Staph infections are caused by Staphylococcus (staph) bacteria and can result in a wide variety of conditions and diseases. Staph bacteria are commonly found on the skin and in the nasal cavities without causing an infection. Disease may result when the bacteria are able to invade the body because there are breaks in the skin or the immune system is suppressed.

Most staph infections cause only minor skin problems, such as pimples and boils. More serious conditions that may be caused by staph bacteria include:

• Skin diseases such as impetigo and cellulitis
• Pneumonia
• Osteomyelitis (bone infection)
• Endocarditis (heart infection)
• Toxic shock syndrome
• Food poisoning

Staph bacteria may be transmitted through the air, via contaminated objects or surfaces, and from person to person. Staph infections frequently occur during medical procedures and hospital stays, but outbreaks can also occur in schools and other places.

Staph infections may be treated with antibiotics, although some staph bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), have developed resistance to many medications. MRSA first appeared in healthcare facilities but is being increasingly found in communities. About 94,000 Americans developed a serious MRSA infection in 2005, with more than 18,000 deaths, according to the Centers for Disease Control and Prevention (CDC).

However, most staph infections, including MRSA, are much less serious. The majority involve local skin infections and symptoms such as boils. Minor staph infections may not require antibiotics at all, just professional drainage and cleaning.

Staph infections can often be prevented with proper personal hygiene, including frequent hand washing and not sharing towels or razors, and proper wound care. It is also important not to misuse antibiotics. Recent research of an experimental vaccine successfully provided short-term protection against certain types of MRSA among some subjects.