Rapid decline of bacterial drug-resistance in an antibiotic-free environment through phenotypic reversion

Anett Dunai, Réka Spohn, Zoltán Farkas, Viktória Lázár, Ádám Györkei, Gábor Apjok, Gábor Boross, Balázs Szappanos, Gábor Grézal, Anikó Faragó, L. Bodai, B. Papp, C. Pál

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1 Citation (Scopus)


Antibiotic resistance typically induces a fitness cost that shapes the fate of antibiotic-resistant bacterial populations. However, the cost of resistance can be mitigated by compensatory mutations elsewhere in the genome, and therefore the loss of resistance may proceed too slowly to be of practical importance. We present our study on the efficacy and phenotypic impact of compensatory evolution in Escherichia coli strains carrying multiple resistance mutations. We have demonstrated that drug-resistance frequently declines within 480 generations during exposure to an antibiotic-free environment. The extent of resistance loss was found to be generally antibiotic-specific, driven by mutations that reduce both resistance level and fitness costs of antibiotic-resistance mutations. We conclude that phenotypic reversion to the antibiotic-sensitive state can be mediated by the acquisition of additional mutations, while maintaining the original resistance mutations. Our study indicates that restricting antimicrobial usage could be a useful policy, but for certain antibiotics only.

Original languageEnglish
Publication statusPublished - Aug 16 2019



  • antibiotic resistance
  • compensatory mutations
  • E. coli
  • evolution
  • evolutionary biology

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)

Cite this

Dunai, A., Spohn, R., Farkas, Z., Lázár, V., Györkei, Á., Apjok, G., Boross, G., Szappanos, B., Grézal, G., Faragó, A., Bodai, L., Papp, B., & Pál, C. (2019). Rapid decline of bacterial drug-resistance in an antibiotic-free environment through phenotypic reversion. eLife, 8. https://doi.org/10.7554/eLife.47088