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. Author manuscript; available in PMC: 2014 Jan 1.
Published in final edited form as: Nat Genet. 2013 Jun 9;45(7):784–790. doi: 10.1038/ng.2656

Figure 3. The cumulative distribution of drug resistant mutants from both lineages indicates that mutations do not occur after exposure to antibiotic.

Figure 3

(a) Curve fitting analysis was performed to determine if the cumulative distribution of the fluctuation analysis data from Lineage 4 strain CDC-1551 plated on rifampicin, 0.5μg/mL better fit a one-parameter Luria-Delbrück (LD) model, a one parameter Poisson model (Poiss), or a two-parameter Luria-Delbrück and Poisson mixture model (TP). The number of mutants per culture is displayed on the x-axis, and the probability of observing x or fewer mutants per culture is shown on the y-axis. (b) Fitting as in (a) for Lineage 2 strain HN878 plated on rifampicin, 0.5μg/mL. (c) Fitting as in (a) for Lineage 4 strain CDC-1551 plated on rifampicin, 2μg/mL. (d) Fitting as in (a) for Lineage 2 strain HN878 plated on rifampicin, 2μg/mL. (e) Fitting as in (a) data for Lineage 4 strain CDC-1551 plated on rifampicin, 5μg/mL. (f) Fitting as in (a) data for Lineage 2 strain HN878 plated on rifampicin, 5μg/mL. (g) To determine which model best fit each data set, we determined the Akaike Information Criterion, corrected for small sample size (AICC). A smaller AICC represents a better fit, given a penalty for more parameters in a model. If the AICC(LD) is smaller than the AICC(TP), then the resulting value will be negative, reflecting a better fit for the LD model (see Supplementary Table 2).