Since staph bacteria can live almost anywhere, the ways it can lead to infection are numerous. It can live in improperly sanitized medical equipment, in hot climates, in salty food items -- even cooking contaminated food won't kill it because the bacteria can survive high temperatures. Food poisoning comes from eating infected food, which can occur if the dish is prepared by someone carrying staph bacteria or if the food was left sitting out for too long.
The way staph bacteria infect your body is no different than the way any other type of infection works. The bacteria make their way into your system, often through an open wound. From there, the bacteria can enter the bloodstream, causing blood poisoning, and even the digestive system, which results in food poisoning -- even if you are otherwise healthy. Once the bacteria get inside your body, they cause an infection, which can range from small boils to heart failure depending on how and where they're taken into your system, but we'll talk more about symptoms in the next section.
One place staph has been known to thrive is in hospitals. As patients come in and out with a variety of wounds and weakened immune systems, and especially with the widespread use of invasive devices like feeding tubes, catheters or dialysis, the bacteria can often find this an easy area to slip in, because they're consistently opened wounds. Unsanitary conditions such as improper hand washing and non-sterilized surfaces can lead to the transfer of staph bacteria at some hospitals, especially since people may carry the staph bacteria unknowingly.
Staph can also be spread simply by skin-to-skin contact, so people living in group situations such as dorms can be easily infected, too. For these same reasons, contact sports, such as football and wrestling, are also known for spreading staph. Between 2005 and 2008, six different players for the Cleveland Browns got staph infections. It even affected two of the highest profile players in football, Peyton Manning and Tom Brady, in 2008 [source: Gregory].
Having a low white-blood cell count makes you an easy target for a variety of infections, staph included. Since white-blood cells defend against infection, having fewer of them means staph can infect your system more easily.
Basically, anyone can be at risk for staph infections, but what is it going to be like if you get one? We'll answer that question in the next section.