Extended-Spectrum Beta-Lactamase Resistance in Clinical Pathogens

Extended-spectrum beta-lactamases (ESBLs) have emerged as a major mechanism of resistance among Gram-negative pathogens, notably Escherichia coli and Klebsiella pneumoniae. These enzymes hydrolyse third-generation cephalosporins and monobactams, undermining key treatments for severe infections. ESBL genes are often carried on conjugative plasmids that co-harbour additional resistance determinants, facilitating rapid dissemination across species and geographic regions. Beyond classic TEM, SHV and CTX-M families, new allelic variants continue to arise through point mutations and gene amplification, sometimes in combination with porin loss or efflux-pump overexpression. The clinical impact is profound: increased therapeutic failure, prolonged hospital stays and greater reliance on carbapenems. Surveillance, precise detection and stewardship remain central to managing this evolving threat, as laboratories and clinicians strive to adapt diagnostics and treatment guidelines to the dynamic landscape of ESBL-mediated resistance.

Research from Nature Portfolio

Recent studies have elucidated both β-lactamase-dependent and ‑independent evolutionary routes to high-level ampicillin resistance. Using large-scale adaptive laboratory evolution, investigators generated Escherichia coli mutants on gradient agar plates and identified mechanisms beyond classic AmpC overproduction. Whole-genome sequencing revealed that, in strains lacking ampC, resistance still emerged through combinations of mutations in efflux pumps, transcriptional regulators and outer-membrane porins. This work underscores the multifactorial nature of β-lactam resistance and highlights latent adaptive pathways that may be activated under selective pressure, signalling the need for comprehensive surveillance of both enzyme variants and auxiliary resistance mechanisms.

Extended-Spectrum Beta-Lactamase Resistance in Clinical Pathogens publication trend

The graph below shows the total number of articles in extended-spectrum beta-lactamase resistance in clinical pathogens across all publications each year (not limited to Nature Index journals).

Technical terms

Extended-spectrum beta-lactamase (ESBL): Enzymes that hydrolyse advanced cephalosporins and monobactams, conferring resistance in Gram-negative bacteria.

AmpC beta-lactamase: A class of β-lactamase that degrades a broad spectrum of β-lactam antibiotics, encoded chromosomally or on plasmids.

Porins: Protein channels in the outer membrane of Gram-negative bacteria that permit diffusion of small molecules, including antibiotics.

Efflux pump: Membrane transport proteins that actively export antibiotics and other toxic compounds out of bacterial cells.

Mobile genetic element: Segments of DNA such as transposons or integrons that facilitate horizontal transfer of resistance genes between bacteria.

References

1. Beta-lactamase dependent and independent evolutionary paths to high-level ampicillin resistance. Nature Communications (2024).
2. Progression of ampC amplification during de novo amoxicillin resistance development in E. coli. mBio (2024).
3. A Guide Towards the Phenotypic Detection of Extended-spectrum β-lactamases Production in Enterobacteriaceae: Alone or in Presence of Other Interfering Enzymes. Journal of Pure and Applied Microbiology (2023).
4. A Review of SHV Extended-Spectrum β-Lactamases: Neglected Yet Ubiquitous. Frontiers in Microbiology (2016).