(See Correction & Amplification below.)

FRANKFURT—Europe's severe outbreak of Escherichia coli bacterial infections worsened further as more people succumbed to the lethal strain in Germany and around Europe.

Total reported cases in Germany reached 1,733, with 520 of those resulting in severe complications that can lead to kidney failure, according to the Robert Koch Institute, a research body funded by the German Health Ministry. Cases have been reported in at least 11 other European countries.

Meanwhile, there were four suspected cases in the U.S., said Chris Braden, the U.S. Centers for Disease Control and Prevention's director of food-borne, waterborne and environmental diseases. He said all the cases involved people who had recently traveled to Germany.

The Spanish, Portuguese and German governments said on Friday that they would request EU aid for farmers affected by the outbreak, which is costing farmers millions of euros as mountains of vegetables sit rotting and uneaten.