Amongst them, especially Enterococcus faecium shows signs of drug resistance, which made this species a ideal subject of study for the scientists.
VRE bugs can cause urinary tract, wound and bloodstream infections that are notoriously hard to treat, mainly because they are resistant to several classes of antibiotics. A team of researchers at the Peter Doherty Institute for Infection and Immunity in Melbourne studied Enterococcus faecium, a strain of bacteria that's a common nuisance in hospitals, but not particularly deadly. "Alcohol-based hand hygiene use has increased 10-fold over the past 20 years in Australian hospitals, so we are using a lot and the environment is changing".
"Alcohol-based hand rubs are worldwide pillars of hospital infection control and remain highly effective in reducing transmission of other hospital superbugs, particularly MRSA", he said. The results clearly show that bacteria gathered before 2004 had much lower survival rate than those collected between 2009 and 2015. They then took hospital-grade disinfectant wipes, wiped down the cages, and let mice crawl around inside for an hour.
This alarming development prompted Sacha Pidot and colleagues to investigate whether E. faecium could be developing resistance to the alcohols used in hand rubs. Subsequent testing revealed that mice exposed to the alcohol-tolerant samples were more likely to have Enterococcus faecium colonizing in their guts.
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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.
However, drug-resistant E. faecium infections have increased despite the use of alcohol disinfectants, and now represent a leading cause of infections acquired in hospitals.
Being "tolerant" means the bacteria can survive exposure to alcohol longer.
Treatment-resistant bacterial species such as methicillin-resistant Staphylococcus aureus have become an increasing source of concern for hospital workers over the past several decades. In the meantime, the researchers say, hospitals might want to consider using disinfectants with both alcohol and chlorhexidine, another bacteria-killing compound, to try and cut down on the spread of alcohol-tolerant bugs. "However ... we may have to add additional control measures for VRE outbreaks".