But those measures require actions by human beings — which is not the case with copper.

“It’s always working, it requires no human intervention, no supervision, and it’s acting continuously,” said Michael Schmidt, a microbiology professor at the Medical University of South Carolina and one of the researchers who conducted the first and largest study of copper surfaces in hospitals.

Besides the South Carolina hospital, the study involved Memorial Sloan Kettering Cancer Center in New York and the Veterans Affairs hospital in Charleston, S.C. About 600 patients who were admitted to the intensive-care units at the facilities were randomly assigned to receive care in traditional patient rooms or ones in which six frequently touched objects — such as bed rails, tables, IV poles and nurse call buttons — were made from copper alloys.

While welcoming the findings, researchers said additional studies are needed to answer many questions.

“Is there a minimal risk number out there — how many bacteria on a surface to really put people at risk?” said L. Clifford McDonald, a medical epidemiologist at the CDC.

“Right now, there’s not enough data on copper or other technologies to make firm recommendations on what hospitals should do,” he said. In the meantime, facilities should continue to thoroughly clean patients’ rooms and supplement that with disinfectants. And everyone, especially health-care workers, should wash their hands with soap and water.

At an American Hospital Association conference in July, Todd Linden, chief executive of Grinnell Regional Medical Center in Iowa, gave a 70-minute presentation on copper items installed in 13 of the hospital’s patient rooms. The 49-bed facility also plans to use copper in renovating its emergency room. Grinnell College biology professor Shannon Hinsa-Leasure is conducting a clinical trial on the hospital’s use of copper. The hospital’s fitness center also has copper components, including on its free weights. Olin Brass and its manufacturing partners donated products for the hospital; community donations paid for the fitness center.

Cost is an issue. Adding copper surfaces is about 15 to 20 percent more expensive than using traditional stainless steel. But the long-term benefits are worth it, Linden and Schmidt say.

A typical U.S. hospital room contains about $100,000 of goods and equipment, experts say. The average cost to outfit a hospital room with antimicrobial copper items is about $5,000, Linden said. But one infection adds $43,000 in patient costs, according to federal data. And under the Affordable Care Act, hospitals with higher infection rates and other patient injuries face decreases in their Medicare reimbursements.

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The copper industry, meanwhile, provided financial help to several facilities interested in experimenting with copper surfaces.

The Copper Development Association gave $50,000 in grants to four hospitals in 2013 and 2014, said Adam Estelle, a project engineer with the trade group.The association began promoting copper’s antimicrobial properties in 2008, when several groups of copper products met standards of the Environmental Protection Agency to be registered as antimicrobial and effective in killing six types of bacteria, including MRSA, VRE and the deadly E. coli 0157 strain, the culprit in numerous food recalls, illnesses and deaths.

Pullman Regional Hospital in Washington state received a $10,000 grant from the copper industry group two years ago. The 26-bed hospital bought more than 1,200 cabinet drawer pulls and 22 handicapped-access buttons on doors.

Ed Harrich, chief of surgical services, and his staff have been methodically installing the hardware. He persuaded hospital administrators to approve another $10,000 for more items.

“If you looked at my cabinet pulls, they look like stainless steel, but we still get copper’s killing properties,” he said. “We’re still continuing to clean everything we can. But this is our little helper behind the scenes.”