2 cases of Legionnaires' possibly linked to University of Chicago Hospital

CHICAGO (WLS) -- For the second time in a week, state health officials said Chicago hospital patients had been diagnosed with Legionnaires' disease.

The Illinois Department of Public Health has identified two new cases of the potentially-deadly lung infection, which is contracted by inhaling aerosolized water containing the Legionella bacteria.

Both infected individuals were recent patients at the University of Chicago Medical Center, but it's unclear if they contracted the illness at the Hyde Park hospital. UC officials said extensive water system testing found no evidence of Legionella at the facility. IDPH has not determined the source of the infection.

IDPH said the infected patients had also received treatment during the potential exposure period at other medical facilities but declined to identify those locations.

On April 26, IDPH said two different patients at another south side medical center, Mercy Hospital, had also been diagnosed with Legionnaires' disease. Water testing at Mercy came back positive for Legionella, officials said. The facility has since flushed its water system.

University of Chicago Medical Center statement:

"Two patients recently treated at the University of Chicago Medical Center have been identified as having been infected with Legionella. The University of Chicago Medical Center has a comprehensive water management program that follows the highest federal standards. Testing of hospital water has shown no evidence of Legionella growth. We are confident all our patients are safe.

We take Legionella and its potential health concerns seriously and are working with state and local health authorities, as their investigation continues to find the exact source of the bacteria inside or outside our health system. To be clear, these patients were in our facilities for only a portion of their risk period, and none of our water tests has revealed Legionella. We do not have any information about water testing at other sites these patients may have visited during the risk period."