New superbugs a threat to human life

The United Kingdom's Health Protection Agency has said the outbreak was caused by a new strain of E. coli 0104 with possibly a newly acquired ability to infect large numbers of people. The BBC quoted Gad Frankel, a professor at the Imperial College London, Sanger Institute and the Medical Research Council, as having said: "This is a new combination and a deadly combination. It has a gene which produces a toxin and another which helps the bacterium colonize the gut more efficiently, which effectively means even more toxin is produced."

Mae Wan Ho, director of the Institute of Science in Society, and an expert on genetics, said this is a case of horizontal gene transfer and recombination. In this process, she said, new combinations of genetic material are created at unprecedented speed, affecting species that reproduce the fastest - bacteria and viruses that cause diseases - the most.

Another related and worrying development is the discovery of a gene, called NDM-1, which has the ability to alter bacteria and make them highly resistant to all known drugs, including the most potent antibiotics. Last year, there were reports of many such cases in India and Pakistan and in some European countries, especially among people who had visited the Indian sub-continent. At the time, only two types of bacteria were found to be hosting the NDM-1 gene - E. coli and Klebsiella pneumonia.

But it was then feared that the gene would transfer to other bacteria as well, because it was found to be jumping easily from one type of bacteria to another. If this happened, antibiotic resistance would spread rapidly, making it difficult to treat many diseases.

These concerns have proven to be justified. On May 7, The Times of India published an article based on interviews with British scientists from Cardiff University who had first reported on NDM-1's existence. The scientists found that the NDM-1 gene had been jumping among various species of bacteria at "superfast speed" and that it "has a special quality to jump between species without much of a problem".

While the gene was found only in E. coli when it was initially detected in 2006, scientists have now found NDM-1 in more than 20 different species of bacteria. "We know that NDM-1 can move at an unprecedented speed making more and more species of bacteria drug-resistant," said Mark Toleman, senior research fellow of the Cardiff University School of Medicine.

What is also worrying is that there are very few new antibiotics in the pipeline. Thus when the whole range of bacteria start developing resistance to existing drugs - and this development will be assisted by spread of the NDM-1 gene - human beings will be more at the mercy of the increasingly deadly bacteria.

The E. coli outbreak demonstrates the large threat this can pose to human health. Therefore, policymakers and international agencies such as WHO should take up antibiotic resistance and the emergence of new strains of diseases as a top-priority issue.

The author is executive director of the South Centre, a think tank of developing countries based in Geneva.

(China Daily 06/24/2011 page9)

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