Does E. coli survive at any pH level?
I assume you are asking if E. coli can survive extreme pH conditions and according to this study E. coli K-12 W3110 survives at pH 1.2 – pH 2.0 under low oxygen. This study cultured different strans overnight and exposed to pH 2.0 for 2 hours before diluting 1:80,000 and 1:400,000, under anoxic and aerated conditions. Dilutions where then plated allowing colonies to grow up overnight at 37 oC so this study measured survival as far as I can tell. E. coli can demonstrate robustness and E. coli survives and grows 'accustomed' at pH 7-8 based on the paper here. However it would be great if you clarified your agar pH and the E. coli genetic background you are interested in if you have a specific question about its particular limits (growth or survival).