A 83-year-old woman from the Diepholz area in Lower Saxony who had been hospitalised with bloody diarrhoea since May 15 died last Saturday, the state Health Ministry confirmed on Tuesday.
A second woman older than 80 infected with the EHEC bacteria died on Sunday in the Schleswig Holstein area of Stormarn, but she was also being operated on for something else, local health authorities said.
And Bremen authorities confirmed that a 24-year-old woman died on Monday night after suffering typical EHEC symptoms. Laboratory work is currently being carried out to see what her infection actually was.
More than 350 cases or suspected cases have been registered, with several of those affected in critical condition. One patient is in a coma. EHEC can lead to kidney failure which can be fatal, as well as severe anaemia.
Two company canteens run by consultancy giant PriceWaterhouseCoopers in Frankfurt were closed on Friday after it was established that all 19 people infected with the EHEC bacteria had eaten there.
Oswalt Bellinger from the Frankfurt Health Authority said deliveries of food were being examined.
"We reckon that the source of infection is in north Germany," he said.
"And we still think that the transmission took place via raw foods." Results from laboratory tests were to be expected by the end of the week.
The EHEC bug occurs sporadically every year in Germany, but the current outbreak is unusual, according to public health body, the Robert Koch Institute (RKI).
The cases are occurring mostly in northern Germany but there are also preliminary notices of infection from southern and eastern Germany, it said.
Hotspots of infection include the northern state of Schleswig-Holstein, where the number of suspected cases rose between Monday and Tuesday from 90 to 200, as well as Lower Saxony, Hamburg, Hesse and Mecklenburg-Western Pomerania.
“The number of severe cases (more than 80 HUS cases) in a short time-frame is very unusual – and the age groups are atypical. Currently, adults, overwhelmingly women, are affected,” an RKI statement said.
It said that last year around 1,000 EHEC cases were reported in Germany, resulting in two deaths.
People can reduce their risk of infection by cooking their food thoroughly, as well as observing general food hygiene rules.
Those with diarrhoea should be strict about washing their hands and avoiding contact with children and those with weakened immune systems. People with bloody diarrhoea should go to a doctor immediately.
The RKI has sent a team to Hamburg, where so far the most infections have been registered, to help the health authorities there in the hunt for a source of the infection.