The role of fluoroquinolones in respiratory tract infections.

Quinolones, because of their excellent pharmacokinetic properties, high antimicrobial activity and low incidence of side-effects, have been broadly accepted for the treatment of many infections. Because of perceived limitations against Streptococcus pneumoniae and methicillin-resistant Staphylococcus aureus there has been some reluctance to use them for respiratory tract infections. Ciprofloxacin is the drug of choice for malignant external otitis, a disease caused by Pseudomonas aeruginosa, and it has also been used successfully for the treatment of chronic otitis media where P. aeruginosa, S. aureus and Proteus mirabilis are main pathogens. Quinolones are as efficacious as the beta-lactams and cephalosporins in the treatment of acute sinusitis but most clinicians will not use quinolones for this indication. Acute bacterial exacerbations of chronic bronchitis respond to antimicrobial therapy and quinolones have been demonstrated to be at least equivalent to second- and third-generation cephalosporins, co-amoxiclav and beta-lactams. Recently published guidelines in Canada, USA and Great Britain do not recommend quinolones for the treatment of community-acquired pneumonia except for patients with life-threatening disease requiring ICU admission. A quinolone in combination with an aminoglycoside and macrolide is a regimen that can be used as initial empirical therapy until the results of microbiological investigations are available. For patients with severe hospital-acquired pneumonia, where multiply resistant aerobic Gram-negative bacilli are a consideration, a quinolone in combination with an antipseudomonal penicillin or cephalosporin has been recommended. In the absence of P. aeruginosa, monotherapy with a quinolone is at least as effective as third-generation cephalosporins or imipenem. Early switch therapy from parenteral antibiotics to oral fluoroquinolone has been demonstrated to be very successful.