Final answer:
Staphylococcus epidermidis and Clostridium tetani are examples of microbes with naturally reduced virulence for humans, with the former being generally avirulent on healthy skin and the latter living in soil but causing tetanus when introduced to a wound.
Step-by-step explanation:
An example of a microbe with a naturally reduced virulence for humans is Staphylococcus epidermidis. This bacterium is part of the normal skin flora and is generally avirulent in healthy individuals. However, it becomes an opportunistic pathogen in hospitals where it can cause serious infections, especially when it forms biofilms on medical devices and implants. Another example of a microbe with typically low human virulence is the bacterium Clostridium tetani, which, when it gets into a wound and is surrounded by anoxic conditions, can multiply and release a toxin causing tetanus.