β-Lactamase-Producing Bacteria in Upper Respiratory Tract Infections.

β-Lactamase-producing bacteria (BLPB) can play an important role in respiratory infections. They can have a direct pathogenic impact in causing the infection as well as an indirect effect through their ability to produce the enzyme β-lactamase. BLPB not only may survive penicillin therapy, but as demonstrated by in vitro and in vivo studies, can also protect other penicillin-susceptible bacteria from penicillin by releasing the free enzyme into their environment. The clinical in vitro and in vivo evidence supporting the role of these organisms in the increased failure rate of penicillin in eradication of these infections and the implication of that increased rate on the management of infections is discussed.