Trends in Beta-Lactam Resistance Among Enterobacteriaceae

Clin Infect Dis. 1998 Aug;27 Suppl 1:S100-6. doi: 10.1086/514905.


beta-Lactam resistance among Enterobacteriaceae is related primarily to the emergence of novel beta-lactamases. The class A extended-spectrum beta-lactamases hydrolyze extended-spectrum beta-lactams and are inhibited by clavulanic acid. These beta-lactamases are divided in two groups: TEM and SHV derivatives and non-TEM and non-SHV extended-spectrum beta-lactamases (CTX-M1, CTX-M2, MEN-1, PER-1, PER-2, TOHO-1, and VEB-1). The plasmid-mediated cephalosporinases (MIR-1, FOX-1, MOX-1, BIL-1, CMY-1, CMY-2, and LAT-1) hydrolyze extended-spectrum cephalosporins and cephamycins and are not inhibited by clavulanic acid. They have been reported in Europe and in the United States. The 15 inhibitor-resistant penicillinases are TEM derivatives (except for SHV-10) and plasmid mediated, and they are mainly from Escherichia coli isolates. The carbapenemases noted among Enterobacteriaceae are either the chromosomally located penicillinases (Sme-1, NmcA, IMI-1) found in rare Enterobacter cloacae or Serratia marcescens isolates or the plasmid-mediated metalloenzyme IMP-1 that is widespread in Japan. The incidence of resistance among Enterobacteriaceae related to the other more common beta-lactam-resistance mechanisms has continued to rise worldwide.

Publication types

  • Review

MeSH terms

  • Animals
  • Carbapenems / pharmacology
  • Cephalosporinase / pharmacology
  • Enterobacteriaceae / drug effects*
  • Enterobacteriaceae / enzymology
  • Humans
  • Plasmids
  • beta-Lactam Resistance* / genetics
  • beta-Lactam Resistance* / physiology
  • beta-Lactamase Inhibitors
  • beta-Lactamases / genetics
  • beta-Lactamases / metabolism


  • Carbapenems
  • beta-Lactamase Inhibitors
  • Cephalosporinase
  • beta-Lactamases