FIG. 2.

Persister levels in longitudinal clonal isolates of P. aeruginosa from a CF patient. (A) The number of mutations at the time a given strain was isolated (47); (B) persister levels (percent survival ± SEM; n = 3) of 35 longitudinal isolates of P. aeruginosa. Stationary-phase cultures were exposed to 100 μg/ml of ofloxacin for 8 h, and surviving cells were determined by colony count. hip mutants are indicated with black bars. (C) Persister progeny from the 96-month hip mutant form the same levels of persisters. The 96-month isolate was grown to the stationary phase and treated with 100× the MIC of ofloxacin for 8 h, and persister levels were determined (96-month isolate persisters). Persisters were regrown to the stationary phase (progeny of 96-month isolate persisters) and then treated with 100× the MIC of ofloxacin for 8 h, after which persister levels were determined were determined by colony count (persisters of progeny) (log [CFU/ml] ± SEM; n = 3).