Integron activity accelerates the evolution of antibiotic resistance

Mobile integrons are widespread genetic platforms that allow bacteria to modulate the expression of antibiotic resistance cassettes by shuffling their position from a common promoter. Antibiotic stress induces the expression of an integrase that excises and integrates cassettes, and this unique reco...

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Bibliographic Details
Published in:eLife 2021-02, Vol.10
Main Authors: Souque, Célia, Escudero, José Antonio, MacLean, R Craig
Format: Article
Language:English
Subjects:
Adaptation
Anti-Bacterial Agents - pharmacology
Antibiotic resistance
Antibiotics
Arrays
Bacteria
Dihydrofolate reductase
Drug resistance
Drug Resistance, Bacterial - genetics
Enzymes
Evolution
Evolution, Molecular
Evolutionary Biology
experimental evolution
Gentamicin
Hypotheses
Integrase
integron
Integrons - genetics
Microbiology and Infectious Disease
P. aeruginosa
Plasmids
Pseudomonas aeruginosa - drug effects
Pseudomonas aeruginosa - genetics
Recombination
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Description
Summary:Mobile integrons are widespread genetic platforms that allow bacteria to modulate the expression of antibiotic resistance cassettes by shuffling their position from a common promoter. Antibiotic stress induces the expression of an integrase that excises and integrates cassettes, and this unique recombination and expression system is thought to allow bacteria to 'evolve on demand' in response to antibiotic pressure. To test this hypothesis, we inserted a custom three-cassette integron into and used experimental evolution to measure the impact of integrase activity on adaptation to gentamicin. Crucially, integrase activity accelerated evolution by increasing the expression of a gentamicin resistance cassette through duplications and by eliminating redundant cassettes. Importantly, we found no evidence of deleterious off-target effects of integrase activity. In summary, integrons accelerate resistance evolution by rapidly generating combinatorial variation in cassette composition while maintaining genomic integrity.
ISSN:2050-084X
2050-084X
DOI:10.7554/eLife.62474