FIG. 1.

Growth and adaptation of C. difficile to nisin. Cells were grown in BHIS medium with or without nisin as indicated (μg/ml). (A) C. difficile growth is inhibited by increasing concentrations of nisin. (B) C. difficile cells preconditioned in nisin at 30 μg/ml are able to grow at normal rates when resuspended in medium without nisin (30-0) or with nisin at 30 μg/ml (30-30). (C) Cells preconditioned in nisin maintain the ability to grow in nisin at the same concentration (30-30-30), but cells preconditioned in nisin (30) and then grown without nisin (30-0) lose the ability to grow in nisin without significant lag (30-0-30).