Widespread use of antibiotics in agriculture, increased antibiotic use in children and excessive use of antibiotics in adults have caused an increase in antibiotic-resistant organisms in the past decade. To address this issue, the Centers for Disease Control and Prevention (CDC) assembled a panel of national health experts, including physicians with expertise in internal, family, emergency and infectious diseases medicine, to develop evidencebased guidelines for evaluating and treating adults with acute respiratory illness. The goal of the guidelines put together by the CDC and other members of the panel is to provide physicians with practical strategies for limiting antibiotic use to patients who are most likely to benefit. The complete treatment guidelines were published in the March 20, 2001 issue of Annals of Internal Medicine, and they can be viewed online at http://www.annals.org/issues/v134n6/full/200103200-00013.html.

Antibiotics are frequently prescribed for uncomplicated respiratory tract infections. These infections are the second leading condition for which antibiotics are prescribed each year, and they account for 10 percent of all prescriptions annually in ambulatory practice. Physicians have reported that unrealistic patient expectations, patient pressure to prescribe antibiotics and insufficient time to educate patients about the ineffectiveness of antibiotics are some of the reasons that so many prescriptions are written.

Clinical presentation also affects the decision to prescribe an antibiotic. Physicians identify and treat a subset of upper respiratory tract infections primarily characterized by the presence of purulent manifestations. Purulent or green nasal discharge, production of green phlegm, presence of tonsillar exudate and current tobacco use are independent predictors of antibiotic treatment. The more of these factors that are present, the more likely the physician is to prescribe an antibiotic.

The urgency of limiting antibiotic use in ambulatory practice has been fueled by the epidemic increase in antibiotic-resistant Streptococcus pneumoniae, which causes community-acquired bacterial pneumonia, bacterial meningitis, bacterial sinusitis and otitis media. Previous antibiotic use is the most important factor in carriage of and infection with antibiotic-resistant S. pneumoniae. Beyond reducing costs for patients and payers and the risk of side effects, reducing antibiotic use in the community will decrease the number of common antibiotic-resistant pathogens.

Recommendations

These recommendations apply only to immunocompetent adults with no important comorbid conditions, such as pulmonary or cardiac disease. Along with these guidelines, patient education is fundamental to decreasing unnecessary prescriptions.

• In previously healthy adults, the diagnosis of nonspecific upper respiratory tract infection should be used to denote an acute infection that is typically viral in origin and in which sinus, pharyngeal and lower airway symptoms, although frequently present, are not prominent. Most cases of uncomplicated upper respiratory tract infection in adults resolve spontaneously. Symptoms typically last one to two weeks, and most patients feel better within the first week. These infections are predominantly viral in origin, and complications, such as bacterial rhinosinusitis or bacterial pneumonia, are rare.

• Antibiotic treatment of adults with nonspecific upper respiratory tract infection is not recommended because it does not enhance illness resolution or alter the rates of uncommon complications.

• Purulent nasal discharge and sputum do not predict bacterial infection and patients with these symptoms do not benefit from antibiotic treatment. Antibiotic therapy does not decrease the duration of symptoms or lost work time, or prevent complications.