The CDC is investigating an E. coli outbreak that has sickened dozens of people in 10 states - and all signs point to romaine lettuce as the likely culprit.

The outbreak appeared to have ended last month, but not before 60 people were stricken by E. coli. Half were hospitalized. Two victims suffered kidney failure.

No product names were revealed and there's no practical advice for consumers.

The CDC reported that many of the ill ate from a salad bar at an unidentified grocery store chain that sourced its lettuce "from a single lettuce processing facility via a single distributor."

"This indicates that contamination of romaine lettuce likely occurred before the product reached grocery store Chain A locations," the investigation announcement said.

Illnesses also were reported by people who ate salad at university campuses in Minnesota and Missouri.

Ilnesses were reported in the following states: Arizona (1), Arkansas (2), Georgia (1), Illinois (9), Indiana (2), Kansas (3), Kentucky (1), Minnesota (3), Missouri (37), and Nebraska (1).

The FDA last month announced the recall of bagged romaine lettuce because of possible E. coli contamination. It was unclear whether that recall bears any relation to today's CDC announcement.