WASHINGTON (Reuters) - The mutated, drug-resistant "superbugs" that cause an increasing number of hospital infections and deaths can live for weeks on bed linens, computer keyboard covers and under acrylic fingernails, U.S. researchers reported on Monday.

The study supports other research that shows super-strict hygiene is needed to battle the bacteria, some of which are now nearly impossible to kill even with the strongest antibiotics.

A team at sanitation-services company Ecolab Inc. dabbed methicillin-resistant Staphylococcus aureus onto samples of bed linen, keyboard covers and acrylic fingernails.

MRSA could be detected eight weeks later on acrylic fingernails, six weeks later on computer keyboard covers and five days later on bed linens, the researchers told a meeting in Atlanta of the American Society for Microbiology.

"The results of this study clearly demonstrate the need for frequent hand washing and environmental disinfection in health care settings," said researcher Kris Owens of Mendota Heights, Minnesota-based Ecolab.

Staphylococcus aureus is usually harmless and very common, found on skin or in the noses of about 30 percent of people. It can cause stubborn problems such as rashes and boils and an infection is often mistaken for a spider bite.

In hospitals, MRSA can cause serious and sometimes deadly infections, including necrotizing fasciitis or "flesh-eating" disease. It resists almost everything but an intravenous antibiotic called vancomycin.

A study at Northwestern Memorial Hospital in Chicago, published in April, found that computer keyboards can contaminate the fingers, bare or gloved, of a nurse or doctor, who could then transfer bacteria to patients.