What does ESBL (Extended-Spectrum Beta-Lactamase) mean?

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From the Guidelines

ESBL (Extended-Spectrum Beta-Lactamase) refers to enzymes produced by certain bacteria that can break down and inactivate many commonly used antibiotics, particularly beta-lactam antibiotics like penicillins and cephalosporins. These enzymes are produced by gram-negative bacteria, most commonly Escherichia coli and Klebsiella species, making infections caused by these organisms difficult to treat with standard antibiotics. ESBL-producing bacteria are resistant to most penicillins, cephalosporins (except cephamycins like cefoxitin), and aztreonam. When treating ESBL infections, carbapenems (such as meropenem, imipenem, or ertapenem) are typically the antibiotics of choice, usually given intravenously for serious infections. In some cases, other options like piperacillin-tazobactam, ceftazidime-avibactam, or fosfomycin may be considered based on susceptibility testing 1. ESBL-producing bacteria are considered multidrug-resistant organisms and are associated with increased mortality, longer hospital stays, and higher healthcare costs. The spread of these resistant bacteria is a growing public health concern, highlighting the importance of appropriate antibiotic use, infection control measures, and proper hand hygiene in healthcare settings. Key points to consider in the management of ESBL-producing bacteria include:

  • The use of rapid testing strategies to identify specific resistance mechanisms and guide antibiotic therapy 1
  • The importance of antibiotic stewardship to prevent the spread of resistance
  • The need for infection control measures to prevent the transmission of ESBL-producing bacteria in healthcare settings. It is crucial to note that the management of ESBL-producing bacteria requires a comprehensive approach that includes appropriate antibiotic use, infection control measures, and proper hand hygiene in healthcare settings. In terms of treatment, carbapenems are typically the antibiotics of choice for serious ESBL infections. However, the choice of antibiotic should be guided by susceptibility testing and the specific resistance mechanism involved 1. Overall, the management of ESBL-producing bacteria requires a careful and nuanced approach that takes into account the latest evidence and guidelines.

From the FDA Drug Label

As with other extended-spectrum beta-lactam antibacterial drugs, resistance can develop during therapy, leading to clinical failure in some cases. The term ESBL stands for Extended-Spectrum Beta-Lactamase, which refers to a type of enzyme produced by certain bacteria that makes them resistant to beta-lactam antibiotics, including extended-spectrum cephalosporins like ceftazidime 2.

From the Research

Definition of ESBL

  • ESBL stands for Extended-Spectrum Beta-Lactamase, which refers to a group of enzymes that hydrolyze antibiotics, including those containing new cephalosporins 3, 4, 5, 6, 7.
  • These enzymes are found in a significant percentage of Escherichia coli and Klebsiella pneumoniae strains, and are often plasmid-encoded, allowing for easy transfer between bacteria 4, 5, 7.

Characteristics of ESBLs

  • ESBLs are capable of hydrolyzing third-generation cephalosporins and aztreonam, but are inhibited by clavulanic acid 4, 5, 6.
  • They are derived from genes for TEM-1, TEM-2, or SHV-1 by mutations that alter the amino acid configuration around the active site of these beta-lactamases 4, 6.
  • ESBL-producing organisms often exhibit co-resistance to many other classes of antibiotics, resulting in limited therapeutic options 3, 4, 5, 7.

Clinical Significance of ESBLs

  • The presence of ESBLs carries tremendous clinical significance, as they can lead to treatment failures and increased morbidity and mortality 4, 5, 7.
  • Carbapenems are often the treatment of choice for serious infections due to ESBL-producing organisms, but carbapenem-resistant isolates have been reported 4, 5, 7.
  • Efficient infection-control practices and intervention strategies, such as antibiotic rotation, are necessary to reduce the selection and spread of these resistant pathogens 5.

Detection and Diagnosis of ESBLs

  • The detection of ESBLs can be complex and sometimes misleading, and requires specialized laboratory tests 4, 5, 7.
  • Organizations such as the Clinical and Laboratory Standards Institute provide guidelines for the detection of ESBLs in certain bacterial species 4, 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Extended-spectrum beta-lactamases: a clinical update.

Clinical microbiology reviews, 2005

Research

Extended-spectrum β-lactamases in Gram Negative Bacteria.

Journal of global infectious diseases, 2010

Research

Defining an extended-spectrum beta-lactamase.

Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases, 2008

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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