Fig. 4.

Growth and toxin production of wild-type CD274 and the CD274/φCD38-2 lysogen. (A) Growth of the wild type (white circles) and the lysogen (black circles) in TY broth was monitored by measuring the optical density at 600 nm over 24 h. (B) The relative amounts of TcdA and TcdB toxins were determined by a toxin A/B ELISA. Data represent the means ± standard deviations from three independent biological replicates. Extracellular, intracellular, and total (extracellular plus intracellular) toxin levels of the wild type (WT) and the lysogen (LYS) were compared by a Student t test. Significant differences (*, P < 0.05) were observed for total and extracellular, but not for intracellular, toxins.