Question 9

What impact does resistance patterns among respiratory tract infection (RTI) pathogens have on the use of fluoroquinolones such as levofloxacin?

Clinical failures have been described among patients with community-acquired pneumonia (CAP) treated with macrolides caused by macrolide-resistant strains of S. pneumoniae (13-16). Rare cases of clinical failure have been seen among community-acquired patients with quinolone-resistant strains of S. pneumoniae treated with low doses of fluoroquinolones. Among patients with CAP, pneumococcal resistance to β-lactams has not been associated with clinical failure (with the possible exception of cefuroxime). These observations have led to the recommendation that antibiotic class should be changed if a patient has received an antibiotic within three months of the current infection. While these recommendations pertain to CAP, it seems prudent to apply them to patients with ABECB although a systemic study of the effect of resistance on outcome has not been performed.