The death toll from a killer E. coli outbreak centred in Germany has risen to 50 with another death in Germany and one in the United States, health authorities said Thursday.

A 74-year-old woman died in Germany's northern Hanover region on Wednesday from haemolytic uraemic syndrome (HUS), a kidney complaint caused by the enterohaemorrhagic E. coli (EHEC) bacterium, local health official Nils Meyer said.

The (WHO), meanwhile, confirmed that a person who died of HUS in the United States had been infected with the same strain of EHEC.

All but two of the EHEC fatalities have so far been in Germany, apart from the new US case and a woman who died in Sweden shortly after returning from a a visit to Germany.

The WHO said 4,050 infections have been confirmed in 14 European countries, the United States and Canada -- more than 3,900 of them in Germany.

The outbreak has been blamed on organic vegetable sprouts.