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, which are getting deadlier and more resistant to antibiotics.

Recently, Chinese researchers hit international headlines by being the first to decode the human genome of the E. coli bacterium that has so far caused 37 deaths and left more than 3,000 ill. The Beijing Genomics Institute did pioneering work in analyzing the bacterium that causes this deadly disease. For instance, it found out that E. coli contains genes that make it resistant to many different antibiotics.

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. The new strain of the already rare 0104 type of E. coli is different from other common types of E. coli which normally cause only a mild ailment. The World Health Organization (WHO) said the variant had "never been seen in an outbreak situation before".

The center of the outbreak is Hamburg in northern Germany and almost all the deaths have occurred in Germany. Those 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, as is the specific food that it spread through. Warnings had been issued, though, against eating raw cucumber, tomato and lettuce, which are salad vegetables.

"Normal" E. coli usually produces mild sickness in the stomach, but the new strain of E. coli 0104 causes bloody diarrhea and severe stomach cramps. In more than 500 of the more serious cases, it has also caused 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. The New York Times quoted Stephen Smith, a lecturer in clinical microbiology at Trinity College in Dublin, Ireland, as having said that eradication of such types of bacteria is impractical partly because they are able to evolve rapidly.

"These microbes are always exchanging information and there's always new ones appearing," Smith said. "What we've got now is a fusion of two different types that's taken the worst elements of each." Prevention is probably the best approach.

Smith's 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 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)