Amarh, Elizabeth
(2024)
Bacteriophage Susceptibility and Genomic Analyses of Rapidly Growing and Slowly Growing Clinically Isolated Non-Tuberculous Mycobacteria.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Non-tuberculous mycobacteria (NTM) cause pulmonary and disseminated infections that are difficult to treat with antibiotics. A renewed interest in phage therapy has yielded positive results in treating antibiotic resistant bacterial infections, including in NTM infections. Mycobacteriophage therapy has been well-documented, with over twenty published cases and zero adverse reactions to treatment. The number of phages that can be applied therapeutically is < 10, and this may be influenced by the host used to isolate most of the over 13,000 mycobacteriophages in the inventory. Most phages are temperate, with the ability to form a prophage in the genome of a susceptible host. The genomes of clinically isolated NTM species are replete with intact prophage sequences. These prophages can be induced to excise from the host genome, re-circularizing the phage genome, and producing phage particles (lytically propagated spontaneously induced prophages (LPSIPs)). We hypothesize these LPSIPs may demonstrate a host range more inclusive of clinically isolated NTM species, as their presence in the NTM genomes suggests they are able to temperately infect clinically isolated NTM successfully. The goal of this research is to increase the repertoire of therapeutically useful phage, by propagating LPSIPs from clinically isolated NTM strains, and generating a lytic mutant of the temperate LPSIP. So far, no LPSIPs isolated from pathogenic NTM infect the non-pathogenic M. smegmatis mc2155. Because usual methods of phage engineering, BRED and CRISPY-BRED, are not available in NTM other than M. smegmatis mc2155, CRISPR-Cas9 instead was implemented. Through characterizing clinically isolated NTM strains phenotypically, assessing the genomes for prophage content, isolating the prophage in LPSIP form, and using CRISPR-Cas9 to engineer a LPSIP lytic mutant, this work expands the repertoire of therapeutically useful mycobacteriophages.
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Details
| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
27 August 2024 |
| Date Type: |
Publication |
| Defense Date: |
26 April 2024 |
| Approval Date: |
27 August 2024 |
| Submission Date: |
2 August 2024 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
164 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Biological Sciences |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
bacteriophage, non-tuberculous mycobacteria, genomics, phage therapy, abscessus, avium |
| Date Deposited: |
27 Aug 2024 13:10 |
| Last Modified: |
27 Aug 2024 13:10 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/46081 |
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