title: Genetic and Biochemical Characterization of FRI-1, a Carbapenem-Hydrolyzing Class A β-Lactamase from Enterobacter cloacae.
abstract: An Enterobacter cloacae isolate was recovered from a rectal swab from a patient hospitalized in France with previous travel to Switzerland. It was resistant to penicillins, narrow- and broad-spectrum cephalosporins, aztreonam, and carbapenems but remained susceptible to expanded-spectrum cephalosporins. Whereas PCR-based identification of the most common carbapenemase genes failed, the biochemical Carba NP test II identified an Ambler class A carbapenemase. Cloning experiments followed by sequencing identified a gene encoding a totally novel class A carbapenemase, FRI-1, sharing 51 to 55% amino acid sequence identity with the closest carbapenemase sequences. However, it shared conserved residues as a source of carbapenemase activity. Purified β-lactamase FRI-1 hydrolyzed penicillins, aztreonam, and carbapenems but spared expanded-spectrum cephalosporins. The 50% inhibitory concentrations (IC50s) of clavulanic acid and tazobactam were 10-fold higher than those found for Klebsiella pneumoniae carbapenemase (KPC), IMI, and SME, leading to lower sensitivity of FRI-1 activity to β-lactamase inhibitors. The blaFRI-1 gene was located on a ca. 110-kb untypeable, transferable, and non-self-conjugative plasmid. A putative LysR family regulator-encoding gene at the 5' end of the β-lactamase gene was identified, leading to inducible expression of the blaFRI-1 gene.
authors.affiliation: Associated National Reference Center for Antibiotic Resistance, Le Kremlin-Bicêtre, France Faculty of Medicine, South Paris University, Le Kremlin-Bicêtre, France Bacteriology-Hygiene Unit, Hospital Bicêtre, Assistance Publique/Hôpitaux de Paris, and INSERM U914, Le Kremlin-Bicêtre, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Dortet
authors.affiliation: Associated National Reference Center for Antibiotic Resistance, Le Kremlin-Bicêtre, France Faculty of Medicine, South Paris University, Le Kremlin-Bicêtre, France Bacteriology-Hygiene Unit, Hospital Bicêtre, Assistance Publique/Hôpitaux de Paris, and INSERM U914, Le Kremlin-Bicêtre, France Emerging Antibiotic Resistance Unit, Medical and Molecular Microbiology, Department of Medicine, University of Fribourg, Fribourg, Switzerland.
authors.forename: Laurent
authors.initials: L
authors.lastname: Poirel
authors.affiliation: Faculty of Medicine, South Paris University, Le Kremlin-Bicêtre, France.
authors.forename: Samia
authors.initials: S
authors.lastname: Abbas
authors.affiliation: Faculty of Medicine, South Paris University, Le Kremlin-Bicêtre, France.
authors.forename: Saoussen
authors.initials: S
authors.lastname: Oueslati
authors.affiliation: Associated National Reference Center for Antibiotic Resistance, Le Kremlin-Bicêtre, France Faculty of Medicine, South Paris University, Le Kremlin-Bicêtre, France Bacteriology-Hygiene Unit, Hospital Bicêtre, Assistance Publique/Hôpitaux de Paris, and INSERM U914, Le Kremlin-Bicêtre, France Emerging Antibiotic Resistance Unit, Medical and Molecular Microbiology, Department of Medicine, University of Fribourg, Fribourg, Switzerland HFR-Hôpital Cantonal, Fribourg, Switzerland patrice.nordmann@unifr.ch.
authors.forename: Patrice
authors.initials: P
authors.lastname: Nordmann
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D015780:Carbapenems / Q000494:pharmacology; D019818:Clavulanic Acid / Q000494:pharmacology; D003001:Cloning, Molecular; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects / Q000235:genetics*; D016972:Enterobacter cloacae / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D020128:Inhibitory Concentration 50; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010397:Penicillanic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D010957:Plasmids; D017386:Sequence Homology, Amino Acid; D000078142:Tazobactam; D065093:beta-Lactamase Inhibitors / Q000494:pharmacology; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D065093:beta-Lactamase Inhibitors; D019818:Clavulanic Acid; D010397:Penicillanic Acid; D001618:beta-Lactamases; C063912:carbapenemase; D000078142:Tazobactam