As the death toll in Germany's E coli outbreak rose to 18 and the number of infections climbed to more than 1,830, health authorities are investigating the possibility that the killer bacteria may have spread from a restaurant in Luebeck, near Hamburg, where some of the sickened people dined last month.

A local newspaper in Luebeck reported that 17 people became infected with the bacteria after visiting the restaurant in the Hanseatic port city between May 12 and 14. Among them were eight women in a group of tourists from Denmark and eight women from different parts of Germany who took part in a seminar. One of them died of infection caused by the Escherichia coli bacteria while two others and a child from southern Germany, who ate in the restaurant, are in critical condition, the newspaper said.

Specialists of the Robert Koch Institute (RKI), Germany's national disease prevention and control centre and the Federal Institute for Risk Evaluation searched the restaurant on Saturday and they are now investigating its supply chains to look for clues on how the deadly bacteria came into circulation. The owner of the restaurant told ZDF TV network that he received his supplies of fresh vegetables from Hamburg's vegetable wholesale market where cucumbers imported from Spain were initially suspected as the prime source of the epidemic three weeks ago, prompting Hamburg state authorities to ban their imports.

However, investigations later showed that even though the Spanish cucumbers carried the E coli bacteria, they were not the highly virulent strain which causes the lethal infection. The RKI dismissed speculation that the birthday party of the Hamburg port at the beginning of last month, which was attended by more than 1.5 million people, could have contributed to the rapid spreading of the Enterohaemorrhagic E coli bacteria.

The area in and around Hamburg has been the epicentre of the epidemic and most of 17 casualties in this country and the largest number of infections are in northern Germany. Most of around 70 infected people in eleven European countries have either visited Germany shortly or came in contract with those returned from this country. The first only casualty outside Germany so far was a Danish woman who died shortly after returning from a visit to this country.

Meanwhile, scientists who deciphered the genetic code of the killer bacteria have discovered that it is a cross between an extremely dangerous strain from central Africa and a hitherto unknown strain in Europe.

Scientists said through genetic transfer, the new strain has acquired the capability not only to produce deadly toxins in large quantities, but also to colonise the bowel more effectively. The new strain is also reported to be resistant against several medicines, including some antibiotics.

Even though it is not uncommon for bacteria to evolve and swap genes, scientists are baffled how the African and European strains came together to produce the most aggressive E coli bacteria ever surfaced. It can cause the potentially deadly haemolytic uraemic syndrome (HUS), which results in acute kidney failures, seizures, strokes and coma. More than 520 patients have been diagnosed with HUS symptoms all over Germany.

Blood transfusion is the most common treatment in severe HUS cases and German clinics and health authorities in northern Germany have been appealing for blood donations as the blood banks in several cities were running out of their reserves.

Germany's health authorities continued to recommend avoid eating tomatoes, cucumber and lettuce as they are still unable to pinpoint the cause of the infection even three weeks after its outbreak. The European Commission yesterday offered to cooperate more closely with German authorities in identifying the source of the infection. EU’s Health Commissioner John Dalli said in in Brussels that the commission is ready to send a team of experts to Germany to assist the German authorities in dealing with the crisis.

The commission has been in regular contact with the German authorities on the E coli outbreak and its impact on public health and this will be high on the agenda of a meeting of EU health ministers in Luxembourg on Monday, Dalli said in a statement. The commission will also set up an E Coli web site on Monday to facilitate speedy and more efficient exchange of information among health officials and researchers on their efforts to deal with the crisis in their areas.

The web site will for the first time publish English translations of the RKI's findings and treatment methods advocated by the institute for the benefit of other EU nations facing the threat of an epidemic.