Over the centuries, many unexpected things have come to the United States from Germany and caught on -- lager beer, sauerkraut, bratwurst and the Volkswagen Beetle are a few that come to mind -- but don't necessarily expect the novel strain of E. coli that is responsible for more than 2,800 cases of illness and 27 deaths in Germany to show up immediately in this country, advises a foodborne-disease expert in Penn State's College of Agricultural Sciences.

Because the United States imports just 2 percent of its food from Europe, and because outbreak-related export bans of fresh foods are in place, it is unlikely that the current outbreak strain of bacteria will arrive here from Germany said Edward Dudley, an assistant professor of food science at Penn State who studies the biology and evolution of pathogens that contaminate food.

"But that doesn't mean we won't see something similar at some point in time," he said. "The E. coli strain that is causing the outbreak of illness in Germany has been called a 'superbug,' but I don't like that term because it is sensationalistic. This is not something that was completely unexpected, in retrospect, and it is not accurate to say that we don't understand it."

The most notable aspect of the German outbreak is that it is caused by a new strain of E. coli that possesses genetic material and traits of two well-known pathogens, making this organism extremely pathogenic, Dudley noted.

"One is EAEC -- enteroaggregative E. coli -- which has the capabilities of sticking to the intestinal lining and producing a mucoid film that protects it," explained Dudley, who has been studying E.coli for a decade. "EAEC normally results in prolonged diarrheal illness.

"The other is Shiga toxin-producing E. coli, or STEC, which causes illness characterized by severe bloody diarrhea and can result in hemolytic uremic syndrome (HUS), a life-threatening condition that may result in the loss of kidney function."

Scientists know that E. coli, like many pathogens and nonpathogens alike, has the ability through a variety of mechanisms to move pieces of DNA to other bacteria and E. coli strains, said Dudley.

"The most likely scenario is that an EAEC strain acquired the ability to produce Shiga toxin from a STEC strain. What has occurred from an evolutionary standpoint is no surprise to those of us in this field and provides yet another example of the genetic flexibility of the bacterium that is E. coli."