Hand sanitizers becoming less effective against some bacteria, study says

Using hand sanitizer over and over again can make it less effective against some bacteria, according to one study. (Photo by John Moore/Getty Images)

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Using hand sanitizer over and over again can make it less effective against some bacteria, according to one study. (Photo by John Moore/Getty Images)

Hand sanitizers are generally a convenient way to keep germs at bay, but they are becoming less effective, according to a new report.

While the disinfectants have helped battle staph infections and some drug-related bacteria in patients, Australian doctors have noticed a rise in hospital-acquired infections of enterococcus faeciuma bacteria that can affect the digestive tract, bladder and heart.

Because of this, researchers from health institutions in Australia conducted a study, published in Science Translational Medicine Aug. 1, to determine the potency of alcohol-based hand sanitizers.

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To do so, they analyzed 139 bacterial samples from two hospitals that were collected over the course of 19 years. They assessed how long the samples survived after being exposed to diluted isopropyl alcohol.

"We started testing to see whether they had any tolerance to alcohol, and sure enough, the new isolates were more tolerant to alcohol exposure than the older isolates," lead author and professor Tim Stinear, of the Peter Doherty Institute for Infection and Immunity in Melbourne, Australia, said in an article on the study.

Researchers found isolates gathered after 2009 were more tolerant to alcohol-based sanitizers than bacteria taken before 2004. In fact, they discovered enterococcus faecium strains that have emerged since 2010 have become 10 times more tolerant to alcohol-based hand rubs than older strains.

“Anywhere we repeat a procedure over and over and over again, whether it’s in a hospital or at home or anywhere else, you’re giving bacteria an opportunity to adapt because that’s what they do, they mutate,” Stinear explained. “The ones that survive the new environment better then go on to thrive.”

Despite their findings, the analysts noted alcohol-based hand sanitizers and other clinical settings should still be used.

“This isn’t the end of hospital hand hygiene, that’s been one of the most effective infection control procedures that we’ve introduced worldwide,” Stinear said. “But we can’t rely solely on alcohol-based disinfectants, and for some bacteria, like VRE (vancomycin-resistant enterococci), we’re going to need additional procedures and policies in place.”

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