The killer Indian superbug menacing Australia
A once-harmless bacteria from an Indian community has evolved, spread across the globe and become a killer superbug now threatening Australian hospital patients.
By tracing the origins of a drug-resistant strain of golden staph, Melbourne researchers have shed new light on how superbugs emerge as well as measures needed to protect patients.
The Doherty Institute genetic investigation also serves as a warning of how rampant antibiotic use in countries such as India present a very real danger to Australian and other patients around the world.
More than 5000 Australians have suffered staphylococcus aureus - or golden staph - infections in their bloodstream, which are fatal in about one in four cases.
By uncovering the origins of the "Bengal Bay clone" strain of the bacteria, lead researcher Associate Professor Steven Tong said Australian hospitals could better isolate patients who had visited India in their past to provide them more appropriate drugs and stop the bug's spread.
"We found this strain or clone of golden staph we have shown originated on the India subcontinent and, while on the Indian subcontinent from 1960 through to the 1990s, it gradually acquired more and more resistance to the antibodies that get used - until it gets to the point it can be called a superbug, where it is entirely drug-resistant," he said.
"Then we saw instances where it got exported from India as people travelled out to England, The Netherlands or Australia these people bring the drug-resistant bug with them and it is hard to treat and causes severe disease."
Examining the complete DNA sequence from 340 samples from 14 countries, the Doherty team was able to track the bacteria's mutations from generation to generation, building up a genetic family tree across the globe and decades.
Results published in the journal mBio revealed how the Bengal Bay clone caused small-scale community outbreaks before progressively acquiring antibiotic resistance and global transmission.
"At a global level, people are just doling out antibiotics in places like India and that is generating this resistance that is impacting on people all around the world," Prof Tong said. "This is not just an Indian problem, it is a world problem so we need to start thinking how to help them out."