Chronic sinusitis in children and adults: role of bacteria and antimicrobial management.

The nasopharynx serves as the reservoir for anaerobic bacteria as well as pathogenic bacteria that can cause respiratory infections including sinusitis. Some of these organisms possess the ability to interfere with the growth of potential pathogens and may play a role in preventing infections. Anaerobic bacteria emerge as pathogens as the infection becomes chronic. This may result from the selective pressure of antimicrobial agents that enable resistant anaerobic organisms to survive, and from the development of conditions appropriate for anaerobic growth, which include the reduction in oxygen tension and an increase in acidity within the sinus. Anaerobes were identified in chronic sinusitis in adults and children whenever techniques for their cultivation were employed. The predominant isolates were pigmented Prevotella, Fusobacterium, and Peptostreptococcus spp. The choice of antimicrobial agent in chronic sinusitis should provide coverage for the usual pathogens in acute sinusitis as well as beta-lactamase-producing aerobic and anaerobic organisms.