Hospital superbug increasingly resistant to handwash disinfectants, study finds
Bacterial strains resistant to alcohol-based sanitisers represent a ‘new wave of emerging superbugs’, it is claimed.
Handwash sanitisers commonly used in hospitals are becoming increasingly ineffective against a notorious superbug, research has shown.
Scientists in Australia made the discovery after testing bacterial samples collected over a period of 19 years.
They found strong evidence that the superbug vancomycin-resistant enterococcus (VRE) is growing increasingly immune to alcohol-based disinfectants.
VRE infections are some of the most difficult to treat because the bacteria are resistant to many classes of antibiotic, including the “last resort” drug vancomycin.
To combat dangerous microbes, hospitals in the UK and around the world have adopted strict hand-hygiene procedures.
These generally involve hand rubs or washes containing ethyl or isopropyl alcohol disinfectants.
The Australian team screened 139 Enterococcus samples collected from two hospitals between 1997 and 2015 to see how well the bugs survived when exposed to diluted isopropyl alcohol.
Those obtained after 2009 were found to be more tolerant to the disinfectant than those sampled before 2004.
In another part of the study, bacteria were seeded on the floors of laboratory mouse cages.
Alcohol-tolerant microbes were better able to colonise the guts of mice after the cages were cleaned with disinfectant wipes.
Professor Paul Johnson, a member of the team from Australian health service provider Austin Health, said: “Alcohol-based hand rubs are international pillars of hospital infection control and remain highly effective in reducing transmission of other hospital superbugs, particularly methicillin resistant Staphylococcus aureus (MRSA).”
The researchers traced the increased resistance to alcohol-based disinfectants to several Enterococcus mutations in genes that play a role in metabolism.
Lead scientist Professor Tim Stinear, from the Doherty Institute in Melbourne, described the sanitiser-resistant VRE strains as “a new wave of emerging superbugs”.
He added: “Alcohol-based hand hygiene use has increased tenfold over the past 20 years in Australian
hospitals, so we are using a lot and the environment is changing.”
Writing in the journal Science Translational Medicine, the team said efforts to combat superbugs should focus on how bacteria become resistant to disinfectants as well as antibiotics.