Comparison of endoscopically-guided swab vs aspirate culture techniques in post-endoscopic sinus surgery patients: Blinded, prospective analysis

Background: Culture-directed antibiotic therapy remains imperative in the management paradigm of chronic rhinosinusitis (CRS). The objective of this study was to conduct a prospective, blinded comparison of endoscopically-guided swab and aspirate cultures from the same sinonasal site in patients presenting with acute infectious exacerbations post-sinus surgery. Methods: Forty-nine CRS patients were prospectively enrolled in a tertiary care rhinology clinic. At the conclusion of the study, all cultures were unblinded to determine mean culture yield, most common pathogens, potential contaminants, and therapeutic correlation. Results: The mean patient age was 49 years and 40.8% were males. All patients had evidence of symptomatic exacerbation with purulence on endoscopy at the time of presentation. There was a mean of 1.367 pathogens assayed per aspirate culture vs a mean of 1.102 per swab culture (p = 0.0032). The prevalence of Pseudomonas aeruginosa was 42% for aspirate vs 30% for swab cultures, respectively. The prevalence of Staphylococcus aureus was 49% for suction cultures vs 45% for swab cultures. There were 9 and 11 likely contaminants using aspirate and swab cultures, respectively. Therapeutic correlation was strong in 67%, moderate in 18%, and weak in 14% of patients. Conclusion: This prospective analysis demonstrated higher culture yield, particularly with Pseudomonas, with aspirate vs swab cultures in postoperative patients. There is a strong clinical correlation between the 2 methods, and both aspirate and swab techniques serve as acceptable alternatives for endoscopic-guided cultures in patients with post-functional endoscopic sinus surgery infectious exacerbations.