“Did you wash your hands?” That question that kids dread may be the key to preventing the spread of a dangerous germ that is killing more people in the United States each year than the AIDS virus.

The drug-resistant staph bacterium – known as methicillin-resistant Staphylococcus aureus, or MRSA – has killed nearly 19,000 Americans and caused 94,000 serious infections in 2005, according to new Centers for Disease Control and Prevention research published in the Journal of the American Medical Association. AIDS, in comparison, has killed about 12,500 Americans.

Most of the MRSA infections appear to be traceable back to hospitals, nursing homes or medical clinics, the new CDC report found.

But a growing number of MRSA case are arising at schools and community gyms. The bacteria can live on the surfaces of objects, like countertops, for days or weeks, and be transmitted by touching it.

On Monday, after a 17-year-old Lynch Station, Va., student died from an MRSA infection, schools are taking action. In southern Virginia, 21 schools were closed on Wednesday for cleaning, although it’s not known how the student contracted the infection.

Yet, protection against the infection could be in the hands of children themselves, if we could only get them to listen. For years, I’ve been trying to get my kids to wash their hands as soon as they come into the house from school or play and before they eat. It’s been a battle, but I think I’m winning. I even lay down my “rule” on visiting friends.

Now, it turns out that the hand washing, as old-fashioned and low-tech as it seems, is a great weapon against infection. At the top of the CDC’s advice on preventing the spread of staph infections is keeping hands clean by washing thoroughly with soap and water or using an alcohol-based hand cleaner. The CDC also recommends keeping cuts and scrapes clean and covered with a bandage until healed, not touching other people's wounds or bandages and not sharing personal items like towels or razors.

So parents, don’t be afraid to be enforcers. Hold firm when it comes to clean hands.