(a) The threshold of electric field, Ec, required to inactivate P. aeruginosa by PEF and antibiotics. For antibiotic mix treatment only, we calculated the equivalent Ec from the observed radius of inactivation. Dil 1–5 are as described in Table 3. n = 63. (b) Digital image of a plate with PEF: 1,750 V, 200 pulses, 60 μs pulse length, 350 ms pulse interval combined with Pen G 5,000 units/mL, Strep 5 mg/mL, Nys 625 units/mL (Dil 1). (c) Digital image of a plate with PEF: 1,750 V, 200 pulses, 60 μs pulse length, 350 ms pulse interval combined with Pen G 500 units/mL, Strep 0.5 mg/mL, Nys 62.5 units/mL (Dil 5). Dil, dilution; Nys, Nystatin; Pen, Penicillin; Strep, Streptomycin.