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Development and Assessment of Intracellular Infection Models for Staphylococcus aureus
Published on: January 17, 2025
Within-host evolution of Staphylococcus aureus during asymptomatic carriage.
Tanya Golubchik1, Elizabeth M Batty, Ruth R Miller
1Department of Statistics, University of Oxford, Oxford, Oxfordshire, United Kingdom.
Plos One
|May 10, 2013
Summary
Staphylococcus aureus evolution during asymptomatic carriage shows purifying selection and population fluctuations. Understanding this normal state is key to preventing invasive disease progression.
Area of Science:
- Microbiology
- Evolutionary Biology
- Genomics
Background:
- Staphylococcus aureus is a common human commensal and a leading cause of healthcare-associated mortality.
- Understanding within-host evolution of S. aureus during asymptomatic carriage is crucial for elucidating disease progression.
- Approximately one-third of healthy adults carry S. aureus as part of their normal flora.
Purpose of the Study:
- To investigate the evolutionary dynamics of S. aureus during short-term asymptomatic nasal carriage.
- To understand the mechanisms driving bacterial evolution under natural conditions.
- To identify factors contributing to the transition from commensalism to invasive disease.
Main Methods:
- Whole-genome sequencing of 131 S. aureus isolates from 13 colonized hosts.
- Analysis of mutation types (micro and macro), mobile element dynamics, and selection pressures.
- Application of a novel population genetics method to detect host-to-host transmission.
- Quantification of within-host population size fluctuations.
Main Results:
- Purifying selection predominantly shapes the S. aureus fitness landscape, with rare adaptive mutations in surface proteins and enterotoxin genes.
- Significant, hundred-fold fluctuations in within-host bacterial population size were observed, linked to colonization and clearance cycles.
- Evidence of recent transmission between hosts, including within a married couple carrying methicillin-resistant S. aureus (MRSA).
- Characterization of evolutionary processes including point mutations, indels, and mobile element acquisition/loss.
Conclusions:
- This study provides insights into the within-host evolution of S. aureus during its common asymptomatic carriage state.
- Findings serve as a benchmark for future research on the evolution of S. aureus during invasive infections.
- Understanding commensal evolution is vital for developing strategies to prevent S. aureus-related diseases.
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