It's estimated that 32 of every 100,000 Americans will get infected, an "astounding" figure, according to the Journal of American Medical Association. A staff member at Phoenix Union High School District had the infection about a month and a half ago, according to state health officials.

The district responded with mass disinfecting and sanitized all of their facilities for three weeks. It also sent letters home to parents stressing the importance of hygiene. "We had to make sure kids washed their hands," said Craig Pletenik with the school district.

"We had to make sure they were taking showers after physical education classes and athletic events," he said.

The infection can be spread by skin-to-skin contact or sharing an item used by an infected person, particularly one with an open wound.

In Bedford County,Va., schools are undergoing a cleaning following the death Monday of a 17-year-old high school student who was diagnosed with MRSA.
Staph infections, including the serious MRSA strain, have been spreading through schools nationwide in recent weeks, according to health and education officials.
Many of the infections nationwide are being spread in gyms and locker rooms, where athletes -- perhaps suffering from cuts or abrasions -- share sports equipment, physicians said.

The bacteria don't respond to penicillin-related antibiotics once commonly used to treat them, partly because of overuse. They can be treated with other drugs but health officials worry that their overuse could cause the germ to become resistant to those, too.

Researchers found that only about one-quarter of invasive cases involved patients in hospitals. However, more than half were related to health care, occurring in people who had recently had surgery or were on kidney dialysis, for example. Open wounds and exposure to contaminated medical equipment are major ways the bug spreads.

There were 988 reported deaths among infected people in the study, for a rate of 6.3 per 100,000. That would translate to 18,650 deaths annually, although the researchers don't know if MRSA was the cause in all cases.

If these deaths all were related to staph infections, the total would exceed other better-known causes of death including AIDS -- which killed an estimated 17,011 Americans in 2005 -- said Dr. Elizabeth Bancroft of the Los Angeles County Health Department, who wrote an editorial published with the study in Wednesday's Journal of the American Medical Association.