I gotta agree with DandyDon. I do not get cold easily, but prefer to wear full suits for skin protection. As for the bacteria, any bacteria can cause serious injuries under the right conditions. While I am not familiar with bacteria found only in salt water, as a used to be Medical Technologist, I have found bacteria which is normal in some areas be quite lethal if placed into the part of the body and the body is already under immunological stress. Anyway, my 2 cents.. Wearing some kind of protection suit will lower the risk of infections.