Molecular characteristics of Staphylococcus aureus associated with chronic rhinosinusitis

The anterior nares have been regarded as the major carriage site of Staphylococcus aureus. From here, the organism can spread to other parts of the body where it might act as harmless commensal or cause mild to severe infections. Nasal sinuses are normally sterile, but in patients with chronic rhinosinusitis (CRS), the finding of S.aureus in maxillary sinus cultures is common. Isolates were obtained from the nares and maxillary sinus of patients with CRS and the nares of healthy controls. A significantly higher frequency of S.aureus was found in nares samples from patients (24/42) compared to controls (16/57) (p=0.004). There is no consensus regarding whether S.aureus is a relevant pathogen in CRS. A DNA microarray was used to investigate the prevalence of S.aureus virulence genes with focus on staphylococcal enterotoxins, toxic shock syndrome toxin-1, agr types, and cell wall-associated proteins. The genotyping of S.aureus isolates revealed only small and non-significant differences in gene prevalence between isolates collected from patients with CRS and those collected from healthy nasal carriers. This study provides an increased knowledge of the genetic pattern of virulence genes among S.aureus collected in CRS.