The Grapevine

Some Bacteria Becoming Resistant To Hand Sanitizers, Study Finds

Certain strains of bacteria may be developing a resistance against alcohol-based hand sanitizers, a new study from Australia found.

The report titled "Increasing tolerance of hospital Enterococcus faecium to handwash alcohols" was published in Science Translational Medicine on Aug. 1.

Since 2002, several hospitals in Australia began implementing dispensers to promote the use of alcohol-based hand sanitizers, known to be effective in preventing healthcare-associated infections.

Over the years, while the rates of certain infections decreased, it was found that certain hospital infections actually started increasing. One example being enterococcal infections caused by Enterococcus faecium or E. faecium.

A rising number of cases in this type of infection were observed in countries around the world, not just Australia. This was despite the growing, widespread use of hand sanitizer at hospitals.

To understand why, the research team decided to test sanitizers containing varying levels of alcohol against bacteria samples. They started with a solution containing 23 percent alcohol and slowly moved up.

It was only when they tested the solution with 70 percent alcohol that the bacteria was killed off. Hand sanitizers typically contain around 60 percent alcohol.

Co-author Timothy Stinear, a researcher at the University of Melbourne's Doherty Institute for Infection and Immunity, stated this may be the first time hospital bacteria was shown to become resistant to alcohol.

When comparing the strains gathered by the researchers, the bacteria collected after 2009 were found to be ten times more tolerant than bacteria collected before 2004.

To mimic exposure the way it would occur in the real world, E. faecium was also exposed to mice that lived in cages disinfected with an alcohol antiseptic. According to Gizmodo, the team examined the poop pellets of the mice and found that alcohol-tolerant strains actually thrived more under these conditions.

Lance Price, a professor from George Washington University, who was not affiliated with the study, was surprised by the findings as he always thought of alcohol as being like a sledgehammer.

"But clearly, these are innovative organisms. And evolution happens pretty fast when you're dealing with populations that can double every 30 minutes and travel in packs of billions," he said.

"We have to be careful about this new trend towards heavy reliance on alcohol-based hand sanitizers," he added. "Soap and water should be our number-one protection."

The findings do not indicate that we should discard hand sanitizers just yet. Alcohol-based sanitizers may be more effective in some cases, such as the strains that cause staph infections.

The researchers encouraged the proper use of hand sanitizers which could help reduce the likelihood of the bacteria becoming more tolerant. This meant opting for liquid solutions and rubbing hands until they feel dry, which usually take around 20 seconds.