Many people travel with their own supply of water and an industrial vat of hand sanitizer. I can say in full honestly that I have never used hand sanitizer or gone out of my way to avoid contact with germs during my travels. It is true that in many places you can get nasty illnesses from drinking untreated water, but I don’t think this means you have be a traveling Howard Hughes. Unless you have a particularly weak immune system or other illness, I wouldn’t worry too much about local bugs.