FIG 3.

Main phenotypic characteristics of persister cells. (A) Persisters (red bacteria) are present under planktonic and biofilm conditions and account for only a small subset of the whole population (0.001% to 0.1%). (B) Persisters are not resistant mutants. After treatment of a bacterial population with a bactericidal antibiotic, all nonpersister cells die, giving a biphasic survival curve. After a rapid decrease, surviving cell fractions reach a plateau corresponding to persisters (red curve). After antibiotic removal and addition of rich medium, persisters resume growth. The population obtained displays a susceptible phenotype toward the antibiotic (blue curve). If a resistant mutant were present, it would be able to grow in the presence of the antibiotic (dotted line). Panel B was inspired by previous reports (13, 31, 94).