Initial tests negative for outbreak E coli in German sprouts

Jun 6, 2011 (CIDRAP News) – German authorities investigating a possible sprout link to a large Escherichia coli outbreak said today that lab samples are negative so far, dashing hopes for a quick end to the investigation and adding more confusion to the search for the source.

Yesterday officials in Germany's Lower Saxony state said at a press conference that they found clear signs that sprouts produced by an organic farm in the northern part of the country were responsible for the illnesses, but today the area's agriculture ministry said 23 of 40 samples taken from the facility have tested negative for the outbreak strain, the UK-based Guardian newspaper reported today. Testing is still under way on 17 more samples.

In a statement today, Germany's health ministry said the negative tests don't exclude sprouts as a source, and it warned consumers not to expect a quick identification of the outbreak source, the Guardian reported.

The outbreak strain, E coli O104:H4, has so far been linked to 1,672 enterohemorrhagic infections and 661 cases of hemolytic uremic syndrome (HUS), a severe and potentially fatal kidney complication, according to the latest update today from the European Centre for Disease Prevention and Control (ECDC). The number of fatalities stands at 22.

The World Health Organization (WHO) said in its updated background information today that the outbreak cases have been reported from 12 countries, and all but one patient lived in or traveled to Germany. In one case, an individual got sick after having contact with an infected visitor from northern Germany.

Michael Osterholm, PhD, MPH, director of the University of Minnesota's Center for Infectious Disease Research and Policy, publisher of CIDRAP News, said that complicating the message about the possible sprout threat by releasing partial testing results, especially after a round of earlier testing miscues with Spanish cucumbers, signals "borderline incompetence" among those leading Germany's outbreak investigation.

He said response to the outbreak so far undermines confidence in health officials, a problem that extends beyond German borders to the global public health community. Osterholm said it's critical that investigators on the scene stick with an epidemiologic focus to not only look carefully at what both cases (people who got sick) and controls (healthy people) consumed, but also to conduct trace-back investigations on the products both groups consumed.

"That's how you end up discerning which products are involved, especially if multiple products have been implicated," he said.

The investigation would also benefit from more specifics about illness onsets in order to help determine if the outbreak is ongoing or starting to taper off, Osterholm said. He added that it's unclear how German health officials are calculating illness-onset dates. A longer illness onset date has been highlighted as an unusual feature in the outbreak, but Osterholm said more information is needed to determine of they're referring to the onset of diarrhea illness or HUS, which when it occurs typically begins 12 to 15 days after the start of diarrhea symptoms.

Daniel Bahr, Germany's health minister, along with other health officials said hospitals in Hamburg are having a difficult time managing the surge of patients with E coli infections, according the Guardian report.

In other developments, European Union (EU) health ministers met today to discuss the latest health developments with the outbreak, and the EU's agriculture ministers will meet tomorrow to discuss food safety and economic impacts of the event, according to an EU statement. Because Spanish cucumbers were wrongly implicated in the outbreak and health warnings for other produce items have tamped down fresh vegetable sales, the ministers will discuss how to compensate producers for big losses.

Last week the US Food and Drug Administration (FDA) said it imports little fresh produce from the EU and that it has stepped up surveillance on shipments of suspected vegetables. Today, Sebastian Cianci, spokesman for the FDA, told CIDRAP News that the increased surveillance also applies to all sprouts and sprout seeds from Germany and Spain. He added that the United States hasn't received any shipments of sprouts or sprout seeds from those two countries since at least October.

See also:

Jun 6 Guardian report

Jun 6 ECDC update

Jun 6 WHO background information

Jun 5 CIDRAP News story "Sprouts linked to European E coli outbreak"

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