title: Incidence of strains producing plasmid determined beta-lactamases among carbenicillin resistant Pseudomonas aeruginosa.
abstract: A total of 1056 strains of Pseudomonas aeruginosa isolated from human clinical specimens from patients was collected from eight laboratories in order to study the frequency of plasmid-determined beta-lactamase producers and the different enzymes represented. The strains from each laboratory comprised consecutive, non-repeated, clinical isolates. In the 166 strains selected because they were carbenicillin resistant, the isoelectric points of the beta-lactamases were studied by means of analytical isoelectric focusing and the different types of plasmid-determined beta-lactamases identified. Seventy-five of the strains (45.18%) were plasmid-mediated beta-lactamase producers; the frequency varied among laboratories from 0% to 100%. Overall the most frequently identified beta-lactamase type was PSE-1 (49.34%) followed by TEM-1 (37.34%). The remaining carbenicillin-resistant strains did not produce plasmid-determined beta-lactamases.
mesh_terms: D002228:Carbenicillin / Q000494:pharmacology*; D007525:Isoelectric Focusing; D008826:Microbial Sensitivity Tests; D010403:Penicillin Resistance; D010957:Plasmids; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000201:enzymology*; D001618:beta-Lactamases / Q000096:biosynthesis / Q000378:metabolism*
chemical_list: D001618:beta-Lactamases; D002228:Carbenicillin