FIG 2.

The effect of hydrogen peroxide (H₂O₂) on H. pylori. (A) OD₆₀₀ of H. pylori colony suspensions in Columbia blood agars containing a series of concentrations of hydrogen peroxide. Colloidal bismuth subcitrate (CBS) 7.3 mg/ml was the positive control, and normal saline (NS) solution was the negative control (n = 5). (B) OD₆₀₀ of H. pylori suspensions in special peptone broth containing a series of concentrations of hydrogen peroxide (n = 7). (C) OD₆₀₀ of H. pylori suspensions in special peptone broth containing hydrogen peroxide as follows: 1.0 mg/ml for ATCC 43504; 0.3 mg/ml for wild type I; 0.5 mg/ml for wild type II; and 1.2 mg/ml for wild type III, with H. pylori inoculum concentrations of 1 × 10⁶, 10⁷, 10⁸, and 10⁹ CFU/ml, respectively (n = 7). Values given are mean ± SE; *, P < 0.05; and **, P < 0.01 versus control, as determined by one-way ANOVA and Student’s t test.