Predictive value of nasal bacterial culture for etiological agents in acute maxillary sinusitis.

Nasal secretion, aspiration yield and lavage content from the sinus were studied for bacteria in 175 patients (247 sinuses) with acute maxillary sinusitis. The same pathogen was cultured from the nose and aspiration fluid in 91% of cases of acute purulent sinusitis. This indicated a significant predictive value of the nasal bacteriological culture for presence of pathogenic bacteria in the sinus in purulent cases. In cases with no growth of pathogens in the aspirate, the nasal culture showed pathogenic bacteria in about 50%. Examination of the aspiration fluid may occasionally give false negative result in purulent maxillary sinusitis (at least 3% in the present series). In these cases, culture of the irrigation yield may prove helpful.