contaminated. i then don't wash my hands and go talk to the second patient or examine the second patient. and i introduce that infection into that second patient. and in many senses we're no different than a mosquito causing malaria. we're, you know, a vector introducing harm rather than protecting patients. >> another way -- a needle pierces dirty skin. >> your skin is an amazing defense against bacteria. but when i break that skin, i allow bacteria to enter. >> hospitals kill 100,000 people a year with these infections. it may be uncomfortable to ask, but make sure doctors and nurses wash their hands before they touch you, even if they're wearing gloves. at number 3, metal in the mri room. 6-year-old michael columbini has brain cancer. he's getting an mri. >> an mri machine is a very large, very, very powerful magnet.