Inhibitor-resistant TEM beta-lactamases: phenotypic, genetic and biochemical characteristics

J Antimicrob Chemother. 1999 Apr;43(4):447-58. doi: 10.1093/jac/43.4.447.


Beta-lactamases represent the main mechanism of bacterial resistance to beta-lactam antibiotics. The recent emergence of bacterial strains producing inhibitor-resistant TEM (IRT) enzymes could be related to the frequent use of beta-lactamase inhibitors such as clavulanic acid, sulbactam and tazobactam in hospitals and in general practice. The IRT beta-lactamases differ from the parental enzymes TEM-1 or TEM-2 by one, two or three amino acid substitutions at different locations. This paper reviews the phenotypic, genetic and biochemical characteristics of IRT beta-lactamases in an attempt to shed light on the pressures that have contributed to their emergence.

Publication types

  • Review

MeSH terms

  • Anti-Bacterial Agents / metabolism
  • Anti-Bacterial Agents / pharmacology
  • Enzyme Inhibitors / metabolism
  • Enzyme Inhibitors / pharmacology*
  • Escherichia coli / drug effects
  • Escherichia coli / enzymology
  • beta-Lactam Resistance
  • beta-Lactamase Inhibitors
  • beta-Lactamases* / chemistry
  • beta-Lactamases* / genetics
  • beta-Lactamases* / metabolism
  • beta-Lactams


  • Anti-Bacterial Agents
  • Enzyme Inhibitors
  • beta-Lactamase Inhibitors
  • beta-Lactams
  • beta-Lactamases