There are bacteria which naturally use wires. For example to strip electrons off of metal nodules (the videos are amazing, you can see the bacteria attach to the nodule, the metal shrinks, and you see the Schlieren effect of the high concentration of dissolved ions).

AIUI the biggest obstacle is likely the fact that bacteria want to operate in a high current, low voltage regime and everything we do with bulk power wants to operate in a low current high voltage regime.