FIG. 2.

Hemolytic variant generation in cultures of S. aureus FRI1169. (A) Isolates from drip reactors plated onto sheep blood agar. (B) Distribution of hemolytic (▪), hyperhemolytic (▒), and nonhemolytic (□) isolates in overnight culture used to inoculate drip reactors, 2-week-old drip reactor biofilms, and 2-week-old chemostat (planktonic) cultures. Values represent averages and standard deviations of three independent cultures. Changes in the hemolytic and nonhemolytic (but not the hyperhemolytic) populations between the biofilm and chemostat cultures are significant (P < 0.001, Student t test). (C) Hemolytic (⧫), hyperhemolytic (•), and nonhemolytic (○) isolates from drip reactor biofilms sampled at 0, 4, 11, and 14 days after inoculation.