Abstract

Staphylococcus aureus has an historical relationship with anthropogenic environments, particularly hospitals, where infection characteristics differ from community-acquired disease. This has promoted a designation of strains as healthcare or community associated. Despite this affiliation, genetic approaches have failed to support these groupings. In order to establish the genetic relationship between S. aureus from differing anthropogenic environments, I have analyzed the relatedness between three cohorts of S. aureus: nasal carriage isolates from community participants, infectious isolates from hospitals, and a cohort from an uninvestigated environment, an ambulatory clinic. Multilocus Sequence Typing (MLST) and Staphylococcus aureus protein a (spa) repeat regions were analyzed and the genetic relationships between cohorts at these sites were determined. I found high similarity in recovered sequences within and between all cohorts, with cohorts sharing 100% sequence identity across some samples. Phylogenetic reconstruction of the combined datasets indicate panmixia, with samples of all origins belonging to shared genetic lineages. Additional clustering algorithms supported this pattern. The findings of this study indicate that there is strong genetic similarity between both infectious strains and nasal carriage strains and between isolates from all cohorts. This research has implications for healthcare, as it demonstrates that S. aureus from differing environments are genetically similar (often identical), cautioning against delineating strains into nasal carriage or infectious based on origin. This research also informs the study of S. aureus evolution – strengthening the conclusion that differentiation at stably selected markers in lineages within differing 'healthcare habitats' is insufficient to explain observed phenotypic differences, and alternative explanations must be explored.

Graduation Date

2016

Semester

Spring

Advisor

Parkinson, Christopher

Degree

Master of Science (M.S.)

College

College of Sciences

Department

Biology

Degree Program

Biology

Format

application/pdf

Identifier

CFE0006534

URL

http://purl.fcla.edu/fcla/etd/CFE0006534

Language

English

Release Date

November 2017

Length of Campus-only Access

1 year

Access Status

Masters Thesis (Campus-only Access)

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