# Nasopharyngeal Staphylococcus aureus Isolation and Bacterial Culture Profiles in COVID-19 Patients: A Comparative Study Based on Lung Involvement

## TL;DR

This study examined whether Staphylococcus aureus and other bacteria in the nose differ in people with and without lung-affected COVID-19, but found no significant differences.

## Contribution

The study provides new insights into bacterial carriage in early-stage COVID-19 patients, focusing on nasopharyngeal S. aureus and lung involvement.

## Key findings

- Staphylococcus aureus was isolated in 21.6% of COVID-19 patients and 35.7% of controls, with no significant difference.
- No statistically significant differences were found in bacterial profiles between groups with or without lung involvement.
- The clinical relevance of S. aureus colonization in early-stage COVID-19 remains unclear.

## Abstract

Purpose: This exploratory study aimed to determine the nasopharyngeal carriage rate of Staphylococcus aureus and to characterize the distribution of other culturable bacterial species in patients with COVID-19. Additionally, we assessed whether bacterial growth patterns differed between patients with and without lung involvement.

Methods: Nasopharyngeal samples were collected from COVID-19 patients with and without lung involvement, as assessed by thoracic CT scans. The study also included PCR-negative control patients. Sampling occurred between January and March 2021 at a state hospital outpatient clinic. A total of 65 participants were included in the study: 51 (78.5%) tested positive for COVID-19, of whom 25 (49.0%) had lung involvement and 26 (51.0%) did not. The remaining 14 (21.5%) served as PCR-negative controls.

Results: S. aureus was isolated in 11 (21.6%) of COVID-19-positive patients and 5 (35.7%) of controls. Among COVID-19 patients, the isolation rate was 6 (24.0%) in those with lung involvement and 5 (19.2%) in those without. No statistically significant differences were observed in S. aureus carriage or in the overall bacterial profiles across the groups.

Conclusion: Nasopharyngeal S. aureus colonization and bacterial distribution showed no significant association with COVID-19 status or lung involvement. Although colonization is common, its clinical relevance in early-stage COVID-19 remains unclear and warrants further study.