Treatment of chronic and recurrent respiratory infections with intramuscular ceftazidime.

Two groups of patients were treated with ceftazidime intramuscularly for 10 days. There were 34 patients with acute purulent exacerbations of chronic bronchitis of whom 20 received 1-g and the other 142-g injections. A further 38 patients with chronic recurrent respiratory infections (mostly severe bronchiectasis associated with Pseudomonas aeruginosa) were treated with 2-g injections twice or thrice daily. Blood and sputum concentrations of ceftazidime were measured microbiologically on the first day of treatment. The peak serum concentrations (34.4 and 37.8 mg/l after the 2 different doses) were reached between 1/2 and 1 h after the injections and the mean areas under the concentration-time curves were 131 mg/l X h and 149 mg/l X h, respectively. The sputum concentrations after the 2 doses reached 3.0 mg/l after 1 g, and 3.5 mg/l after the 2 g doses. Sputum cultures before and after treatment showed that 32 of the 34 patients with chronic bronchitis had negative cultures at the end of the treatment although 6 had further infections by the 17th study day. Among the 38 patients with relapsing infections with Gram-negative organisms, one died early in the treatment course and one later on, but 28 of the 37 patients had negative sputum cultures on day 11 and 17 of the 36 remaining were clear of infection on day 17. The recurrences were all associated with Ps. aeruginosa or Ps. maltophilia. Some 69% of the 69 Ps. aeruginosa strains were inhibited by 2 mg/l of ceftazidime and 91% by 4 mg/l. All 3 Ps. maltophilia strains were resistant (MICs greater than 32 mg/l).