Early antibiotic treatment of pseudomonas aeruginosa colonisation in cystic fibrosis: a critical review of the literature. 
To assess the evidence supporting early antibiotic treatment in asymptomatic cystic fibrosis (CF) patients colonised by Pseudomonas aeruginosa (PA).  We carried out a computerised (Medline, Embase) and hand search of journals for suitable publications.  All English-language clinical studies regarding the efficacy of early antibiotic treatment on PA colonisation in asymptomatic patients were considered.  Each eligible publications fitting these criteria were assessed for the following outcome measures: frequency of positive PA cultures; serum level of precipitating antibodies; lung function; survival; number of hospitalisations; adverse effects and resistance to antibiotics.  Of the 11 studies eventually considered, 3 were randomised-2 versus placebo- and 8 were cohort studies-2 of which had historical controls.  Overall, 309 patients (population range 7-91 patients) were recruited.  There was a high variability between the individual studies for age, outcome measures, duration of follow-up (1 to 44 months) and treatment (three studies used only aerosol tobramycin, one colistin, four aerosol colistin plus oral ciprofloxacin, one used intravenous treatment and two miscellaneous therapy).  An overall evaluation indicated that early antibiotic treatment can reduce the number of positive cultures and the anti-PA antibody titre.  In one study, FEV1 was better in the treated group (oral ciprofloxacin and nebulised colistin) than in historical controls, while in one placebo-controlled trial, no effect on lung function was shown after 1 year of tobramycin inhalation.  Collateral effects and bacterial resistance were not increased.  The short follow-up did not allow definite conclusions with regard to the long-term progression of respiratory insufficiency or survival.  Evidence was found that antibiotic treatment can reduce the rate of positive cultures and of anti-PA antibody titres in asymptomatic CF patients with newly isolated PA.  Different therapeutic options have not been directly compared: a multi-centre comparative study needs to be carried out.