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I’ve been following the developing story of NDM-1, an enzyme that confers antibiotic resistance to gram-negative bacteria, since before the first article on its appearance was published in The Lancet Infectious Diseases in August last year (see F1000 evaluations). At the time, many of the cases of infection in India – but not all – were linked to hospital visits, and most cases seen in the UK were in people who’d been hospitalised in India or Pakistan.

It’s the ‘but not all’ that is most worrying here.

A recent paper by the same study group, evaluated twice in F1000 by Will Stubbings and by Andrea Endimiani and Robert Bonomo,  has found isolates with NDM-1 in both waste and drinking water samples in New Delhi. If this weren’t cause enough for concern, the blaNDM-1 gene was present in numerous gram-negative pathogens that had not previously been described as NDM-1 carriers.

Most bacteria with NDM-1 were highly-resistant to other antibiotics besides those destroyed by NDM-1 itself, but that’s not all, in the very measured words of evaluator Will Stubbings, “in the laboratory the transfer of the NDM-1 gene between bacteria in some case was more efficient at temperatures around 30ºC, suggesting that the environmental conditions in India may be conducive to the transfer of NDM-1″.

“India is one of the great economic successes of the early 21st century, and sophisticated medicine is increasingly available,” commented Dr David Livermore, Director of the UK’s Antibiotic Resistance Monitoring & Reference Laboratory at the Health Protection Agency, who is a co-author of both papers, “but the problem is that India’s hospitals – however good – source their patients, staff and food from a milieu where highly resistant bacteria and their genes are circulating, and where antibiotic use is weakly controlled.   It is a dangerous mixture.”