Bench-to-bedside review: The role of beta-lactamases in antibiotic-resistant Gram-negative infections

Crit Care. 2010;14(3):224. doi: 10.1186/cc8892. Epub 2010 Jun 29.

Abstract

Multidrug resistance has been increasing among Gram-negative bacteria and is strongly associated with the production of both chromosomal- and plasmid-encoded beta-lactamases, whose number now exceeds 890. Many of the newer enzymes exhibit broad-spectrum hydrolytic activity against most classes of beta-lactams. The most important plasmid-encoded beta-lactamases include (a) AmpC cephalosporinases produced in high quantities, (b) the expanding families of extended-spectrum beta-lactamases such as the CTX-M enzymes that can hydrolyze the advanced-spectrum cephalosporins and monobactams, and (c) carbapenemases from multiple molecular classes that are responsible for resistance to almost all beta-lactams, including the carbapenems. Important plasmid-encoded carbapenemases include (a) the KPC beta-lactamases originating in Klebsiella pneumoniae isolates and now appearing worldwide in pan-resistant Gram-negative pathogens and (b) metallo-beta-lactamases that are produced in organisms with other deleterious beta-lactamases, causing resistance to all beta-lactams except aztreonam. beta-Lactamase genes encoding these enzymes are often carried on plasmids that bear additional resistance determinants for other antibiotic classes. As a result, some infections caused by Gram-negative pathogens can now be treated with only a limited number, if any, antibiotics. Because multidrug resistance in Gram-negative bacteria is observed in both nosocomial and community isolates, eradication of these resistant strains is becoming more difficult.

Publication types

  • Review

MeSH terms

  • Drug Resistance, Bacterial*
  • Gram-Negative Bacteria / drug effects*
  • Humans
  • beta-Lactamases / drug effects
  • beta-Lactamases / metabolism*

Substances

  • beta-Lactamases