Open Access Research article

Quantitative analysis of persister fractions suggests different mechanisms of formation among environmental isolates of E. coli

Niels Hofsteenge, Erik van Nimwegen and Olin K Silander*

Author Affiliations

Computational and Systems Biology, Biozentrum, University of Basel, Basel, Switzerland

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BMC Microbiology 2013, 13:25  doi:10.1186/1471-2180-13-25

Published: 4 February 2013

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Additional file 1:

Appendix.

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Additional file 2: Table S1:

Minimum inhibitory antibiotic concentrations for each strain. The MICs ranged between 15-22.5 μg/ml for ampicillin, between 0.008-0.030 μg/ml for ciprofloxacin and 3-7.5 μg/ml for nalidixic acid. This variation in MICs was considerably smaller than the variation in persister fractions exhibited by the selected strains and moreover, the fraction of persisters and their corresponding MICs showed no correlation, suggesting that the variation in MICs does not account for the one observed in the level of persister cells. No resistance to the three used antibiotics was evident for any of the examined.

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Additional file 3: Table S2:

Estimated death rates and switching rates for all strains in the three antibiotics (ampicillin, ciprofloxacin, and nalidixic acid). The parameters are explained in the Additional file 1. Electronic supplementary material.

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Additional file 4:

R code for maximum likelihood fitting. The R code used to perform the fits of the data is provided.

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