Two more Ohio cases -- one each in Lucas and Seneca counties -- also match the eight that have been linked here, said Ohio Department of Health spokesman Kristopher Weiss. Nine cases in Michigan, where case reports have risen this month and officials have said they suspect ground beef, are matches, said Dr. Mysheika LeMaile-Williams, Columbus Public Health's medical director and assistant health commissioner.
Investigators have yet to find a source of the bacterial infections, which have sickened people of all ages and led to several hospitalizations. Health officials from the state, Columbus and Delaware, Fairfield and Franklin counties are collaborating on the central Ohio investigation.
Michigan and Ohio authorities are working with the federal Centers for Disease Control and Prevention now that the outbreak has spread.
In the effort to nail down a culprit, the Franklin County Board of Health collected a food sample from someone who had an E. coli infection and sent it to the Ohio Department of Agriculture for testing.
Health Commissioner Susan Tilgner declined to say what type of food it was.
"We don't want to implicate a food that doesn't need to be implicated," Tilgner said. "It may not be related to the outbreak at all, but we're certainly not going to leave that stone unturned."
Lab results might be available as soon as today.
Many of those sickened with the bacteria have eaten ground beef and fresh fruits and vegetables, according to Columbus Public Health. The department did not say where those products were purchased or consumed.
Past outbreaks have been linked to ground beef, pepperoni and other processed meats, spinach, sprouts and lettuce.
Water, which can be a source of E. coli infection, has been ruled out because there doesn't appear to be any links to a water park or other recreational area, LeMaile-Williams said.
"Now, what we are really looking at are foods," she said.
No cases of transmission within families have been documented, but health officials have heard of infections spreading that way, which reinforces the importance of diligent hand washing and careful food preparation, LeMaile-Williams said.
People with E. coli O157:H7 typically have diarrhea, which can be bloody and severe, and abdominal cramps two to eight days after infection. People with these symptoms should see their physicians.