Anaerobic bacteria in upper respiratory tract and other head and neck infections.

Anaerobic bacteria are common in chronic upper respiratory tract and head and neck infections. Anaerobes are the most predominant components of the normal human oropharyngeal bacterial flora, and are therefore a common cause of bacterial infections of the upper respiratory tract that are of endogenous origin. Because of their fastidious nature, anaerobes are difficult to isolate from infectious sites and are often overlooked. Anaerobic bacteria can be recovered in chronic otitis media and sinusitis, and play a role in tonsillitis. They are also important in complications of these infections. Anaerobes predominate in deep oral and neck infections and abscesses. In addition to their direct pathogenicity in these infections, they possess an indirect role through their ability to produce the enzyme beta-lactamase. In this fashion, they are capable of "shielding" non-beta-lactamase-producing bacteria from penicillins. The lack of directing adequate therapy against these organisms may lead to clinical failures. Their isolation requires appropriate methods of collection, transportation, and cultivation of specimens. Treatment of anaerobic infections is complicated by the slow growth of these organisms, by their polymicrobial nature, and by the growing resistance of anaerobic bacteria to antimicrobials. Antimicrobial therapy is often the only form of therapy required, whereas in other cases, it is an important adjunct to a surgical approach. Because anaerobic bacteria generally are recovered mixed with aerobic organisms, the choice of appropriate antimicrobial agents should provide for adequate coverage of both types of pathogens.