A method of determining antimicrobial activity of an agent can include providing a well, wherein the well contains at least one antimicrobial agent, the well further including at least two electrodes. A sample of a microbe can be added into the well and a voltage pulsed between the electrodes. An electrical property can be sampled and recorded. In another aspect, a method of identifying at least one microbe includes taking a sample containing the at least one microbe, isolating the at least one microbe from the sample, dividing the at least one microbe into a at least one well, wherein each well contains at least one antimicrobial agent and at least two electrodes. A voltage is pulsed between the at least two electrodes, an electrical property is sampled during the pulsing and recorded. In another aspect, a diagnostic device for detecting at least one microbe is presented.