Does monotherapy of pulmonary infections in cystic fibrosis lead to early development of resistant strains of Pseudomonas aeruginosa?

We report the development of ceftazidime-resistant strains of Pseudomonas aeruginosa in a small population of cystic fibrosis patients who had ceftazidime monotherapy over a 5-year period as clinically indicated. The background rate of less than 30% of patients with a ceftazidime-resistant strain of P. aeruginosa in their sputum each month is similar to the resistance rate to other anti-pseudomonas antibiotics that have seldom been used here. In practice this resistance has meant that for about 10% of patients each month consideration has to be given to the use of an agent other than ceftazidime.