Mother nature designed the human being to walk barefoot over earth, mud, rocks, slime, dead things, things that are not dead, bugs, worms, miniature aliens on a short visit from the planet
xenon, etc. Your paranoia about stepping on the sidewalk is nonsense on toast. I'm not going to humor you by saying you have legitimate fears. Psychiatrists prescribe drugs and I'm not sure that's what you need.
A person does not always get an infection from a skin puncture.