Sydney, Oct 24 : Australian research has identified a common antibiotic that is driving the rise of an almost untreatable superbug.

In a study published on Thursday, international researchers led by the University of Melbourne, Peter Doherty Institute for Infection and Immunity, and Austin Health found that an antibiotic commonly prescribed for liver disease patients could expose them to a greater risk of a dangerous superbug, Xinhua news agency reported.

Superbug is the name given to bacteria, viruses, parasites, or fungi that have developed a resistance to one or more of the antibiotics used to treat them, also known as antimicrobial resistance (AMR).

The World Health Organization has identified AMR as a top global public health and development threat, estimating it contributed to 4.95 million deaths globally in 2019.

The new eight-year study found that the antibiotic rifaximin has led to the global emergence of an almost untreatable form of the AMR superbug vancomycin-resistant enterococcus faecium (VRE), a contagious bacterial infection that can cause severe reactions in hospitalised patients.

Laboratory experimentation and clinical studies undertaken by the researchers found that rifaximin use has caused changes in the DNA of VRE, making it resistant to daptomycin, a major last-resort antibiotic used to treat multidrug-resistant pathogens.

Glen Carter, senior author of the study from the University of Melbourne and the Doherty Institute, said the study challenges the previously-held belief that rifaximin is low-risk for causing AMR.

"We've shown that rifaximin makes VRE resistant to daptomycin in a way that has not been seen before," he said.

"It is also of concern that these daptomycin-resistant VRE might be transmitted to other patients in the hospital; a hypothesis that we are presently investigating."

The researchers said the findings highlight the critical need for effective genomics-based surveillance to detect emerging AMR.

/IANS