[Resistance caused by hyperproduction of chromosomal beta-lactamase in Pseudomonas aeruginosa].
From 120 Pseudomonas aeruginosa strains selected for their slight susceptibility to ceftazidime (MIC greater than or equal to 16 micrograms/ml) we studied the characteristics of beta-lactamases and their susceptibility to aminoglycoside and to beta-lactam antibiotics. The quantitative spectrum, chromosomic beta-lactamase hyperproduction and the isoelectric point of beta-lactamases were also studied as well as the MIC in solid medium, inoculum 5 x 10(4) cfu. About 14.7% of strains moderately susceptible to ceftazidime and 88.4% of those resistant, were hyperproducers of chromosomic beta-lactamases. All the strains were resistant to ureidopenicillins, cefotaxime and moxalactam, 55.8% to monobactams and 35% were also resistant to cefsulodine; all of them were susceptible to imipenem. In bacteria isolated from twelve patients a loss of susceptibility could be observed against ceftazidime and other beta-lactams. There was also an increase in chromosomic beta-lactamase production during the treatment with antibiotics.
Tirado
M
M
Hermida
M
M
Reig
R
R
Esteva
C
C
Vidal
R
R
Roy
C
C
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000302:isolation & purification; D002876:Chromosomes, Bacterial; D004352:Drug Resistance, Microbial; D006801:Humans; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000302:isolation & purification; D047090:beta-Lactams
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D047090:beta-Lactams; D001618:beta-Lactamases
Resistencia por hiperproducción de betalactamasa cromosómica en Pseudomonas aeruginosa.