Is staphylococcus aureus good or bad for people?

S.aureus is a Gram positive bacteria. It can have a commensal relationship with a person. Meaning that one organism benefits but there is no harm nor benefit to the other organism.

S.aureus is found, in some, in the skin flora, the nose, and less frequently in the throat. In some individuals no harm is found.

In other individuals S.aureus is harmful leading to things such as cellulitis, pneumonia, or other myriads of of diseases.

In short S.aureus is more harmful than good.