Staphylococcus aureus [staf I lō-kok is aw ree us] (staph), is a type of bacteria that about 30% of people carry in their noses.Most of the time, staph does not cause any harm; however, sometimes staph causes infections.In healthcare settings, these infections can be serious or fatal, including:revention of Staphylococcus aureus infection. CDC has published guidelines and recommendations that healthcare professionals should follow to prevent the spread of staph and other bacteria in their healthcare facilities (see recommendations and guidelines below).