Extended-spectrum beta-lactamases in North America, 1987-2006

Clin Microbiol Infect. 2008 Jan;14 Suppl 1:134-43. doi: 10.1111/j.1469-0691.2007.01848.x.


Extended-spectrum beta-lactamases (ESBLs) derived from the TEM-1 beta-lactamase were first identified in the USA in outbreak strains of Klebsiella pneumoniae in the middle to late 1980s, together with the SHV-5 ESBL. The TEM-10, TEM-12 and TEM-26 enzymes have remained in US hospitals, but have been joined by other ESBLs that are variants of the SHV-1 broad-spectrum beta-lactamase. In the most recent surveys from hospitals in the eastern part of the USA, the most prominent ESBLs have been the SHV-7 and SHV-12 enzymes. In Canada, a wider variety of ESBLs has been identified, with multiple members of the TEM, SHV and CTX-M classes being represented in surveillance isolates. SHV-type and CTX-M ESBLs have appeared in many Canadian isolates, with an outbreak of CTX-M-14-related enzymes from Calgary, but limited TEM-derived ESBLs. Surprisingly, few CTX-M ESBLs have yet been reported in the USA, in contrast to the rest of the world, where the CTX-M enzymes have become a predominant ESBL family.

Publication types

  • Review

MeSH terms

  • Amino Acid Substitution
  • Canada / epidemiology
  • Drug Resistance, Multiple, Bacterial / genetics
  • Enterobacteriaceae / classification
  • Enterobacteriaceae / drug effects*
  • Enterobacteriaceae / enzymology*
  • Enterobacteriaceae / genetics
  • Enterobacteriaceae Infections / epidemiology*
  • Enterobacteriaceae Infections / microbiology
  • Humans
  • North America / epidemiology
  • Population Surveillance / methods
  • United States / epidemiology
  • beta-Lactamases / biosynthesis*
  • beta-Lactamases / classification
  • beta-Lactamases / genetics


  • beta-Lactamases