Barriers to the effective management of respiratory tract infections in the community

Abstract

The treatment of respiratory tract infections (RTIs) continues to challenge the knowledgeable and conscientious physician. Upper RTIs such as sinusitis and tonsillitis/pharyngitis - while not generally life-threatening - are associated with personal cost and suffering, while infections of the lower respiratory tract, including community-acquired pneumonia (CAP) and acute exacerbations of chronic bronchitis (AECB), represent a more serious clinical challenge and account for almost half of all community-acquired infections. Moreover, such infections may be fatal. Laboratory tests for etiologic agents of RTIs are often insensitive and slow and identify the causative pathogen in only a minority of cases. Therapy for RTIs is, therefore, generally presumptive and instituted before there is a clear understanding of etiology. Such an approach requires antibacterials that possess a spectrum of activity which covers both the common and atypical/intracellular pathogens associated with RTIs to enable physicians to confidently prescribe treatment. A major barrier to the confident prescribing of empiric therapies for RTIs is the increasing prevalence of resistance to existing antibacterial agents among respiratory tract pathogens. Increasing levels of antibacterial resistance now threaten the utility of existing agents, primarily the beta-lactams and macrolides, and continue to drive the search for newer agents which retain activity against drug-resistant respiratory tract pathogens. This need is emphasized by recent evidence that bacterial resistance may be associated with poorer clinical outcomes, particularly for patients with severe infections. There is enormous concern and uncertainty about the factors that contribute to increasing bacterial resistance and treatment strategies that should be adopted to minimize this problem. The arguments have raged particularly around recent Infectious Diseases Society of America (IDSA) guidelines on the treatment of CAP, which have advocated a greater role for fluoroquinolones. One school of thought - driven in part by concerns over cost of therapy - advocates the use of older agents such as amoxicillin, in the hope that any resistance that is incurred will be to these agents, leaving the newer agents for select cases with acquired resistance. Advocates of the newer agents argue that this approach represents a false economy and that there is a greater likelihood of first-line success with newer agents, so that patients are less likely to require a second physician visit and a second course of antibacterial therapy.