TEM-121, a novel complex mutant of TEM-type beta-lactamase from Enterobacter aerogenes

Antimicrob Agents Chemother. 2004 Dec;48(12):4528-31. doi: 10.1128/AAC.48.12.4528-4531.2004.

Abstract

Enterobacter aerogenes clinical isolate LOR was resistant to penicillins and ceftazidime but susceptible to cefuroxime, cephalothin, cefoxitin, cefotaxime, ceftriaxone, and cefepime. PCR and cloning experiments from this strain identified a novel TEM-type beta-lactamase (TEM-121) differing by five amino acid substitutions from beta-lactamase TEM-2 (Glu104Lys, Arg164Ser, Ala237Thr, Glu240Lys, and Arg244Ser) and by only one amino acid change from the extended-spectrum beta-lactamase (ESBL) TEM-24 (Arg244Ser), with the last substitution also being identified in the inhibitor-resistant beta-lactamase IRT-2. Kinetic parameters indicated that TEM-121 hydrolyzed ceftazidime and aztreonam (like TEM-24) and was inhibited weakly by clavulanic acid and strongly by tazobactam. Thus, TEM-121 is a novel complex mutant TEM beta-lactamase (CMT-4) combining the kinetic properties of an ESBL and an inhibitor-resistant TEM enzyme.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ceftazidime / pharmacology*
  • Cephalosporin Resistance
  • Cephalosporins / pharmacology*
  • Clavulanic Acid / pharmacology
  • Cloning, Molecular
  • DNA, Bacterial / biosynthesis
  • DNA, Bacterial / genetics
  • Enterobacter aerogenes / enzymology*
  • Enterobacter aerogenes / genetics*
  • Enzyme Inhibitors / pharmacology
  • Isoelectric Focusing
  • Kinetics
  • Microbial Sensitivity Tests
  • Molecular Sequence Data
  • Mutation
  • Plasmids / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Transformation, Bacterial
  • beta-Lactam Resistance
  • beta-Lactamases / genetics*
  • beta-Lactamases / metabolism*

Substances

  • Cephalosporins
  • DNA, Bacterial
  • Enzyme Inhibitors
  • Clavulanic Acid
  • Ceftazidime
  • beta-Lactamases
  • beta-lactamase TEM-121, Enterobacter aerogenes