Indian doctors warned earlier this year about the threat from a new multi-drug resistant "superbug" -- months before a British study that New Delhi has condemned for scaremongering.
A team of researchers from a leading private hospital in Mumbai came to similar conclusions as the British study, which warned that foreigners coming to India for cut-price treatment could pick up NDM-1 and spread it worldwide.
India's health ministry angrily dismissed the claim in the medical journal The Lancet as exaggerated and unfair, while some politicians saw it as a conspiracy designed to scupper the country's booming health tourism industry.
But Indian researchers themselves had said in March that they found 22 incidences of "New Delhi metallo-lactamase-1" producing bacteria in 24 infection cases between August and November last year.
"This high number in a relatively short span is a worrisome trend," the team from the Hinduja hospital said in the Journal of the Association of Physicians of India.
Equally worrying is the fact that NDM-1-carrying bacteria are resistant even to carbapenems, a group of antibiotics often reserved as a last resort for emergency treatment for multi-drug resistant bugs.
"The growing incidence and also the diversity of carbapenemase-producing strains is therefore of major concern," the researchers added, warning that the superbug "has the potential for further dissemination in the community".
The Indian team said they did not know the exact prevalence of NDM-1 but added that its spread "may endanger patients undergoing major treatment at centres in India and this may have adverse implications for medical tourism".
An Australian infectious diseases specialist on Friday said three people who had travelled to India for treatment had contracted the infection and the cases could be just the "tip of the iceberg", amid concern about its global spread.
Dr K. Abdul Gharfur, a consultant on infectious diseases in the southern city of Chennai, has said that the Indian medical authorities are in denial about the extent of multi-drug resistant infections.
He told AFP on Friday that no country was immune to the problem but it was likely to be more acute in places like India because of a lack of effective controls on the prescription of antibiotics.
"This bacteria, NDM-1, is increasing. It's true it's spreading in India. I'm sure it exists in almost every major hospital in India. But we have limited data," he said.
Few hospitals, including in the private sector, have specialist infection control departments and there was a general lack of awareness among doctors about the spread of drug-resistant infections, he added.
"The responsible authorities should only allow the use of antibiotics by qualified people" and proper monitoring of infections be carried out, as antibiotic-resistant infections are increasing, he said.
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