Enterococcus faecium, a bacterial species resistant to multiple drugs that can cause infections in hospitals, is becoming increasingly tolerant to the alcohols used in hand sanitizing disinfectants.
Nosocomial infections, those acquired during a hospital stay, represent a serious global health problem. In recent decades, treatment-resistant bacterial species, such as methicillin-resistant Staphylococcus aureus (MRSA), have become a growing source of concern for hospital workers.
Therefore, health centers have adopted strict hygiene procedures to prevent infections by dangerous microbes, which often involve washing hands with disinfectants based on isopropyl or ethyl alcohol.
A new study, published in Science Translational Medicine, reveals that a bacterium called Enterococcus faecium, resistant to multiple drugs, is becoming increasingly tolerant to the alcohols used in hand-disinfectants in hospitals. Moreover, drug-resistant E. faecium infections have increased despite the use of alcohol disinfectants, and currently represent one of the main causes of hospital-acquired infections.
This alarming development prompted a team of scientists to investigate whether E. faecium could be causing resistance to the alcohols used in hand washing. The analysis, led by experts from the University of Melbourne (Australia), took bacterial samples from two hospitals in the country for 19 years. The results suggest that E. faecium is adapting to this form of infection control, which is used in health facilities around the world.
Mitigate bacterial resistance
The experts examined 139 samples of E. faeciu , collected previously between 1997 and 2015, and analyzed the survival of each specimen when exposed to diluted isopropyl alcohol. Their findings reveal that samples collected after 2009 were, on average, more tolerant to alcohol compared to bacteria taken before 2004.
In a second phase, the authors disseminated different strains of E. faecium in the soil of the mouse cages and found that alcohol-tolerant samples colonized better in rodents that were housed in clean cages with isopropyl alcohol wipes.
The analysis of the bacterial genome revealed that the tolerant samples harbored several mutations in genes involved in the metabolism that conferred greater resistance to alcohol. The authors point out the need to examine samples in hospitals in other geographical regions before being able to draw important conclusions.
“Global efforts to mitigate bacterial resistance should consider how microbes can adapt not only to drugs, but also to alcohols and other ingredients used in disinfectants,” they concluded.