Diagnosis and management of anaerobic infections of the head and neck.

Anaerobic bacteria are important pathogens in head and neck infections such as chronic otitis media, chronic sinusitis, chronic mastoiditis, head and neck abscesses, cervical adenitis, parotitis, and postoperative infection. Bacteroides sp (Bacteroides melaninogenicus group, Bacteroides oralis, and Bacteroides fragilis group), Peptostreptococcus sp, and Fusobacterium sp predominate. The observed recent increase in the number of beta-lactamase-producing strains of Bacteroides sp isolated in head and neck infections has been associated with increased failure rates of the penicillins in the management of these infections. The pathogenicity of these organisms is expressed through their ability not only to survive penicillin therapy but also to shield penicillin-susceptible pathogens from the drug. Because of these direct and indirect virulent characteristics of anaerobic bacteria, appropriate antimicrobial therapy must be directed against all pathogens in mixed infections.