Esbl

Acronym for "extended-spectrum-ß-lactamase", which stands for a specific form of extended resistance to antibiotics in bacteria. Mutations in the range of known ß-lactamases enable pathogens to develop resistance to penicillins, cephalosporins (including third-generation cephalosporins (e.g. ceftriaxone, cefotaxime, ceftazidime) and aztreonam. Furthermore, resistance is observed in gram-negative bacteria from the Enterobacteriaceae group, especially in E.coli and Klebsiella pneumoniae, Enterobacter, Citrobacter and Proteus. See also MRSA.

Mutations in beta-lactamase genes. ESBLs are classified into nine groups based on their diversity:

• TEM
• SHV
• CTX-M
• PER
• VEB
• GES
• TLA
• BES
• OXA.

The most common are OXA, TEM and SHV. Normally, the active site of β-lactamases contains the amino acid serine. The highly active metallo-β-lactamases have a zinc ion in the active site. An example of this are the New Delhi metallo-β-lactamases (NDM).

There are only a few antibiotics available for the treatment of ESBL-forming pathogens, e.g. carbapenem (imipenem or meropenem), tigecycline or colistin. The best clinical data are available for imipenem and meropenem.

Notice! As a preventive measure, protective gowns should be worn when handling ESBL patients and consistent hand disinfection should be carried out. If ESBL occurs, it is advisable to take hygiene measures similar to those for MRSA.

1. Huggett S et al (2018) Antibiotics Primer 2018/2019 Asclepius, Medical Scientific Publishing Company. S.51-52