Antibiotic Resistance Mechanisms in Gram-Negative Bacteria

Gram-negative bacteria possess a formidable repertoire of mechanisms to withstand antibiotic challenge, posing a global threat to public health. Central to this resistance is the production of β-lactamases, enzymes that hydrolyse β-lactam antibiotics and range from narrow-spectrum penicillinases to extended-spectrum and carbapenemases. In parallel, alterations in outer membrane porins reduce drug influx, while overexpression of efflux pumps actively expels a broad variety of antimicrobials. Mobile genetic elements, including plasmids, transposons and integrons, facilitate the rapid dissemination of resistance determinants across species and environmental reservoirs. Peptidoglycan recycling pathways modulate inducible chromosomal cephalosporinases, linking cell envelope homeostasis to resistance. Collateral sensitivities arising from specific resistance adaptations offer new therapeutic angles, whereas comprehensive surveillance of minimal inhibitory concentration (MIC) data reveals complex temporal and geographic trends. Together, these interwoven mechanisms not only undermine existing treatments but also drive the evolution of multidrug-resistant lineages that challenge infection control and clinical management worldwide.

Research from Nature Portfolio

Recent work has uncovered collateral sensitivity networks induced by acquisition of mobile β-lactamase plasmids. Studies demonstrate that expression of prevalent β-lactamase genes, such as blaOXA-48, simultaneously engenders hypersusceptibility to agents like colistin and azithromycin, suggesting exploitable vulnerabilities in Enterobacterales. In addition, analyses of vast MIC datasets have revealed non-stationary resistance dynamics within clinical populations, identifying subpopulations undergoing divergent shifts in susceptibility and pinpointing pathogens at imminent risk of clinical resistance. Finally, targeted investigations into chromosomal AmpC regulation in Enterobacter cloacae have shown that peptidoglycan recycling alterations and ampD inactivation yield resistance without detectable fitness or virulence cost, challenging prior paradigms derived from other species and refining our understanding of intrinsic cephalosporinase control.

Antibiotic Resistance Mechanisms in Gram-Negative Bacteria publication trend

The graph below shows the total number of articles in antibiotic resistance mechanisms in gram-negative bacteria across all publications each year (not limited to Nature Index journals).

Technical terms

β-lactamase: Enzyme that hydrolyses the β-lactam ring of penicillins and cephalosporins, neutralising antibiotic activity.

Efflux pump: Membrane protein complex that actively exports antibiotics out of the bacterial cell, reducing intracellular drug concentration.

Porin: Channel in the outer membrane that permits passive diffusion of small molecules, including some antibiotics.

Peptidoglycan recycling: Cellular process reclaiming cell-wall fragments for reuse and regulating inducible chromosomal β-lactamase expression.

Mobile genetic element: DNA segment (plasmid, transposon or integron) capable of horizontal transfer between bacteria, carrying resistance genes.

Extended-spectrum β-lactamase (ESBL): β-lactamase variant that hydrolyses a broad range of cephalosporins and monobactams.

Carbapenemase: β-lactamase capable of hydrolysing carbapenems, often encoded on highly transmissible plasmids.

Horizontal gene transfer: Movement of genetic material between organisms, facilitating rapid dissemination of resistance determinants.

References

1. β-lactamase expression induces collateral sensitivity in Escherichia coli. Nature Communications (2024).
2. Seeking patterns of antibiotic resistance in ATLAS, an open, raw MIC database with patient metadata. Nature Communications (2022).
3. Filling knowledge gaps related to AmpC-dependent β-lactam resistance in Enterobacter cloacae. Scientific Reports (2024).
4. Origin, evolution, and success of pbla, the gonococcal beta-lactamase plasmid, and implications for public health. PLOS Pathogens (2025).
5. Role of peptidoglycan recycling enzymes AmpD and AnmK in Acinetobacter baumannii virulence features. Frontiers in Cellular and Infection Microbiology (2023).
6. A Multispecies Cluster of GES-5 Carbapenemase–Producing Enterobacterales Linked by a Geographically Disseminated Plasmid. Clinical Infectious Diseases (2019).