title: Simultaneous production of two types of beta-lactamase in Escherichia coli and Providencia stuartii.
abstract: The production of beta-lactamase has been studied in two strains isolated from clinical samples: Providencia stuartii MULB 501 and Escherichia coli MULB 130. These strains were selected for their high resistance level to penicillins and cephalosporins. Determination and identification of beta-lactamase activity were achieved by combining several up-to-date methods including (i) neutralization by anti-beta-lactamase sera, (ii) purification by affinity chromatography on cephalosporin C linked Sepharose 4B, (iii) determination of substrate specificity and kinetic values (Km and Vmax) by a computerized microacidimetric method, and (iv) isoelectric focusing. The results clearly demonstrate that in these two strains there is a simultaneous production of different beta-lactamases: the first one is similar to the TEM penicillinase and the second one shares a typical cephalosporinase profile. This double beta-lactamase production is a relatively rare phenomenon.
mesh_terms: D001424:Bacterial Infections / Q000382:microbiology*; D002510:Cephalosporinase / Q000302:isolation & purification; D002511:Cephalosporins / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D010403:Penicillin Resistance; D010405:Penicillinase / Q000302:isolation & purification; D011511:Proteus / Q000201:enzymology*; D011532:Providencia / Q000187:drug effects / Q000201:enzymology*; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: D002511:Cephalosporins; D002510:Cephalosporinase; D010405:Penicillinase; D001618:beta-Lactamases