Open Access Highly Accessed Open Badges Research article

The evolution of antibiotic susceptibility and resistance during the formation of Escherichia coli biofilms in the absence of antibiotics

Jabus G Tyerman126, José M Ponciano3, Paul Joyce245, Larry J Forney12 and Luke J Harmon12*

Author affiliations

1 Department of Biological Sciences, University of Idaho, Campus Box 3051, Moscow, ID, 83843, USA

2 Initiative for Bioinformatics and Evolutionary Studies (IBEST), University of Idaho, Moscow, ID, 83844, USA

3 Department of Biology, University of Florida, Gainesville, FL, USA

4 Departments of Mathematics, University of Idaho, Moscow, Moscow, ID, 83844, USA

5 Departments of Statistics, University of Idaho, Moscow, ID, 83844, USA

6 Current address: Genomatica, Inc., 10520 Wateridge Circle, San Diego, CA, 92121, USA

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Citation and License

BMC Evolutionary Biology 2013, 13:22  doi:10.1186/1471-2148-13-22

Published: 28 January 2013



Explanations for bacterial biofilm persistence during antibiotic treatment typically depend on non-genetic mechanisms, and rarely consider the contribution of evolutionary processes.


Using Escherichia coli biofilms, we demonstrate that heritable variation for broad-spectrum antibiotic resistance can arise and accumulate rapidly during biofilm development, even in the absence of antibiotic selection.


Our results demonstrate the rapid de novo evolution of heritable variation in antibiotic sensitivity and resistance during E. coli biofilm development. We suggest that evolutionary processes, whether genetic drift or natural selection, should be considered as a factor to explain the elevated tolerance to antibiotics typically observed in bacterial biofilms. This could be an under-appreciated mechanism that accounts why biofilm populations are, in general, highly resistant to antibiotic treatment.

Evolution; Antibiotic resistance; Bacterial biofilms; Mutations; Diversity