Chipotle E. coli outbreak now linked to illness in 6 states

(CNN) The E. coli outbreak linked to Chipotle restaurants has now caused 45 cases of illness across six states, according to the CDC. Sixteen of those ill individuals have been hospitalized.

The outbreak, first announced at the beginning of the month, was previously only linked to 11 restaurants in Washington state and Oregon. The CDC confirms illnesses in California, Minnesota, New York and Ohio are linked to this outbreak based on laboratory tests. Last week the agency said a case in Minnesota was not linked to this outbreak but now there are two linked cases from that state.

The first reported cases became ill on October 19 and the most recent cases began feeling sick on November 8.

The youngest patient is 2 and the oldest is 94.

All but two of the sick individuals reported eating at Chipotle within the week before becoming ill.

The source of contamination within the restaurants remains unknown, but health officials believe it is a single ingredient.

"The epidemiological evidence available at this time suggests that a common meal item or ingredient served at Chipotle Mexican Grill restaurants in several states is a likely source of this outbreak," the CDC said in written investigation update. The investigation is ongoing.

Just last week 43 locations in Washington and Oregon reopened after voluntarily closing out of an abundance of caution. Before reopening, each location replaced their food supply with all new food, sanitized each location and tested ingredients. Chipotle said, in a press release, no new cases in Washington or Oregon have occurred since then.

The chain said they are examining their entire process from farm to restaurant and expanding testing of key ingredients and examining all of their food safety procedures for any areas where improvements can be made. Chairman and co-CEO of Chipotle, Steve Ells, said in a statement the company will "leave no stone unturned."

"We are committed to taking any and all necessary actions to make sure our food is as safe as possible, and we are working diligently with the health agencies," Ells said. He also apologized to those affected and reiterated his previous statements that the well being of consumers is a priority and they take this very seriously.

Symptoms, which include diarrhea and abdominal pain, usually begin two to eight days after a person has been exposed to the bacteria and resolve within a week. Some cases are severe and patients can develop hemolytic uremic syndrome, or HUS, which is a type of kidney failure. There have been no cases of HUS or deaths from this outbreak.