Differences in drug susceptibility between isolates of Pseudomonas cepacia recovered from patients with cystic fibrosis and other sources and its relationship to beta-lactamase focusing pattern.
Pseudomonas cepacia, a significant pulmonary pathogen among children with cystic fibrosis (CF), often possesses an inducible beta-lactamase. The beta-lactamase isoelectric focusing pattern and beta-lactam susceptibility of CF and non-CF isolates of P. cepacia were compared. Against all of the test strains, ceftazidime and piperacillin were more effective than aztreonam. More CF isolates were resistant to 8 micrograms/ml of ceftazidime than non-CF isolates. Isoelectric focusing of cefoxitin-induced, cell-free preparations of the CF isolates produced significantly more bands than comparable preparations of non-CF isolates. Organisms producing a beta-lactamase band that focused in the pH range of 8.5 to 8.7 were significantly more resistant to 8 micrograms/ml of ceftazidime than other isolates. The increased resistance of CF isolates of P. cepacia to ceftazidime may be the result of the production of a specific bacterial beta-lactamase.
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002648:Child; D003550:Cystic Fibrosis / Q000382:microbiology*; D004352:Drug Resistance, Microbial; D006801:Humans; D007525:Isoelectric Focusing; D007527:Isoenzymes / Q000302:isolation & purification; D011549:Pseudomonas / Q000187:drug effects* / Q000201:enzymology / Q000302:isolation & purification; D013183:Sputum / Q000382:microbiology*; D001618:beta-Lactamases / Q000302:isolation & purification*
D000900:Anti-Bacterial Agents; D007527:Isoenzymes; D001618:beta-Lactamases