Microbiology of the Maxillary Sinus in Adults with Chronic Sinus Disease

Antimicrobial therapy is a part of the care of patients with chronic sinus disease (CSD), but the etiologic role of microorganisms in this condition is unclear. Twenty patients with CSD undergoing functional endoscopic sinus surgery who had been off antibiotics for at least 1 week before surgery had a maxillary sinus aspirate for quantitative culture for aerobic bacteria and fungi and a semiquantitative culture from the antrostomy of the same maxillary sinus during endoscopic surgery. Six (30%) of the patients had infection of the maxillary sinus diagnosed by the presence of ≥ 10³ cfu/mL of organisms in the sinus aspirate (Haemophilus influenzae in two patients and one patient each with Moraxella catarrhalis, α-streptococcus, mixed oropharyngeal flora, or Alternaria sp.). All antrostomy specimens obtained by nasal endoscopy during surgery were positive, but the antrostomy cultures did not correlate with the sinus aspirate cultures from the same sinus. Staphylococcus aureus and/or Gram negative rods in eight antrostomy cultures did not predict the presence of these pathogens in any of the maxillary sinus aspirates. Conversely, the bacteria detected with the quantitative aspirate culture in five of the six infected sinuses were not found in the antrostomy specimen; only the fungal sinus infection correlated with the antrostomy culture. Infection of the maxillary sinuses occurred in patients with both limited and severe disease by CT imaging. About one third of patients with CSD necessitating surgery had microbial infection of the maxillary sinus, but antrostomy cultures obtained via endoscopy did not predict the organisms infecting the sinus.