Detection of plasmid-mediated class C beta-lactamases

Int J Infect Dis. 2007 May;11(3):191-7. doi: 10.1016/j.ijid.2006.07.008. Epub 2007 Mar 6.


Plasmid-mediated class C beta-lactamases are reported from Enterobacteriaceae with increasing frequency. They likely originate from chromosomal AmpC of certain Gram-negative bacterial species and subsequently are mobilized onto transmissible plasmids. There are reports of unfavorable clinical outcomes in patients infected with these organisms and treated with broad-spectrum cephalosporins. However, unlike class A extended-spectrum beta-lactamases (ESBLs), no screening and confirmatory tests have been uniformly established for strains that produce class C beta-lactamases. Reduced susceptibility to cefoxitin is a sensitive but not specific indicator of class C beta-lactamase production. Simple confirmatory tests including tests using boronic acid compounds as specific class C beta-lactamase inhibitors have recently been developed. Their utilization will enable clinical microbiology laboratories to report those strains producing plasmid-mediated class C beta-lactamases as being resistant to all broad-spectrum cephalosporins, thus allowing physicians to prescribe appropriate antimicrobial therapy.

Publication types

  • Review

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Cephalosporins / pharmacology*
  • Enterobacteriaceae / drug effects
  • Enterobacteriaceae / enzymology*
  • Enzyme Inhibitors / pharmacology*
  • Enzyme-Linked Immunosorbent Assay
  • Humans
  • Microbial Sensitivity Tests*
  • Plasmids
  • Polymerase Chain Reaction
  • beta-Lactamase Inhibitors
  • beta-Lactamases / analysis*
  • beta-Lactamases / genetics


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