Detection and quantification of Staphylococcus in chronic rhinosinusitis

Area of Science:

• Microbiology
• Genetics
• Bioinformatics

Background:

• The sinonasal microbiota plays a role in chronic rhinosinusitis (CRS) pathogenesis, with Staphylococcus aureus often implicated.
• Staphylococcus epidermidis, another common sinonasal bacterium, may inhibit S. aureus colonization, suggesting a complex microbial interaction in CRS.

Purpose of the Study:

• To develop and validate specific polymerase chain reaction (PCR) primer pairs for quantifying S. aureus and S. epidermidis absolute abundances.
• To compare the bacterial community composition and absolute abundances of S. aureus and S. epidermidis in patients with CRS and healthy controls.

Main Methods:

• Six candidate Staphylococcus species-specific primer pairs were evaluated in silico and in vitro.
• Quantitative PCR (qPCR) was used to determine the absolute quantification of S. aureus, S. epidermidis, and total bacterial load in 40 CRS patients and 14 controls.
• Amplicon sequencing of the 16S rRNA gene's V3-V4 hypervariable regions was performed to analyze bacterial community composition.

Main Results:

• Primer pairs targeting the S. aureus gmk gene and S. epidermidis nrd gene demonstrated optimal specificity and sensitivity.
• S. aureus and S. epidermidis were highly prevalent in all groups (CRS without nasal polyposis, CRS with nasal polyposis, and controls), with occurrence rates exceeding 80% for S. aureus and 95% for S. epidermidis in CRS patients.
• Patients with CRS (both CRSsNP and CRSwNP) exhibited a significantly higher overall bacterial load compared to controls (p < 0.05).

Conclusions:

• The study successfully identified specific primer pairs capable of differentiating S. aureus and S. epidermidis, overcoming limitations of standard sequencing methods.
• A very high prevalence of S. aureus was observed in both CRS patients and control individuals, suggesting its widespread presence in the sinonasal environment.
• While S. aureus and S. epidermidis are prevalent, no significant correlation was found between their individual abundances in this cohort.