Extended-spectrum beta-lactamases and other enzymes providing resistance to oxyimino-beta-lactams

Infect Dis Clin North Am. 1997 Dec;11(4):875-87. doi: 10.1016/s0891-5520(05)70395-0.


Bacteria have once again demonstrated their remarkably versatility in meeting the introduction of new classes of beta-lactam antibiotics by modifying available plasmid mediated beta-lactamases to expand their spectrum of action and by incorporating chromosomal beta-lactamase genes onto plasmids that permit their spread to new hosts. Such resistance is more common than presently is appreciated because current NCCLS breakpoints for resistance underestimate its prevalence. A number of risk factors for acquisition of ESBL-producing K. pneumoniae have been defined, but most will be no easier to control than those for infection by MRSA or VRE. More clinical and animal model studies are needed to evaluate options for treatment. Most strains remain susceptible to imipenem and other carbapenems, but carbapenem resistance has appeared either by spread of metallo-beta-lactamase or by production of an AmpC enzyme combined with loss of an outer membrane porin channel. Attack on our adversaries' latest biological weapons is likely to require enhanced versatility on our part as well.

Publication types

  • Review

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Anti-Bacterial Agents / therapeutic use*
  • Ceftazidime / chemistry
  • Disease Outbreaks
  • Gram-Negative Bacteria / enzymology*
  • Gram-Negative Bacteria / genetics
  • Gram-Negative Bacteria / metabolism
  • Gram-Negative Bacterial Infections / drug therapy*
  • Gram-Negative Bacterial Infections / enzymology
  • Humans
  • Klebsiella Infections / drug therapy
  • Klebsiella Infections / enzymology
  • Molecular Structure
  • Plasmids / genetics
  • beta-Lactam Resistance / genetics*
  • beta-Lactamases / genetics
  • beta-Lactamases / metabolism*


  • Anti-Bacterial Agents
  • Ceftazidime
  • beta-Lactamases