At hospitals around the world, staff dutifully slather on hand sanitizer to prevent the spread of infections. But now, at least one type of bacteria in hospitals appears to be growing more tolerant to alcohol-based hand sanitizers, a new study from Australia suggests.
The study focused on a bacterium called Enterococcus faecium, which is already resistant to some antibiotics and is a leading cause of hospital-acquired infections, such as urinary tract infections and sepsis. In fact, infections with drug-resistant E. faecium have been increasing in recent years, despite the growing use of hand sanitizers in hospitals, the researchers said.
The study found that over a nearly 20-year period, strains of E. faecium became better able to withstand alcohol-based hand sanitizer, meaning the sanitizer didn't kill the bacteria as well as it had before. [6 Superbugs to Watch Out For]
Still, the findings don't mean that hospitals should ditch the hand sanitizer.
"Alcohol-[based] hand-hygiene programs have been highly successful, particularly at controlling MRSA [methicillin-resistant Staphylococcus aureus], but also other types of hospital infections, and I would strongly advocate that we continue" using hand sanitizer, study co-author Dr. Paul Johnson, an infectious diseases professor at Austin Health in Victoria, Australia, said in a video about the study findings.
But to control certain pathogens, such as drug-resistant E. faecium, hospitals may need to add new measures, such as the use of other disinfectants, perhaps chlorine-based ones, the researchers said.
For the study, the researchers analyzed 139 samples of E. faecium bacteria collected between 1997 and 2015 from two hospitals in Melbourne.
Samples collected after 2010 were 10-fold more tolerant of alcohol-based sanitizers, compared with older samples, the researchers wrote in their paper, published Wednesday (Aug. 1) in the journal Science Translational Medicine.
The researchers analyzed DNA from the bacterial samples and found that the samples with more tolerance to hand sanitizers had several mutations in genes involved in metabolism. This resulted in increased resistance to alcohol.
The findings might explain the recent rise in drug-resistant E. faecium infections in hospitals, the researchers said.
Still, the researchers noted that because the study was conducted in only two Australian hospitals, more studies are needed to see if the same phenomenon is happening in other parts of the world.
"We are very keen to see whether the same patterns of alcohol tolerance are in [drug-resistant E. faecium] populations in other hospitals worldwide," study co-author Tim Stinear, a professor in the University of Melbourne's Department of Microbiology and Immunology, said in the video.
In addition, the researchers can't say for sure what's causing the bacteria's increased tolerance to alcohol. Although the findings suggest that the use of alcohol-based sanitizers in hospitals may play a role, it's possible that other factors, such as adaptations to better survive in people's guts, coincidentally led to increased alcohol resistance, Stinear said.
The researchers are now examining exactly how the genetic mutations found in this study cause increased tolerance to alcohol.
Original article on Live Science.
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Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.