Honors Theses
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Date of Award
2024
Document Type
Honors Thesis - NSU Access Only
Degree Type
Bachelors of Science
Degree Name
Biology
Department
Halmos College of Arts and Sciences and the Guy Harvey Oceanographic Research Center
Honors College
Farquhar Honors College Thesis
Honors College Dean
Andrea Nevins, Ph.D., M.F.A.
Home College Dean
Holly Lynn Baumgartner, Ph.D.
Faculty Advisor
Mark Cayabyab, Ph.D.
Abstract
COVID-19 continues to pose a serious threat to public health despite the availability of effective vaccinations because of the rise of SARS CoV-2 variations, vaccine reluctance, and disparities in health. While much of the COVID-19 vaccine and therapeutic research efforts are focused on preventing or treating systemic infection, local infection of the lungs, the nose and oral cavity has been overlooked as a critical site of infection and source of viral dissemination. The loss of taste is one of the earliest symptoms of SARS CoV-2, while the viral load in saliva is as high as in the lower airway mucus. The long-term goal of this project/honors thesis was to elucidate the role of the oral cavity, especially the oral microbiome in SARS-CoV-2 infection and transmission in order to develop a therapeutic approach to prevent infection and stop the spread of COVID-19. The role of the oral cavity and oral microbiome in COVID-19 is an important area of investigation. Correlates of disease study revealed that patients with periodontitis have more propensity to severe disease which suggested that the oral microbiome, especially periodontal pathogens may play a role in COVID-19 infection. To address the possible role of the oral microbiome, Cayabyab’s lab isolated oral bacteria from the saliva of 34 healthy volunteers and found that oral bacteria are capable of modulating COVID-19 pseudovirus infection in vitro. Interestingly, oral bacteria isolated directly from human volunteers either had an inhibitory, enhancing or no effect on infection. To identify which oral bacterial species can modulate infection, Cayabyab’s lab tested various non-pathogenic and pathogenic oral bacteria and found that that only certain oral bacteria, especially Porphyromonas gingivalisare capable of inhibiting infection. In the proposed research, our main objective was to identify and characterize anti-COVID-19 factor(s) produced by P. gingivalis. Our preliminary studies showed that P.gingivalis phosphoglycerol dihydroceramide (PGDHC) and unknown factors produced by P. gingivalis were capable of potently inhibiting SARS-CoV-2 pseudovirus infection of ACE2+ cells. Through biochemical studies, we identified the antiviral factor(s) as well as attempted to determine the ability of these P. gingivalis factors to inhibit important SARS-CoV-2 variants in vitro and delineate the mechanistic basis for inhibition.
Promising results from the proposed study would help address the role of the oral microbiome in COVID-19 infection and identify anti-viral factors produced by oral bacteria that could lead to the development of a life-saving therapy for the prevention of COVID-19 infection, which today remains a global public health problem.
NSUWorks Citation
Angel Gonzalez Saez. 2024. The Role of the Oral Microbiome in COVID-19 infection. Capstone. Nova Southeastern University. Retrieved from NSUWorks, Halmos College of Arts and Sciences and the Guy Harvey Oceanographic Research Center. (42)
https://nsuworks.nova.edu/honors_theses/42.