A Comparison of the Bacterial Culture Results of Maxillary Sinus Mucosa and Pus Collections for Chronic Maxillary Rhinosinusitis

Abstract

Objective: Although maxillary antral taps are the standard for collecting pus for bacterial culture, they sometimes
reveal no growth. Intraoperative mucosal cultures are another method to collect pathogen samples. This study
compared aerobic bacterial cultures from maxillary sinus mucosa and pus collected from chronic maxillary
rhinosinusitis patients.
Methods: A prospective study of 22 chronic maxillary rhinosinusitis patients was conducted. Antral pus and mucosa
collected during endoscopic sinus surgery were immediately sent to a microbiological laboratory. The degree of
concordance between maxillary sinus mucosa aerobic bacterial cultures and pus cultures was then analyzed.
Results: Twenty-seven specimens were obtained for the cultures. The proportions of positive mucosal and pus
cultures were 40.74% and 51.85%, respectively. The common aerobic pathogens from the two culture techniques
were Pseudomonas aeruginosa and Staphylococcus aureus. A concordance between the pus and mucosal cultures
was demonstrated by 19 out of 27 specimens (70.37%). Compared with the pus cultures, the mucosal cultures had
a specificity of 84.62% (95% CI, 54.55%-98.08%), a sensitivity of 57.14% (95% CI, 28.86%-82.34%), a predictive
value of a positive result of 80% (95% CI, 50.83%-93.93%), and a predictive value of a negative result of 64.71%
(95% CI, 48.96%-77.80%).
Conclusion: Similar pathogenic bacteria were recovered from the mucosa and pus. Given the high degree of
similarity of the bacteria found, the good concordance rate, and the high specificity and positive predictive value
of the mucosal cultures compared with the pus cultures, mucosal cultures should be a reference standard and an
option when pus is unavailable, especially with immunocompromised patients.