Dangerous bacteria which are already resistant to antibiotics are gradually developing resistance to common alcohol-based hand gels in hospitals, a new study reports.
According to senior researcher Timothy Stinear, a molecular microbiologist at the University of Melbourne in Australia, the bacteria is called Enterococcus faecium, and is a leading cause of infections gotten from hospitals. It has fast been gaining resistance.
“It’s a WHO [World Health Organization] and CDC-recognized superbug. In the hospital it is already resistant to nearly all classes of antibiotics.”
Now E. faecium appears to be developing resistance to alcohol-based sanitizers, possibly in response to the vast use of the antimicrobial gels in hospital hand-hygiene programs. Stinear and his colleagues discovered E. faecium has adapted to hospital environment.
The team of researchers noted that E. faecium and other enterococci are bacteria found in the gut, and typically are not hostile or harmful.
However, these germs have emerged as a major cause of hospital-associated bacterial infections, the study authors noted. This family of bacteria account for a tenth of hospital-acquired bacterial infections globally, and are the fourth and fifth leading cause of blood poisoning in North America and Europe, respectively.
According to Dr. Amesh Adalja, a senior scholar with the Johns Hopkins Center for Health Security, “E. faecium is a highly prevalent bacterial species that is a very common cause of infections that ranges from bloodstream infections to urinary tract infections.” Adalja was not involved with the new study but was familiar with the findings.
“The vancomycin [antibiotic]-resistant form of this bacteria, which the CDC [U.S. Centers for Disease Control and Prevention] estimates kills more than 1,000 people a year in the U.S., is a priority pathogen that is involved in many hospital-acquired infections,” Adalja explained.
Stinear’s team collected 139 E. faecium samples between 1997 and 2015 from two Melbourne hospitals and exposed them to diluted isopropyl alcohol, to see how effectively alcohol would destroy the bugs.
Bacteria samples dating from 2009 headlong were on average more resistant to alcohol, compared with bacteria collected prior to 2004.
To ascertain whether this resistance would translate into more infections, the researchers introduced different strains of E. faecium onto the floors of mouse cages. They then wiped down the cages with isopropyl alcohol wipes, which should have successfully disinfected them.
Bacteria that had developed a resistance to alcohol sanitizers were better able to dodge disinfection and colonize the guts of mice placed in the cages, the results indicated.
Genetic investigation of alcohol-resistant bacteria found that they had developed several changes in genes connected to cell metabolism. These mutations appear to make the cellular membranes of E. faecium more impervious to solvents like alcohol.
According to Stinear;
“We were able to identify and document the specific genetic changes that have occurred in the bacteria over the 20 years, which also helps to explain the increased tolerance.”
These mutations have developed as hospitals have become more rigid in infection control, depending heavily on alcohol-based scrubs as a way to prevent harmful pathogens from spreading.
“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,” Stinear said.
Stinear suggested that to overcome this resistance, harsher hand rubs containing higher concentrations of alcohol will be required.
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Hospitals also need to ensure that hand rubs are used meticulously by staff, making sure that all skin surfaces on the hand are covered and given enough contact time to destroy the bugs, the study authors added.
“Also, there also should be an better focus on hospital cleaning as well as isolation of patients found to be colonized with” antibiotic-resistant bacteria, Stinear said.
Adalja suggested that a search should be conducted for other good antimicrobial agents that could replace ralcohol rubs.