A multi-color flow cytometry method coupled with fluorescent staining was developed to detect and quantify E. faecalis concentrations in coastal waters as an alternative to the traditional membrane filtration method. The developed method was used to characterize E. faecalis during batch growth and yielded consistent results across the various physiological states of the cells. Additionally, the application of propidium iodide (i.e., a viability stain), afforded the method the ability to differentiate between cells with intact and compromised cell membranes, which raises the potential of quantifying cells that are in viable-but-non-culturable (VBNC) state. Initial field test using natural seawater samples spiked with E. faecalis, demonstrated high accuracy (98-120 % recovery rate) and precision (6-10% CV) of the method to detect E. faecalis. The short analysis time (~ 2 hours) and absence of labor-intensive steps (vacuum filtration, agar plating, and a series of confirmatory steps), increase the potential for the method to increase the throughput of routine monitoring of water quality. A shorter response time to potential outbreaks of E. faecalis and the ability to quantify VBNC cells would further reduce risks to public health and safety.
","abstract_html":"<p>A multi-color flow cytometry method coupled with fluorescent staining was developed to detect and quantify <em>E. faecalis</em> concentrations in coastal waters as an alternative to the traditional membrane filtration method. The developed method was used to characterize <em>E. faecalis </em>during batch growth and yielded consistent results across the various physiological states of the cells. Additionally, the application of propidium iodide (i.e., a viability stain), afforded the method the ability to differentiate between cells with intact and compromised cell membranes, which raises the potential of quantifying cells that are in viable-but-non-culturable (VBNC) state. Initial field test using natural seawater samples spiked with <em>E. faecalis</em>, demonstrated high accuracy (98-120 % recovery rate) and precision (6-10% CV) of the method to detect <em>E. faecalis</em>. The short analysis time (~ 2 hours) and absence of labor-intensive steps (vacuum filtration, agar plating, and a series of confirmatory steps), increase the potential for the method to increase the throughput of routine monitoring of water quality. A shorter response time to potential outbreaks of <em>E. faecalis</em> and the ability to quantify VBNC cells would further reduce risks to public health and safety.</p>","abstract_has_math":false,"creators":["Magbitang, Riza"],"institution":null,"degree_name":"Master of Science (MS)","degree_level":"Masters Thesis","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Kristina Mojica","Alan Shiller","Stephan Howden"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2024,"date_issued":"2024-08-01T07:00:00Z","date_published":"2024-08-01T07:00:00Z","updated_at":"2026-07-24T05:45:40Z","subjects":["E. faecalis","Multi-color Flow Cytometry","Fluorescently labeled Antibodies","Analytical Chemistry","Environmental Monitoring","Marine Biology","Water Resource Management"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://aquila.usm.edu/masters_theses/1048","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Kristina Mojica","Alan Shiller","Stephan Howden"]},{"key":"dc:creator","label":"Author","values":["Magbitang, Riza"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2025-07-31T07:00:00Z"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Masters Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science (MS)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["E. faecalis","Multi-color Flow Cytometry","Fluorescently labeled Antibodies","Analytical Chemistry","Environmental Monitoring","Marine Biology","Water Resource Management"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://aquila.usm.edu/masters_theses/1048"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["A multi-color flow cytometry method coupled with fluorescent staining was developed to detect and quantify E. faecalis concentrations in coastal waters as an alternative to the traditional membrane filtration method. The developed method was used to characterize E. faecalis during batch growth and yielded consistent results across the various physiological states of the cells. Additionally, the application of propidium iodide (i.e., a viability stain), afforded the method the ability to differentiate between cells with intact and compromised cell membranes, which raises the potential of quantifying cells that are in viable-but-non-culturable (VBNC) state. Initial field test using natural seawater samples spiked with E. faecalis, demonstrated high accuracy (98-120 % recovery rate) and precision (6-10% CV) of the method to detect E. faecalis. The short analysis time (~ 2 hours) and absence of labor-intensive steps (vacuum filtration, agar plating, and a series of confirmatory steps), increase the potential for the method to increase the throughput of routine monitoring of water quality. A shorter response time to potential outbreaks of E. faecalis and the ability to quantify VBNC cells would further reduce risks to public health and safety.
"]},{"key":"dc:title","label":"Title","values":["Development of a Flow Cytometry Method for the Identification and Enumeration of Enterococcus faecalis"]}]}],"canonical_facts":{"dc:contributor":["Kristina Mojica","Alan Shiller","Stephan Howden"],"dc:creator":["Magbitang, Riza"],"dc:date.available":["2025-07-31T07:00:00Z"],"dc:description.abstract":["A multi-color flow cytometry method coupled with fluorescent staining was developed to detect and quantify E. faecalis concentrations in coastal waters as an alternative to the traditional membrane filtration method. The developed method was used to characterize E. faecalis during batch growth and yielded consistent results across the various physiological states of the cells. Additionally, the application of propidium iodide (i.e., a viability stain), afforded the method the ability to differentiate between cells with intact and compromised cell membranes, which raises the potential of quantifying cells that are in viable-but-non-culturable (VBNC) state. Initial field test using natural seawater samples spiked with E. faecalis, demonstrated high accuracy (98-120 % recovery rate) and precision (6-10% CV) of the method to detect E. faecalis. The short analysis time (~ 2 hours) and absence of labor-intensive steps (vacuum filtration, agar plating, and a series of confirmatory steps), increase the potential for the method to increase the throughput of routine monitoring of water quality. A shorter response time to potential outbreaks of E. faecalis and the ability to quantify VBNC cells would further reduce risks to public health and safety.
"],"dc:identifier":["https://aquila.usm.edu/masters_theses/1048"],"dc:subject":["E. faecalis","Multi-color Flow Cytometry","Fluorescently labeled Antibodies","Analytical Chemistry","Environmental Monitoring","Marine Biology","Water Resource Management"],"dc:title":["Development of a Flow Cytometry Method for the Identification and Enumeration of Enterococcus faecalis"],"thesis:degree_level":["Masters Thesis"],"thesis:degree_name":["Master of Science (MS)"]},"updated_at":"2026-07-24T05:45:40Z"}