1983 Volume 31 Issue Supplement3 Pages 434-447
The laboratory and clinical studies on ceftazidime (CAZ), a new broad-spectrum cephalosporin antibiotics with antipseudomonal activity and high stability to a wide range of β-lactamases, were performed in the lower respiratory tract infections.
The in. viitro antibacterial activities of CAZ against respiratory pathogens were measured as the MICs values (inoculum size: 106 cfu/ml). The peak MICs of CAZ were 0.1μg/ml against Streptococcus pneumoniae, 0.2μg/ml against Haemophilus influenzae, 0.2μg/ml against Klebsiella pneumoniae and 3.13μg/ml against Pseudomonas aeruginosa. For the purpose of clarifying β-lactamase stability, antibacterial activities against β-lactamase-producing Haemophilus influenzae (ampicillin-resistant, 2 strains) and Branhamella, catarrhalis (8 strains) were assessed. Against the former, ceftazidime had almost similar activity of ampicillin susceptible strains, but most of the latter were resistant to ceftazidime. By the method of checker board dilution, synergistic effects of ceftazidime with gentamicin could be demonstrated against Pseudomonas maltophilia.
After intravenous instillation of 1 and 2 g ceftazidime over a one hour period, peak serum concentrations in patients with respiratory infections were 105.1μg/ml and 184.5μ/ml, respectively. The ratios of maximum sputum level to peak serum concentration ranged from 0.46% to 7.37%(mean 2.00%). In a patient with chronic bronchitis, ratio of maximum intrabronchiolar secretion level to peak serum concentration was 3.32%.
Eighteen patients with respiratory infections (pneumonia; 4, lung abscess; 1, chronic bronchitis; 6, chronic bronchiolitis; 3, bronchiectasis; 2, secondary bronchitis; 2) were treated with ceftazidime. The clinical effectiveness was 88.9%, and it was noteworthy that Pseudomonas aeruginosa was eradicated in 6 of 8 patients. Mild transient eosinophilia was observed in one patient.
On the basis of these results, it is concluded that ceftazidime is one of the most effective and useful antibiotics for the treatment of respiratory tract infections, particularly those due to Pseudomonas aeruginosa.
