Global Trends by Martin Khor

Monday 6 June 2011

New super-bugs a threat to human life

BLURB:   The outbreak of disease caused by a new strain of E-Coli once again shows the increasing vulnerability of human beings to bacteria and viruses that are getting more deadly and more resistant to antibiotics

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The outbreak of a deadly disease caused by a new strain of the E-Coli bacteria is the latest chapter of the victory of new forms of bacteria and viruses over medicines and thus over human beings.

By last Saturday, 20 people had died and more than 1,800 were affected by a new strain of the already rare 0104 type of E-Coli.   There are other common types of E Coli which normally cause only a mild ailment.

The World Health Organization said the variant had “never been seen in an outbreak situation before.”

The centre of the outbreak is Hamburg in North Germany and almost all the deaths took place in Germany, and the others affected were either in Germany or people in 20 countries who had visited Germany.

The place of origin of the disease is still a mystery and also through what specific foods it spread.  Meanwhile, there are warnings against eating raw cucumber, tomato and lettuce, the stuff of which salads are made.

Although the “normal” E-coli usually produces mild sickness in the stomach,  the new strain of E-Coli 0104 causes bloody diarrhea and severe stomach cramps, while in over 500 of the more serious cases so far it also causes haemolytic-uraemic syndrome (HUS),  which damages blood cells and the kidneys.

A major problem is that the bacterium is resistant to antibiotics.  The treatment recommended under intensive care has been plasma exchange, kidney dialysis and blood transfusions.

Eradication of these kinds of bacteria is impractical partly because they are able to evolve so rapidly, according to Stephen Smith, a lecturer in clinical microbiology at Trinity College in Dublin, as quoted in the New York Times.

“These microbes are always exchanging information and there’s always new ones appearing,” he said. “What we’ve got now is a fusion of two different types that’s taken the worst elements of each.”  Instead, prevention is probably the best approach.

This view depicts a serious situation.  E-coli is only one example.  There are several dangerous microbes that are difficult to fight because they continuously evolve or mutate and become resistant to more and more powerful antibiotics.

One way in which they evolve is when separate genes from various strains of the bacteria, or even of different types of bacteria, come together, in a kind of hybrid.

The United Kingdom’s Health Protection Agency said the outbreak was due to a new strain of E Coli O104 with possibly a newly acquired ability to infect large numbers of people.

The BBC News quoted Professor Gad Frankel, from Imperial College London, the Sanger Institute and the Medical Research Council, as saying: "This is a new combination and a deadly combination. It has a gene which produces a toxin and another which helps the bacterium colonise the gut more efficiently, which effectively means even more toxin is produced.”

Dr 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 the most that reproduce the fastest -- bacteria and viruses that cause diseases.

Another related and worrying development is the discovery of a gene, known as NDM-1, that 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 cases in India and Pakistan and in European countries, especially among those 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, since it was found to easily jump 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 been proven to be justified.  On 7 May, 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 has been jumping among various species of bacteria at a “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, now the scientists had found NDM-1 in more than 20 different species of bacteria. “We know that NDM1 can move at an unprecedented speed making more and more species of bacteria drug-resistant,"  said Dr Mark Toleman.

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

The E Coli outbreak demonstrates the large threat this can pose to health.  Thus, antibiotic resistance and the emergence of new strains of diseases should be taken up by policy makers and international agencies like the World Health Organisation as a top-priority issue.