Identification of Novel Staphylococcus aureus Core and Accessory Virulence Patterns in Chronic Rhinosinusitis

Area of Science:

• Microbiology
• Infectious Diseases
• Genomics

Background:

• Staphylococcus aureus (S. aureus) nasal colonization is prevalent in healthy individuals and chronic rhinosinusitis (CRS) patients.
• Treatment-resistant S. aureus biofilms and intracellular persistence are hallmarks of CRS, necessitating specific virulence factor gene expression.
• Distinct virulence factor profiles in S. aureus isolates may contribute to persistence and intracellular survival in CRS patients.

Purpose of the Study:

• To investigate and compare the virulence factor gene patterns of S. aureus isolates from non-diseased controls, CRS without nasal polyps (CRSsNP), and CRS with nasal polyps (CRSwNP) patients.
• To identify specific virulence factors associated with S. aureus persistence and intracellular survival in the context of CRS.
• To explore the potential link between S. aureus virulence factor clusters and antibiotic resistance in CRS.

Main Methods:

• Whole-genome sequencing of S. aureus isolates obtained from nasal swabs of 77 individuals (controls, CRSsNP, CRSwNP).
• Analysis of stress, antimicrobial resistance, and virulence genes, including plasmids and prophages.
• Identification and comparison of distinct virulence factor gene patterns across different patient groups.

Main Results:

• Four distinct S. aureus virulence factor gene patterns were identified: a core set common to all isolates and accessory sets including enterotoxin and invasive virulence factors.
• CRSwNP isolates showed incomplete carriage of the core virulence factor set, with significant loss of specific genes like scn, icaC, and hlgA.
• A statistically significant association (p = 0.001) was observed between certain virulence factor gene clusters and patient groups.

Conclusions:

• S. aureus exhibits clustered virulence factors that likely cooperate to enhance bacterial survival, persistence, and pathogenicity.
• The observed differences in virulence factor gene patterns, particularly in CRSwNP isolates, may explain treatment resistance and refractoriness to antibiotics in CRS.
• Understanding these virulence factor dynamics is crucial for developing targeted therapies against persistent S. aureus infections in chronic rhinosinusitis.