# Nasal Staphylococcus aureus in COVID-19 Patients Shows No Enrichment of High-Risk Clones

## TL;DR

The study found that S. aureus in the noses of hospitalized COVID-19 patients are not more dangerous or drug-resistant than usual.

## Contribution

The study shows no selective enrichment of high-risk S. aureus clones in COVID-19 patients.

## Key findings

- Only 6.4% of S. aureus isolates from COVID-19 patients were methicillin resistant.
- Most isolates showed limited antimicrobial resistance beyond MLSB phenotype.
- Genetic diversity was high with no dominant clone identified.

## Abstract

Staphylococcus aureus nasal carriage is a potential source of secondary infections in COVID-19 patients, yet it remains unclear whether SARS-CoV-2 infection favors colonization by more virulent or resistant strains. We analyzed 31 nasal S. aureus isolates from hospitalized COVID-19 patients to assess antimicrobial resistance, virulence gene content, and genetic diversity. Only two isolates (6.4%) were methicillin resistant, and most strains showed limited resistance beyond the MLSB phenotype. Adhesin genes were highly prevalent, whereas toxin genes were detected in only 16.1% of isolates. Spa typing revealed high genetic diversity with no dominant clone. Overall, S. aureus isolates from COVID-19 patients did not differ substantially from previously described carriage strains, suggesting no selective enrichment of highly virulent or resistant lineages during SARS-CoV-2 infection.