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Updated: Aug 11, 2026

The Use of a β-lactamase-based Conductimetric Biosensor Assay to Detect Biomolecular Interactions
08:06

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Published on: February 1, 2018

CTX-M-type beta-lactamases: an emerging group of extended-spectrum enzymes

L S Tzouvelekis1, E Tzelepi, P T Tassios

  • 1Department of Microbiology, Medical School, National University of Athens, M. Asias 75, Athens, Greece.

International Journal of Antimicrobial Agents
|March 18, 2000
PubMed

Insights

CTX-M-type beta-lactamases are a new class of enzymes found in enterobacteria that hydrolyze broad-spectrum antibiotics. These enzymes, encoded by plasmids, are prevalent in Latin America and parts of Europe.

Area of Science:

  • Microbiology
  • Biochemistry
  • Molecular Biology

Background:

  • CTX-M-type beta-lactamases represent a novel group of class A beta-lactamases.
  • These enzymes possess extended-spectrum hydrolytic properties.

Purpose of the Study:

  • To discuss the structure, properties, and epidemiology of CTX-M enzymes.
  • To highlight their significance in antibiotic resistance.

Main Methods:

  • Comparative sequence analysis.
  • Enzyme activity assays.
  • Epidemiological surveillance data analysis.

Main Results:

  • CTX-M enzymes efficiently hydrolyze broad-spectrum oximino-beta-lactams (e.g., cefotaxime, ceftriaxone, aztreonam).
  • They are encoded by transferable plasmids and found in key enterobacteria (e.g., Salmonella typhimurium, Escherichia coli, Klebsiella pneumoniae).
  • CTX-M enzymes show similarity to Klebsiella oxytoca chromosomal beta-lactamases and are inhibited by tazobactam and clavulanate.

Conclusions:

  • CTX-M-producing enterobacteria are endemic in Latin America and parts of North Eastern Europe.
  • Understanding CTX-M enzymes is crucial for combating antibiotic resistance.

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