The DuPage County Health Department closed a Lombard restaurant in connection with the investigation into four confirmed cases of E. coli in people admitted to a county hospital this week, officials said today.

Jason Gerwig, a public information officer for the DuPage County Health Department, said his agency is looking at a Lombard restaurant as a possible source for the outbreak, and said the restaurant had been temporarily closed at 5 p.m. Friday as part of the investigation. He did not want to name the restaurant until he had received further confirmation that the four people with confirmed cases of E. coli had been there, he said.

Gerwig said the total number of cases confirmed or under investigation is about 10.

He said that it is “unusual” to have a cluster of cases like this, “which is why we are investigating.”

The four confirmed cases were all hospitalized at Advocate Good Samaritan Hospital in Downers Grove, officials said Friday.

Melaney Arnold, a spokeswoman for the Illinois Department of Public Health, said her agency had confirmed that those four individuals had contracted the same strain of E. coli and that the agency is continuing to study other, related reports of E. coli in that area. She could not confirm how many other cases were involved or if the lab testing will be done this weekend or Monday.