Bacteriological findings of acute maxillary sinusitis in young adults.

Bacteriological findings in 339 sinus secretions obtained by puncture were investigated in 238 young adult patients with acute maxillary sinusitis. Aerobic and anaerobic cultures were performed immediately. A total of 76% of the secretions were positive. The most common pathogens isolated were Haemophilus influenzae (50%), Streptococcus pneumoniae (19%), Streptococcus pyogenes (5%), and Branhamella catarrhalis (2%). Coagulase-negative staphylococci and Staphylococcus aureus were isolated in 8 and 1% of the specimens, respectively. The staphylococci were almost invariably present in low numbers and, therefore, probably represented nasal contamination. Other aerobic species were found only occasionally. Anaerobes were isolated in 5% of the secretions. In one-half of these, a low concentration of Propionibacterium acnes was the sole anaerobe that was found, and it was usually mixed with a facultative organism (suggestive of contamination with nasal flora). Only 2% of the sinuses were considered to have true anaerobic infections (high concentrations of several species typical of anaerobic infection), indicating that anaerobes are not a significant cause of acute maxillary sinusitis in a young adult population. The high recovery of H. influenzae in this study indicates that aminopenicillins may be more appropriate choice than conventional penicillin in the antimicrobial therapy of acute maxillary sinusitis (only 2 of 168 H. influenzae strains produced beta-lactamase).