Nordstrom, Hayley R
(2022)
Harnessing the diversity of Burkholderia spp. prophages for therapeutic potential.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
Burkholderia is a genus of gram-negative bacteria that naturally reside in the environment. Several species within this genus constitute a major health threat to humans, specifically for people with compromised immune systems or chronic lung diseases such as cystic fibrosis (CF) and chronic granulomatous disease (CGD). Members of Burkholderia are often resistant to antibiotics and infections with these organisms are difficult to treat, particularly those caused by bacteria in the Burkholderia cepacia complex (Bcc). A potential alternative treatment for these resistant infections is bacteriophage (phage) therapy: the therapeutic use of viruses that target bacteria. However, phage therapy is hindered by difficulty in locating bacteriophages that target members of the Burkholderia genus. Bacteriophages incorporated into a cell’s genome, also known as prophages, have been identified within Burkholderia, and may represent a rich source of phages for antimicrobial therapy. The goal of this study was to investigate whether prophages within the genomes of Burkholderia clinical isolates can be harvested and used to kill conspecific and heterospecific species in the genus. Thirty-two Burkholderia isolates were screened for prophage release, and harvested prophages were tested for lytic activity using a plaque assay-based screen against the same 32 Burkholderia isolates. Through all-by-all screening and subsequent whole genome sequencing of phages and host bacteria isolates, we identified and characterized 4 unique bacteriophages of prophage origin. These newly isolated phages were characterized by host-range analysis, whole genome sequencing, and electron microscopy. Several phages showed a range of lytic activity on both conspecific and heterospecific species of Burkholderia. We also analyzed prophage content of 35 Burkholderia clinical isolates and found that each isolate genome encoded between 0-4 different prophages. Some prophages were found to be present in the genomes of multiple isolates of the same species. Finally, while prophage abundance was not associated with phage susceptibility, we did observe that members of B. cenocepacia were more phage susceptible compared to members of B. multivorans. Overall, the data gathered in this study suggest that prophages present within Burkholderia spp. genomes are a potentially useful starting point for the isolation and development of novel bacteriophages for use in phage therapy.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
| Creators | Email | Pitt Username | ORCID  |
|---|
| Nordstrom, Hayley R | han34@pitt.edu | han34 | |
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| ETD Committee: |
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| Date: |
12 May 2022 |
| Date Type: |
Publication |
| Defense Date: |
25 April 2022 |
| Approval Date: |
12 May 2022 |
| Submission Date: |
27 April 2022 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
52 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
School of Public Health > Infectious Diseases and Microbiology |
| Degree: |
MS - Master of Science |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Burkholderia bacteriophage phage prophage cystic fibrosis |
| Date Deposited: |
12 May 2022 13:39 |
| Last Modified: |
12 May 2022 13:39 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/42787 |
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