The E. coli story is moving quickly. A news report out today suggests that sprouts might be the culprit (though it should be emphasized that the outbreak strain hasn’t been isolated from these vegetables yet):
Mr Lindemann said epidemiological studies all seemed to point to the plant nursery in Uelzen in the state of Lower Saxony, about 100km (62m) south of Hamburg – though official tests had not yet shown the presence of the bacteria there.
“Further evidence has emerged which points to a plant nursery in Uelzen as the source of the EHEC cases, or at least one of the sources,” he said.
“The nursery grows a wide variety of beansprouts from seeds imported from different countries.”
As far as the molecular analyses, Kat Holt and David Holme have been doing some additional analyses of the released genome sequences, and it looks like this is an old strain of enteroaggregative E. coli (the type which usually cause more run-of-the-mill diarrhea; free review here, but it’s a bit dated) which has simply acquired the Shiga toxin. From Kat:
It will be interesting to see what more can be found as the assemblies of the strains are improved with additional data. While the analysis so far suggests that this is a classic case of E. coli sharing genes via various mechanisms of horizontal transfer (i.e. bacteria doing what bacteria do), it will be very interesting to tease out the subtleties of the virulence genes and how they interplay to result in this particularly virulent bug.
For me, another interesting unanswered question will be the origin–if it’s on the sprouts, how did it get there? Are animals in the area carrying this? Why so many antibiotic resistance genes? Still quite a bit to learn, even if the sprouts indeed turn out to be the vehicle.