Current issues on resistance, treatment guidelines, and the appropriate use of fluoroquinolones for respiratory tract infections

Background: Community-acquired respiratory tract infections comprise a large percentage of diseases treated by primary care physicians, and rates of antimicrobial use for respiratory tract infections are increasing. The fluoroquinolones comprise a drug class with broad-spectrum activity against many of the key pathogens associated with community-acquired respiratory tract infections, including Streptococcus pneumoniae, and other significant pathogens, such as Staphylococcus aureus and Pseudomonas aeruginosa. While fluoroquinolones have gained popularity, the settings for their appropriate use in treating respiratory tract infections remain unclear. Objective: In this article, the mechanisms of fluoroquinolone resistance in S pneumoniae, treatment guidelines, and the mode of spread of resistance are reviewed. Methods: The authors conducted a MEDLINE search for articles published from 1990 to the present. Search terms included Streptococcus pneumoniae, fluoroquinolones, and resistance. Articles were selected for inclusion based on their relevance to the objective of this review. Results: Although 3 sets of treatment guidelines for community-acquired pneumonia (CAP) currently exist in the United States, a consensus for the role of fluoroquinolones in the outpatient management of CAP has not been achieved. Factors mitigating for restraint in the outpatient use of fluoroquinolones include concern for the spread of resistance to "innocent-bystander" organisms, such as S aureus and P aeruginosa, as well as possible inappropriate "trickle-down" use for other, less severe respiratory syndromes, such as bronchitis. Conclusion: Although the fluoroquinolones are potent agents against respiratory pathogens and have a clearly defined role in the treatment of hospitalized patients with CAP, their optimal role in the outpatient management of respiratory tract infections remains controversial.