Fig. 1. Acid resistance phenotypes of Shiga toxin-producing Escherichia coli isolates. (A) The RNA polymerase sigma factor (RpoS)-induced acid resistance (AR) phenotypes (AR1; upper panel) and western blotting with anti-RpoS antibody (lower panel). (B) The glutamate-induced AR phenotypes (AR2; upper panel) and western blotting with ant-GadA (glutamic acid deoxycarboxylase A) antibody. Lane 1, EDL933; lane 2, 85-170; lane 3, B2006-11; lane 4, B2006-29; lane 5, B2007-75; lane 6, B2007-76; lane 7, P2010-19; lane 8, P2010-23; and lane 9, P2010-29. Significantly different from EDL933 (^**p < 0.01, ^***p < 0.001).