Bacteria is anywhere and everywhere. The only place that does not contain a lot of bacteria are those areas that have been sterilized in laboratory environments and research facilities and occasional hospital environments. So, what do we do about it? Good question. The answer is that we try our best to avoid contact with large amounts of bacteria that may make us sick. The sources that are most likely to make us sick would likely enter through our mouths, through breathing, anus, sexual activity, or through wounds or open cuts. Another think that will spread bacteria are living organisms such as plants and animals. I am assuming that much of what I am talking about here you already know about.
An animal or thing which carries a disease is called a “vector.” The most commonly thought of vectors are ticks and mosquitos but there are lots of other vectors. Vector borne diseases account for more than 17% of all diseases. Flies, snails and fleas are all vectors.
The thing to really watch out for in the United States are the simple things that they really don’t think much about in other parts of the world. It is best not to reuse the water container that you use for drinking unless you are absolutely certain it is sterile. Rubbing alcohol and Hydrogen Peroxide may not necessarily sterilize a water bottle, but they may. Boiling a metal water bottle in water might work, but then again, it may not. What really needs to be done with a surface that is regularly exposed to moisture is that it needs to be cleaned. This needs to be done with mechanical action…… scrubbing of the surface should most likely work. It is also good to use some type of antimicrobial substance such as soap, rubbing alcohol, vinegar, etc…
I would suggest that you not reuse water bottles as a way to transport your water unless it is an open cup that you then put into the dishwasher when you are done with it. If you do not clean your water receptacle properly it can breed bacteria, viruses and other pathogens.
Being careful of the food that you eat and how well it is cooked is a good idea. Meat should be properly cooked. Sushi contains parasites. Good luck with the sushi. Don’t say I did not warn you. It is best to err on the side of caution.
As if this was not already obvious, it might also be a good idea to be cautious of who you have sex with and how you have sex with them. STDs can be quite deadly in certain circumstances.