http://www.kidshealth.org/parent/infections/bacterial_viral/staphylococcus.html
Many healthy people carry Staphylococcus aureus (staph) bacteria in their noses without getting sick. But when the skin is punctured or broken, staph bacteria can enter the wound and cause infections, which can lead to other health problems. Learn how staph infections spread, are treated, and steps you can take to prevent your child from becoiming infected.