Some hospital superbugs are growing increasingly tolerant to alcohol-based disinfectants found in hand washes and sanitisers, allowing increasing infections to take hold, according to an Australian study.
Hand rubs and washes that contain disinfectants based on isopropyl or ethyl alcohol are widely used around the world, and have cut down dramatically on one type of superbug, called methicillin-resistant Staphylococcus aureus (MRSA). But researchers have noticed a rise in another kind of bacteria that lives in the gut, called Enterococcus faecium, and can be spread via catheters, ventilators or central lines in a healthcare setting.
“Drug-resistant E. faecium infections have increased despite the use of alcohol disinfectants, and currently represent a leading cause of infections acquired in hospitals,” said the report in the journal Science Translational Medicine.
Enterococci account for about one in 10 cases of hospital-acquired bacterial infections around the world, and are the fourth and fifth leading cause of sepsis in North America and Europe, respectively, according to background information in the article. E. faecium in particular is believed to cause one-third of enterococcal infections in Australia, 90% of which are resistant to the antibiotic ampicillin, and 50% of which are also vancomycin-resistant.
Being “tolerant” means the bacteria can survive exposure to alcohol longer. The delay “is sufficient to allow the bacteria to escape alcohol killing and then cause infection,” says study author Tim Stinear, a microbiologist at the Doherty Institute for Immunity and Infection at the University of Melbourne. “The bacteria we examined in our study are a long way from becoming resistant to alcohol,” he added.
More study is needed to confirm if these bacteria are also growing resistant to sanitisers in other hospitals worldwide. Researchers aren’t sure why this particular type of bacteria is acting this way, but say it may be something about the physiology of E. faecium that makes it easier for the bacteria to evolve tolerance to alcohol exposure. In the meantime, no one is suggesting hospitals stop using hand sanitisers, rather that other cleansing methods are needed, said Stinear.
“Our findings do not signal the end of hand sanitisers, but indicate you cannot rely solely on alcohol-based disinfectants to control E. faecium in the hospital/health-care setting.”