For all the images of healthy, joyous activity competitive athletes may conjure up, sports can be a germy business.

At any moment, about a third of all people in the United States are carrying some strain of staph germ on their skin or in their nasal passages. Normally, this isn't a concern if you have a healthy immune system and intact skin.

But if the skin gets broken, even by the smallest scratch or scrape, bacteria resistant to a large spectrum of antibiotics may enter, and you've got a serious medical problem in the making.

Contact sports like wrestling, football and rugby have some of the highest incidence of skin infections linked to sports, but the risk is present for athletes taking part in everything from cheerleading and gymnastics to golf and tennis.

The burden is substantial. One review of reported infectious diseases in sports found that skin diseases accounted for 56 percent of all documented cases between 1922 and 2005.

One thing that's clear is that it's better to prevent a drug-resistant skin infection than be forced to treat it with costly and complex antibiotics.

"We're paying a huge cost, in every sense of the word, from skin diseases," said Steven Zinder, an athletic trainer and assistant professor of exercise and sports science at the University of North Carolina, Chapel Hill.

He led a six-year review of the problem for the National Athletic Trainers' Association that concluded with the publication of recommendations and guidelines for avoiding, identifying and treating skin infections among athletes at all levels.

Many of the prevention recommendations are simple -- "stuff we learned in the sixth grade," Zinder said:

»  Regular cleaning of locker rooms, practice and competition courts, mats and artificial turf fields, as well as gear.

»  Athletes and coaches need to be educated about and encouraged to follow good hygiene. That means washing and showering regularly and promptly -- not waiting for hours to go home and shower there. Athletes need to make regular health checks of their skin.

»  Discouraging athletes from sharing towels, water bottles, athletic gear, or personal care items like razors or hair clippers.

»  Laundry and gear need to be washed or disinfected on a daily basis. And if stuff comes home to be washed in a gym bag, make sure the bag gets cleaned, too.