Yes; fecal transplants are used often for people to recolonize bacteria lost to prior use of antibiotics.There is such a thing as fecal transplants, that can be life saving for some people with antibiotic resistant infection. Gives an entirely new meaning to give a sh*t... There is also such a thing as ear wax transplant from one person to another which helps treat chronic external ear infections. So getting someone else’s oral bacteria especially in a situation of emergency is not that big of a deal Many are concerned about COVID and maybe rightfully so. However, there are Herpes, HPV and other things that once you get may cause a lifelong infection and probably more likely than corona to stick on the moist surface longer.
You are correct @Ukmc; we are surrounded by pathogens including bacteria, viruses and fungi. Even in seawater here is a common pathogen; vibrio vulnificus. But unless we are immunocompromised, we are not defenseless.