The proliferation of computers in medical settings has meant not just technological innovation but a new source of potentially lethal infections: keyboards used by doctors and nurses who don't wash their hands.

That's what a team of infectious-disease specialists at the Tripler Army Medical Center in Honolulu discovered when they cultured 10 computer keyboards in the intensive-care unit eight times over two months. About 25 percent of the samples harbored the bacteria hospital officials fear most: multidrug-resistant staphyloccocus aureus.

This type of bacteria, once easily vanquished by penicillin, is responsible for about 95 percent of hospital-acquired infections nationwide, according to the federal Centers for Disease Control and Prevention. It can spread rapidly, particularly among patients with weakened immune systems.

DNA tests revealed the same strain of drug-resistant staph was found in two patients during the two-month test period. Researchers also detected enterococcus on intensive-care unit keyboards; enterococcus can cause life-threatening gastrointestinal infections.

The search for germ-infested keyboards was inspired by a suspicion that keyboards may be unrecognized reservoirs of harmful bacteria, according to Tripler physicians whose findings were published in the American Journal of Infection Control.

For years, researchers have known sinks, faucet handles, countertops and disposable gloves can harbor germs, but until the recent explosion in the use of computers in all facets of medicine, keyboards had not been considered.