Dangerous bacteria that pose a particular threat to the elderly and very sick hospital patients have been shown to survive on disposable hospital gowns and stainless steel surfaces — even after they're scrubbed clean.

The bacteria, called Clostridioides difficile or C. diff., cause almost a half million infections every year in the United States, according to the Centers for Disease Control and Prevention. An estimated 29,000 of those infected die.

The infection, which is spread by fecal to oral transmission, causes severe diarrhea, and can lead to intestinal inflammation and kidney failure. Those most at risk are people who have been given strong antibiotics, as well as those with long hospital stays, or those living in long-term care facilities like the elderly.

That means that keeping these facilities clean is incredibly important. But new research, published Friday in the journal Applied and Environmental Microbiology, shows how difficult that can be.

In lab studies, researchers found that C. diff spread easily from disposable gowns often employed in surgery or infection control to stainless steel and vinyl surfaces.

"The [bacteria] also transferred to vinyl flooring, which was quite disturbing. We didn't realize they would," said Tina Joshi, a lecturer in molecular microbiology at the University of Plymouth in the United Kingdom and lead author of the new study.

These bugs evolve. These bugs like to stay one step ahead. And even though we're using disinfectants and antibiotics appropriately, they still will become resistant in time. It's inevitable.

What's more, the bacteria didn't die when the researchers tried to kill them with concentrated chlorine disinfectant.

"Even if we applied 1,000 parts per million of chlorine, it would allow spores to survive in the gowns," Joshi told NBC News.

It's possible that increasing the amount of chlorine might kill the spores, but if the spores are indeed becoming resistant to the disinfectant, it will only be a matter of time before the stronger concentrations can't kill them.

"These bugs evolve. These bugs like to stay one step ahead. And even though we're using disinfectants and antibiotics appropriately, they still will become resistant in time. It's inevitable," Joshi said.

C. diff infections can occur when a patient is given broad spectrum antibiotics to tackle another infection.

Those antibiotics can wipe out a person's gut bacteria, but C. diff survive. That allows the bacteria to proliferate throughout the gut, and eventually come out in feces. If a person has severe diarrhea, for example, the bacteria can be launched into the air and spread around a room. That's when it's imperative to decontaminate clothing, curtains, tables and the bed.

If the bacteria aren't killed, hospital patients or people in nursing homes can become infected when they come into contact with contaminated surfaces, such as a bedside food tray.

But if traditional disinfectants are ineffective, as the new research suggests, what works?

One option is UV light, which could be useful in killing the bacteria. However, it can be challenging to make sure all surfaces are fully exposed to the light. At this point, Joshi said, highly concentrated bleach appears to be the best option.

For those who care for patients with compromised immune systems at home, the C. Diff Foundation says alcohol-based hand sanitizers are ineffective against the bacteria.

On its website, the group recommends instead using a cleaning solution of one cup bleach to nine cups of water, and leaving the mixture on surfaces for a minimum of 10 minutes.

Meanwhile, if C. diff spores can survive on gowns and other surfaces, it is likely also the case that they can live on doctor's coats and scrubs worn by hospital personnel all day.

"That's a real infection control hazard, because these spores can stick to fibers. We've proven that in this paper," Joshi said.

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