title: GES-18, a new carbapenem-hydrolyzing GES-Type β-lactamase from Pseudomonas aeruginosa that contains Ile80 and Ser170 residues.
abstract: A clinical isolate of Pseudomonas aeruginosa recovered from the lower respiratory tract of an 81-year-old patient hospitalized in Belgium was sent to the national reference center to determine its resistance mechanism. PCR sequencing identified a new GES variant, GES-18, which differs from the carbapenem-hydrolyzing enzyme GES-5 by a single amino acid substitution (Val80Ile, in the numbering according to Ambler) and from GES-1 by two substitutions (Val80Ile and Gly170Ser). Detailed kinetic characterization showed that GES-18 and GES-5 hydrolyze imipenem and cefoxitin with similar kinetic parameters and that GES-18 was less susceptible than GES-1 to classical β-lactamase inhibitors such as clavulanate and tazobactam. The overall structure of GES-18 is similar to the solved structures of GES-1 and GES-2, the Val80Ile and Gly170Ser substitutions causing only subtle local rearrangements. Notably, the hydrolytic water molecule and the Glu166 residue were slightly displaced compared to their counterparts in GES-1. Our kinetic and crystallographic data for GES-18 highlight the pivotal role of the Gly170Ser substitution which distinguishes GES-5 and GES-18 from GES-1.
authors.affiliation: Institute of Molecular Biotechnology, RWTH-Aachen University, c/o Fraunhofer IME, Aachen, Germany. carine.bebrone@molbiotech
authors.forename: Carine
authors.initials: C
authors.lastname: Bebrone
authors.forename: Pierre
authors.initials: P
authors.lastname: Bogaerts
authors.forename: Heinrich
authors.initials: H
authors.lastname: Delbrück
authors.forename: Sandra
authors.initials: S
authors.lastname: Bennink
authors.forename: Michaël B
authors.initials: MB
authors.lastname: Kupper
authors.forename: Roberta
authors.initials: R
authors.lastname: Rezende de Castro
authors.forename: Youri
authors.initials: Y
authors.lastname: Glupczynski
authors.forename: Kurt M
authors.initials: KM
authors.lastname: Hoffmann
mesh_terms: D000369:Aged, 80 and over; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D020134:Catalytic Domain; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D007700:Kinetics; D008297:Male; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011552:Pseudomonas Infections / Q000188:drug therapy* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012141:Respiratory Tract Infections / Q000188:drug therapy* / Q000382:microbiology; D001618:beta-Lactamases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D047090:beta-Lactams / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D011994:Recombinant Proteins; D047090:beta-Lactams; D001618:beta-Lactamases