An investigation into an outbreak of bacteria in four US states

The US Centers for Disease Control and Prevention said it is investigating outbreaks of E. coli bacteria in four states from an unknown food source, with reports that many of the infected people ate sandwiches from Wendy’s.
Of the 37 patients, 22 were said to have eaten Wendy’s sandwiches with romaine lettuce in Michigan, Ohio, Indiana and Pennsylvania in the week prior to their illness.
But investigators have not yet confirmed whether the romaine lettuce was the cause and also whether the vegetables used in Wendy’s were served or sold in other outlets.
The burger chain said it was taking precautions to withdraw lettuce sandwiches from its restaurants in the area. There are approximately 1,100 of the 5,940 Wendy’s restaurants in the United States in the four states.
Escherichia coli bacteria live normally in the intestines of healthy animals. Although many strains are harmless, certain types can cause severe abdominal cramps, bloody diarrhea and vomiting.