title: Extended-spectrum beta-lactamase in Proteus mirabilis.
abstract: Over a period of one month, five isolates of Proteus mirabilis resistant to extended-spectrum cephalosporins colonized or infected five patients of the same intensive care unit. The antibiotic resistance phenotype and the metabolic profiles of the five strains were identical. All five produced a plasmid-mediated extended-spectrum beta-lactamase closely related to TEM-3/CTX-1 according to its pI (6.3), to its substrate profile and to the hybridization of the corresponding gene with blaTEM-3 specific oligonucleotide probes. Ability to produce this enzyme transferred by conjugation to Escherichia coli along with aminoglycoside and sulphonamide resistance. These resistance markers were encoded by a plasmid, (pAP1) which was identical in all five isolates but which was different from the TEM-3 beta-lactamase plasmids found in other Enterobacteriaceae. Plasmid pAP1 differed by its smaller size (47 kb), its EcoRI restriction pattern, its resistance co-markers (AAC(6') and sulphonamide only) and its much lower transfer frequency (2 x 10(-8)). Furthermore this plasmid did not belong to any known Enterobacteriaceae incompatibility group.
authors.affiliation: Laboratoire de Microbiologie, Hôpital Ambroise Paré, Faculté de Médicine, Paris-Ouest, Boulogne, France.
authors.forename: S
authors.initials: S
authors.lastname: Mariotte
authors.forename: P
authors.initials: P
authors.lastname: Nordmann
authors.forename: M H
authors.initials: MH
authors.lastname: Nicolas
mesh_terms: D002510:Cephalosporinase / Q000378:metabolism*; D002511:Cephalosporins / Q000494:pharmacology; D003428:Cross Infection / Q000382:microbiology; D004269:DNA, Bacterial / Q000302:isolation & purification; D004352:Drug Resistance, Microbial; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D005819:Genetic Markers; D006801:Humans; D007362:Intensive Care Units; D008826:Microbial Sensitivity Tests; D009693:Nucleic Acid Hybridization; D000073718:Pancreatitis-Associated Proteins; D010957:Plasmids; D011512:Proteus Infections / Q000382:microbiology; D011513:Proteus mirabilis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics
chemical_list: D002511:Cephalosporins; D004269:DNA, Bacterial; D005819:Genetic Markers; D000073718:Pancreatitis-Associated Proteins; C000612141:REG3A protein, human; D002510:Cephalosporinase