Sensitivity of Edwardsiella piscicida to acid stress. A TX01, TX01ΔhutZ, and TX01ΔhutZC were cultured in LB medium and on LB agar plates at pH = 7 and pH = 5 at 28 °C for 24–48 h. B Bacteria cultured to logarithmic stage were transferred to LB medium at pH = 5, and the populations of cultivated bacteria were counted by dilution plating. Data are the means of three independent experiments and are presented as the means ± SEMs (N = 3). N, the number of times the experiment was performed. **P < 0.01.