University (Philippines); Gram-negative bacteria--Philippines; Virulence (Microbiology)
Recommended Citation
Montecillo, M. B., Punzalan, P. P., Senato, J. A., & Velina, M. R. (2025). Identification and virulence assessment of gram-negative bacteria from wastewater in De La Salle University-Manila. Retrieved from https://animorepository.dlsu.edu.ph/etdb_bio/143
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Embargo Period
8-12-2028
