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. 2014 Mar 28;459(Pt 2):333–344. doi: 10.1042/BJ20140073

Figure 3. Persister cell formation in E. coli MG1655 encoding the hicA toxin cloned into pBAD/His and the hicB antitoxin cloned into pME6032.

Figure 3

Standardized exponential phase cultures were incubated with arabinose or glucose to induce or repress hicA expression respectively, before treating with antibiotic. (a) hicA was induced with 0.2% arabinose for 3 h and then incubated with 100×MIC ciprofloxacin or ceftazidime and CFU tracked over 30 h. (b) hicA was repressed with 0.2% glucose and induced with a range of arabinose concentrations (0.002–0.2%) for 3 h before treatment with 100×MIC ciprofloxacin for 24 h. (c) As described for (b) except treatment was with 100×MIC ceftazidime. In both (b) and (c), persister frequencies were calculated as CFU numbers post-antibiotic treatment divided by CFU numbers pre-antibiotic treatment. The data are shown as the means±S.E.M. for three biological repeats. ***P<0.001, as determined using one-way ANOVA with Tukey's post test. ND, no detectable colonies.