Early tests on about 10 close associates of the 26-year-old Chicago pediatric resident that tested positive for tuberculosis have come back negative, the Chicago Tribune reported Tuesday. They include relatives, friends and hospital colleagues.

Dr. Susan Gerber, chief medical officer at the Chicago Department of Public Health, told the newspaper the lack of infection suggests the bacterial disease probably had not spread. Hospital officials previously warned that hundreds of patients that came in contact with the resident could be infected.

Patients at Northwestern Memorial Hospital, Prentice Women's Hospital, Children's Memorial Hospital and Evanston Hospital were exposed to TB between November of last year and April of this year.

The pediatric resident was in Northwestern's training program and had rotated through the other three hospitals.

At Children's Memorial alone, it is estimated that approximately 150 children and 300 employees were exposed.

Northwestern says it's contacting 17 patients who may have been affected and is evaluating another 100 who may have received care from the worker.

The Associated Press contributed to this story.

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