FIG 8 .

E. coli CFT073 gdhA persistence. Cultures were grown overnight in 0.4% glucose M9 minimal medium, and persister cell assays were performed as described in Materials and Methods. ♦, E. coli CFT073; ■, E. coli CFT073 plus ampicillin; ▲, E. coli CFT073 gdhA; ●, E. coli CFT073 gdhA plus ampicillin. Bars representing standard errors of the means of counts from 3 independent experiments are presented for each time point. At 24 h, the approximately 2,000-fold difference between E. coli CFT073 persisters and E. coli CFT073 gdhA persisters in the presence of ampicillin is statistically significant (P < 0.001).