What's new in antibiotic resistance? Focus on beta-lactamases

Drug Resist Updat. 2006 Jun;9(3):142-56. doi: 10.1016/j.drup.2006.05.005. Epub 2006 Aug 8.


In gram-negative bacteria, beta-lactamases are the most important mechanism of resistance to beta-lactam antibiotics. Currently, the beta-lactamases receiving the most attention are the extended-spectrum beta-lactamases (ESBLs), inhibitor-resistant beta-lactamases and carbapenemases. When found in Escherichia coli and Klebsiella spp., ESBLs confer resistance to extended-spectrum cephalosporins, such as ceftazidime, cefotaxime and cefepime. Hence, ESBLs limit the choice of beta-lactam therapy to carbapenems. A worrisome trend is the increasing number of pathogens found in isolates from patients in the community that possess ESBLs. It is equally distressing that carbapenemases (serine and metallo-beta-lactamases) are being found in many of the same bacteria that harbor ESBLs, for example Klebsiella pneumoniae. Despite many years studying beta-lactamases, important clinical and scientific questions still remain.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Animals
  • Bacteria / drug effects*
  • Bacteria / enzymology*
  • Bacteria / genetics
  • Bacterial Infections / drug therapy
  • Bacterial Infections / microbiology
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Drug Resistance, Bacterial / physiology*
  • Enzyme Inhibitors / pharmacology
  • Humans
  • Microbial Sensitivity Tests
  • Plasmids / genetics
  • beta-Lactamase Inhibitors
  • beta-Lactamases / classification
  • beta-Lactamases / genetics
  • beta-Lactamases / metabolism
  • beta-Lactamases / physiology*
  • beta-Lactams / pharmacology


  • Bacterial Proteins
  • Enzyme Inhibitors
  • beta-Lactamase Inhibitors
  • beta-Lactams
  • AmpC beta-lactamases
  • beta-Lactamases
  • carbapenemase