Antimicrobial treatment of sinusitis.

Sinusitis is a common disease. Most cases of acute sinusitis involve the maxillary sinus and occur after viral infections of the upper respiratory tract. The usual pathogens are Streptococcus pneumoniae and Haemophilus influenzae. Moraxella (Branhamella) catarrhalis is also an important pathogen in children. Anaerobic infections are more common in chronic sinusitis. Fungi are frequently observed in granulocytopenic cancer patients but also can occur in apparently normal hosts. Many strains of H influenzae and M catarrhalis observed in patients with sinusitis produce beta-lactamases. Many antimicrobial regimens have proven successful in the treatment of sinusitis, including ampicillin, amoxicillin, trimethoprim-sulfamethoxazole, the tetracyclines, and cefuroxime axetil, but only the latter three drugs are active against most beta-lactamase-producing strains. Nosocomial sinusitis usually occurs in intensive care unit settings and is frequently associated with nasopharyngeal instrumentation. The pathogens observed in nosocomial sinusitis are gram-negative bacilli or staphylococci and frequently require therapy with broad-spectrum penicillins or cephalosporins, an aminoglycoside, or vancomycin.