Study objectives: To compare the susceptibility of respiratory cultures of Pseudomonas aeruginosa obtained from patients with cystic fibrosis to cefepime versus ceftazidime. The pattern of cumulative resistance of P aeruginosa to cefepime in patients who had received at least one treatment course of cefepime between two sputum cultures was also characterized.
Design: Prospective consecutive data collection.
Setting: University-affiliated cystic fibrosis clinic and medical center.
Patients: Eighty patients with cystic fibrosis who had at least one sputum culture positive for P aeruginosa with reported microbiologic susceptibilities to cefepime and ceftazidime.
Intervention: Patient data was collected and analyzed. Measurements and Main Results. Two hundred and thirty-one P aeruginosa isolates were collected over 6 months. A total of 16.4% and 8.7% of the isolates were nonsusceptible to cefepime and ceftazidime, respectively (p=0.01). In eight patients who had not received cefepime before the study period, nonsusceptibility was 11.8% and 27.2% before and after exposure to cefepime, respectively.
Conclusions: Susceptibility of P. aeruginosa isolates in patients with cystic fibrosis was lower with cefepime than with ceftazidime. Follow-up surveillance to determine changes in susceptibility of P aeruginosa isolates to cefepime is warranted.