Activity of ceftazidime against Pseudomonas aeruginosa from bacteraemic and fibrocystic patients.
Minimum inhibitory and bactericidal levels of ceftazidime were determined for 337 isolates of Pseudomonas aeruginosa (135 mucoid, 202 non-mucoid) derived from fibrocystic patients, and 102 isolates of Ps. aeruginosa from blood or CSF. Fifty per cent of isolates of Pq. aeruginosa from all sources were inhibited by 2 mg/l of ceftazidime using inocula of 10(5)-10(6) colony forming units. Ninety per cent of the blood-culture and mucoid isolates were inhibited by 4 mg/l of ceftazidime, but more than 10 mg/l was required to inhibit 90% of the non-mucoid organisms. Bactericidal levels were close to the inhibitory levels. Of 30-isolates of Ps. cepacia, 50% were inhibited by 2 mg/l, and 90% by 4 mg/l of ceftazidime. Strains of pseudomonas derived from patients with fibrocystic disease were less susceptible than the strains from bacteraemic patients. Of the former, the mucoid strains were more susceptible than the non-mucoid strains. The patients with cystic fibrosis had been exposed to beta-lactam drugs for many years.
Department of Bacteriology and the Research Institute The Hospital for Sick Children, Toronto, Canada.
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Fleming
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Knie
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000382:microbiology*; D016956:Burkholderia cepacia / Q000187:drug effects; D002442:Ceftazidime / Q000494:pharmacology*; D002648:Child; D003550:Cystic Fibrosis / Q000150:complications / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests; D011552:Pseudomonas Infections / Q000150:complications / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects*
D000900:Anti-Bacterial Agents; D002442:Ceftazidime