Staphylococcus aureus (SA) is an opportunistic pathogen and a commensal member of the human microbiota that frequently colonizes the upper respiratory tract and skin. While SA can cause disease ranging from minor skin infections to life-threatening septicemia, it can also be carried asymptomatically. As carriage is the most significant risk factor for SA disease, surveillance is important for the prevention of outbreaks in vulnerable communities. Native Americans have a greater risk of infectious disease than the general US population, and Native Americans in the Southwestern United States have been shown to experience high rates of invasive SA disease. Here we explore the dynamics of SA carriage among the Native Americans by performing high density sampling from multiple anatomical sites and whole-genome sequencing on 310 SA isolates across 60 participants. We assess the richness and diversity of SA carriage isolates via differences in multi-locus sequence type (MLST), core-genome single-nucleotide-polymorphisms (SNPs), and gene content. We find that a considerable proportion (41.7%, n=60) of studied SA carriers exhibit co-carriage with multiple distinct SA strains. Among a small number of participants, we further find considerable genetic variation even among SA isolates belonging to the same MLST. Lastly, we find unequal distribution of clonal complex (CC) by body site, suggesting that certain lineages may be adapted to specific anatomical sites. Together, these findings reveal that co-carriage may occur at a higher rate than previously appreciated and contribute to our understanding of SA intrahost diversity during carriage, which has implications for clinical management and epidemiological investigations.
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Master of Science (M.S.)
College of Medicine
Burnett School of Biomedical Sciences
Length of Campus-only Access
Masters Thesis (Open Access)
Webb, Julia, "Intrahost Diversity of Staphylococcus aureus in Carriage among Native Americans" (2022). Electronic Theses and Dissertations, 2020-. 1694.