PE-deficient E. coli mutant out-survives the WT against the membrane-active antimicrobial. (A) Microbicidal assays show that, in the presence of the membrane-active phenylene ethynylene-based antimicrobial, the survival of the fragile PE-deficient mutant strain AD93 is much greater than that of its WT parent strain W3899 (≈3 orders of magnitude at 4 μg/ml) in sterile buffer solution (10 mM Hepes, 60 mM NaCl, 100 μM MgCl2, and 400 mM sucrose, pH 7.5). (B) When being exposed to tobramycin, a conventional antibiotic that targets the ribosome rather than the bacterial membrane, the WT parent strain (W3899) survived at a drastically higher rate than the mutant strain (AD93) (≈4 orders of magnitude at 1 μg/ml) in sterile buffer solution (10 mM Hepes, 60 mM NaCl, and 200 μM MgCl2, pH 7.5). Data points are reported as mean ± standard deviation.