Date of Award

2021

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Microbiology and Immunology

Abstract

The urinary tract contains a community of bacteria called the urinary microbiota (urobiota) thatmay be relevant to health; the genomic component of the urobiota is the urinary microbiome (urobiome). Urinary bacteria have been associated with both asymptomatic states and disease conditions, such as urinary tract infection (UTI), overactive bladder (OAB), and urge urinary incontinence (UUI). Some bacteria, such as E. coli, are considered urinary pathogens (uropathogens) but also can be commensals. Bacteriophage (phage) are ubiquitous in nature and likely shape bacterial populations in every niche; thus, phage may be one factor that modulates the urobiota. Phages have a specific host range dictated not just by host receptor compatibility, but also by traits of the bacterial host. To understand the genetic determinants of phage infection in urinary bacteria, we have used a model system consisting of urinary E. coli and the lytic E. coli phages (coliphages). Urinary E. coli that are less permissive to coliphage infection often carry plasmid-related genes. To determine whether these genes relate to permissivity, plasmids present in urinary microbiota (UMB) were conjugated into a naïve E. coli K-12 background; E. coli K-12 acquisition of F plasmids from urinary isolates UMB0928 and UMB1284 decreased permissivity to infection by the lytic coliphages P1vir, Greed, and Lust. Analysis of the plasmidome of urinary E. coli indicated that more than half of these isolates are predicted to contain a plasmid; most of these urinary plasmids are of the F plasmid group. Antibiotic resistance and virulence genes were common in F plasmids. The F plasmids pU0928 and pU1284 reduced permissiveness to phage in E. coli K-12. These two plasmids were stable and conferred multiple antibiotic resistances

Given the selective pressure imposed by the rapid propagation and evolution of phages,plasmids could be a vehicle to deliver and maintain anti-phage genes in a bacteria population. Phage selective pressure also could result in the acquisition and maintenance of plasmid-linked content, such as genes for antibiotic resistance and virulence factors. Urinary bacteria, phage, and plasmid dynamics could be important for clinically relevant traits of urinary bacteria and overall urobiota dynamics.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

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