Antibiotic therapy against Pseudomonas aeruginosa in cystic fibrosis.

Antibiotic strategies against Pseudomonas aeruginosa infection in cystic fibrosis (CF) patients should consider the natural history of the P. aeruginosa infection, ranging from the first isolation of the germ in the airways to isolation at every microbiological culture, and the patient's clinical condition. Antibiotic treatment against P. aeruginosa given at the time of first isolation may prevent or delay chronic infection. The period of intermittent colonization can be considered the time before the development of mucoid P. aeruginosa phenotype. The optimal treatment strategy in this stage remains unclear in terms of agents used and duration of treatment. To treat acute exacerbation, the authors suggest using intravenous administration of two different classes of antibiotics. Maintenance antibiotics are administered to slow the decline in pulmonary function for P. aeruginosa chronic infection. The meaning of maintenance therapy has changed over time, beginning from intravenous quarterly anti-Pseudomonas antibiotics, irrespective of symptoms, to other strategies such as oral macrolides, ciprofloxacin or inhaled antibiotics (tobramycin and colistin). Aerosol delivery can provide a high concentration at the desired site with minimal absorption and therefore low risk of toxicity. There is scientific evidence that antibiotics are clinically effective in CF patients. Antibiotic selection should be based on periodic isolation and identification of pathogens and antimicrobial susceptibility.