Bacteriology of maxillary sinusitis in relation to character of inflammation and prior treatment.

By antral aspiration, 200 sinus secretions were obtained from the same number of adult patients with maxillary sinusitis. The bacteriological findings were related to the character of the secretions as well as to the duration of symptoms, previous antibacterial treatment and possible dental genesis. Pathogens were isolated in 87% of 54 patients with untreated acute sinus empyema, Streptococcus pneumoniae being the most prevalent (57%). In 47 cases of treatment failure Haemophilus influenzae predominated and was found in 60% of the purulent secretions. In all, 11% of the 47 cases showed growth of beta-lactamase-producing H. influenzae, corresponding to 18% of all H. influenzae in this group. Staphylococcus aureus and anaerobic bacteria were infrequent findings except in purulent sinus secretion from patients with a long history. In contrast to patients with sinus empyema, no pathogens were found in the majority of 37 patients with non-purulent sinusitis.