Superbugs resistant to alcohol can now skirt around sanitisers and disinfectants

Bacterial samples from 2009 were found to be more resistant to alcohol than those from before 2004

Multi drug-resistant 'superbugs' that can cause dangerous infections in hospitals are becoming increasingly resistant to alcohol-based hand sanitisers and disinfectants designed to hold them at bay, scientists said.

In a study of what the researchers described as a 'new wave of superbugs', the team also found specific genetic changes over 20 years in vancomycin-resistant Enterococcus, or VRE — and were able to track and show its growing resistance.

Their study was published on Wednesday in the journal Science Translational Medicine.

VRE bugs can cause urinary tract, wound and bloodstream infections that are notoriously difficult to treat, mainly because they are resistant to several classes of antibiotics.

In efforts to tackle the rise of hospital superbugs such as VRE and MRSA, or methicillin-resistant Staphylococcus aureus, institutions worldwide have adopted stringent hygiene steps — often involving hand rubs and washes that contain alcohol.

Hand sanitizer for good hygiene, drug resistance, transmission, London nurse. Reuters

Representational Image. Reuters

Tim Stinear, co-author of the study, said that in Australia alone, use of the alcohol-based hand hygiene has increased tenfold over the past 20 years.

“So we are using a lot and the environment is changing,” he said.

Yet, while rates of MRSA and other infections have stabilised due to heightened hygiene, Stinear said that VRE infection rates have not. This prompted his team to investigate the VRE bug for potential resistance to disinfectant alcohols.

They screened 139 isolated bacterial samples collected between 1997 and 2015 from two hospitals in Melbourne, Australia and studied how well each one survived when exposed to diluted isopropyl alcohol, the primary component in hand sanitisers and disinfectants.

They found that samples collected after 2009 were on average more resistant to the alcohol compared with bacteria taken from before 2004.

The scientists then spread the bacteria onto the floors of mouse cages and found that the alcohol-resistant samples were more likely to get into, and grow in the guts of the mice after the cages were cleaned with isopropyl alcohol wipes.

Paul Johnson, who co-led the study, said the findings should not prompt any dramatic change in the use of alcohol-based disinfectants.

“Alcohol-based hand rubs are international pillars of hospital infection control and remain highly effective in reducing transmission of other hospital superbugs, particularly MRSA,” he said.

Stinear said health authorities should try higher-alcohol concentrate products and renew efforts to ensure hospitals are deep cleaned and patients found to be carrying VRE infections are isolated.

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