Airway infection.

Bronchitis in its acute and chronic forms with recurrent acute exacerbations is one of the most common reasons for physician visits, accounting for a significant cost to the health-care system, lost work days, and increased morbidity and mortality. Smoking and recurrent lower respiratory tract infections are major risk factors for chronic bronchitis. Therefore, smoking cessation and vaccination strategies are cornerstones of management in terms of halting disease progression and reducing the frequency of infectious exacerbations. Bacterial infection is the main culprit in acute flares of the disease. Routine antimicrobial therapy fails in a significant number of patients, and therapeutic failures lead to increased costs. Several stratification schemes have been proposed to improve initial antimicrobial selection. These schemes identify patient's age, severity of underlying pulmonary dysfunction, frequency of exacerbations, and the presence of comorbid illnesses as predictors for likely pathogens and to guide antimicrobial selection. This approach may reduce the risk for treatment failure, which would have significant medical and economic implications. Improved understanding of the roles of airway inflammation and infection in the pathogenesis of progressive airway disease, in addition to future studies examining the efficacy of newer classes of antimicrobials, should guide physicians to target early and effective treatment to high-risk patients.