The Federal Institute for Risk Assessment (BfR) in Germany received the solitary isolate positive for S. Stourbridge.
It originated from a burger in a restaurant in the federal state of Hesse but no cases were reported in the region.
The strain will be sent to the National Reference Centre for whole genome sequencing (WGS).
This will support hypothesis generation and exposure assessment evidence on whether the meat in the burger was the vehicle of German cases.
Significant increase in Germany
The European Centre for Disease Prevention and Control (ECDC) said the investigation is being closed at EU level but routine monitoring of S. Stourbridge strains in humans will continue.
The agency added as no new cases have been reported in Germany since October, it is likely that the vehicle of infection is no longer circulating in the food chain.
An outbreak of S. Stourbridge in 2005 affected 77 people in six Member States and Switzerland. The vehicle of infection was unpasteurised goat’s cheese
Germany was the only EU/EEA Member State where there had been a statistically significant increase in cases of S. Stourbridge last year.
Fourteen cases in different federal states were notified in 2016 compared to one to five per year between 2011 and 2015.
The first case was in July and the most recent case had disease onset in late October.
Analysis suggests there was an outbreak in Lower Saxony in July and August 2016. The increase in other federal states in September and October cannot be accounted for by this outbreak.
The median age was 58 years (range: 13 to 84), 36% were male and 64% female. No cases had documented travel outside Germany before becoming ill.
Nine of 13 documented cases were hospitalised and two males died.
Other countries with S. Stourbridge cases
As of mid-December, 35 cases were reported in the EU/EEA: Austria (1), France (14), Germany (14), Ireland (1), Italy (1), Luxembourg (2), the Netherlands (1) and the UK (1).
In comparison, 11 cases were reported in 2014 and 22 in 2015.
The majority occurred between April and October. The latest dates of onset were in October in Luxembourg in two siblings, aged one and two, who had visited Germany before falling ill.
Twelve cases were hospitalised: nine in Germany and one each in Austria, Luxembourg and the UK.
The Robert Koch Institute compared German whole genome sequences and those provided by France, Ireland and Luxembourg over a 12 year period.
They were very closely related which may suggest a single or small number of persistent primary sources resulting in intermittent human infection.
ECDC said there was a ‘striking’ difference in the age distribution between the cases in Germany (median 58 years, ranging from 13 to 84) and France (median 53, ranging from 0 to 80) compared with other countries (median one year, ranging from 0 to 10).
This may be due to a difference in exposure, added the agency.
Meanwhile, the Public Health Agency of Canada (PHAC) is investigating an outbreak which has sickened two more people, bringing the total to 14.
The source of the E. coli O121 infection is still unknown and five people were hospitalised.
Cases have been reported in British Columbia (5), Saskatchewan (4) and Newfoundland and Labrador (5) with illness onset dates from November 2016 to January 2017.