Antibiotic resistance of oral anaerobic bacteria and their effect on the management of upper respiratory tract and head and neck infections.

Anaerobes of oral origin are common in chronic upper respiratory tract and other head and neck infections. Anaerobes are the predominant components of the normal human oropharyngeal flora, and are therefore a common cause of bacterial infections of the upper respiratory tract that are of endogenous origin. These bacteria can be isolated in chronic otitis media, sinusitis, and tonsillitis, and their complications. Anaerobes also predominate in deep oral and neck infections and abscesses. Their isolation requires appropriate methods of collection, transportation, and cultivation of specimens. In addition to their active pathogenic role in these infections, many anaerobes express an indirect effect through their ability to produce the enzyme beta-lactamase. This enables these organisms to shield non-beta-lactamase-producing bacteria (BLPB) from penicillins. Inadequate therapy against BLPB may lead to clinical failures. Treatment of anaerobic infection is complicated by their slow growth, their polymicrobial nature, and the growing resistance of anaerobic bacteria to antimicrobials. Antimicrobial therapy is often the only form of therapy needed, whereas in other instances it is an important adjunct to a surgical approach. Because anaerobes generally are isolated mixed with aerobic organisms, therapy should provide for adequate coverage of both types of pathogens.