Enhanced Fitness of E. coli Due to qnrA3 Gene
Author Information
Author(s): Michon Adrien, Allou Nicolas, Chau Françoise, Podglajen Isabelle, Fantin Bruno, Cambau Emmanuelle
Primary Institution: EA 3964, University Paris Diderot, Paris, France
Hypothesis
Qnr proteins may provide a selective advantage to bacteria beyond antibiotic resistance.
Conclusion
Acquisition of the qnrA3 gene enhances bacterial fitness in E. coli, but this fitness is reduced when the gene is carried on multidrug-resistant plasmids.
Supporting Evidence
- E. coli CFT073 transformed with pBRAM(PBR322-qnrA3) had significantly higher maximal OD than E. coli CFT073 transformed with pBR322.
- In vivo competitions were more often won by the qnrA3 carrying strain (24 victories vs. 9 losses among 42 competitions).
- Fitness was reduced when qnrA3 was introduced on multidrug-resistant plasmids.
Takeaway
Bacteria can become stronger without antibiotics by gaining certain genes, but sometimes those genes can make them weaker if they come with other resistance traits.
Methodology
The study involved in vitro growth analysis and in vivo competitions using mouse models to assess the fitness of E. coli strains with and without the qnrA3 gene.
Limitations
Plasmid instability was significant for some plasmid constructions, affecting the results.
Statistical Information
P-Value
0.001
Statistical Significance
p<0.0001
Digital Object Identifier (DOI)
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