Novel chromogenic medium-based method for the rapid detection of Helicobacter pylori drug resistance

Figure 2 The discoloration reaction observed in Helicobacter pylori cultures following the addition of urea and phenol red. 0.2-0.8 mg/100 mL phenol red had no influence on Helicobacter pylori growth. However, when 0.2 mg/100 mL phenol red was added to the medium, the cultured Helicobacter pylori (1 × 105 CFUs/mL) showed minimal color change. The medium turned light red with the addition of 40 mg, and dark red with 80 mg.