New superbugs spreading from South Asia: study
"Health tourists" flocking to south Asia have carried a new class of antibiotic-resistant superbugs to Britain, researchers reported Wednesday, warning that the bacteria could spread worldwide.
Many hospital infections that were already difficult to treat have become even more impervious to drugs due to a recently discovered gene that can jump across different species of bacteria.
This so-called NDM-1 gene was first identified last year by Cardiff University's Timothy Walsh in two types of bacteria -- Klebsiella pneumoniae and Escherichia coli -- in a Swedish patient admitted to hospital in India.
Worryingly, the new NDM-1 bacteria are resistant even to carbapenems, a group of antibiotics often reserved as a last resort for emergency treatment for multi-drug resistant bugs.
Researchers said the bugs had been brought into Britain by patients who travelled to India or Pakistan for cosmetic surgery.
"If these infections were allowed to continue without appropriate treatment, then certainly one would expect to see some sort of mortality," Walsh, a microbiology professor, told BBC radio.
"It's going to be very difficult to treat the infections once the patients present with these types of bacteria. You won't get well."
In the new study, led by Walsh and Madras University's Karthikeyan Kumarasamy, researchers set out to determine how common the NDM-1 producing bacteria were in South Asia and Britain, where several cases had turned up.
Checking hospital patients with suspect symptoms, they found 44 cases -- 1.5 percent of those screened -- in Chennai, and 26 (eight percent of those screened) in Haryana, both in India.
They likewise found the superbug in Bangladesh and Pakistan, as well as 37 cases in Britain, some in patients who had recently returned from having cosmetic surgery in India or Pakistan.
"India also provides cosmetic surgery for other Europeans and Americans, and it is likely that NDM-1 will spread worldwide," said the study, published in British medical journal The Lancet.
NDM-1 was mostly found in E. coli, a common source of community-acquired urinary tract infections, and K. pneumoniae, and was impervious to all antibiotics except two, tigecycline and colistin.
In some cases, even these drugs did not beat back the infection.
"We've actually almost run out of antibiotics. We only have two left and one isn't particularly good," Walsh told the BBC.
Crucially, the NDM-1 gene was found on DNA structures, called plasmids, that can be easily copied and transferred between bacteria, giving the bug "an alarming potential to spread and diversify," the authors said.
"Unprecedented air travel and migration allow bacterial plasmids and clones to be transported rapidly between countries and continents," they said, adding that most could remain undetected.
The emergence of these new drug-resistant strains could become a serious global public health problem as the major threat shifts toward a broad class of bacteria -- including those armed with the NDM-1 gene -- known as "Gram-negative", the researchers warn.
"There are few new anti-Gram-negative antibiotics in development, and none that are effective against NDM-1," the study said.
NDM-1 stands for New Delhi metallo-beta-lactamase-1.
"We believe it's present within the community within India -- not just within the hospitals," Walsh said.
The professor said that looking ahead to what might be available to treat NDM-1, "there are no new antibiotics that are going to be available in 10 years' time".
He added: "We desperately need -- in the 21st century it sounds ridiculous that we don't have -- a globally-funded surveillance system.
"Secondly, there is a desperate need for new and novel antibiotics targeted towards these types of bacteria."
© 2010 AFP