A double-blind controlled trial of anti-Pseudomonas chemotherapy of acute respiratory exacerbations in patients with cystic fibrosis.

A double-blind controlled trail of anti-Pseudomonas chemotherapy was carried out in 24 exacerbations of pulmonary disease in patients with cystic fibrosis. Fifteen exacerbations were treated with oxacillin plus sisomicin and carbenicillin (treatment group); nine were treated with oxacillin alone (control group). The planned length of treatment was 14 days. The difference between the failure rate in the treatment group (3/15) and the control group (7/9) was statistically significant (P less than 0.015). The difference in improvement of forced expiratory volume in 1 second was also significant (P less than 0.025). At the end of the study, Pseudomonas aeruginosa was still present in the sputum of all nine patients in the control group, but was not isolated from six of the 15 patients in the treatment group. The data suggest a beneficial role for anti-Pseudomonas chemotherapy in the treatment of acute pulmonary exacerbations in patients with cystic fibrosis.