Four Massachusetts hospitals failed to do enough to make sure doctors were free of infectious diseases before allowing them to practice medicine, federal investigators concluded after unraveling the case of a junior physician stricken with tuberculosis, The Boston Globe reports.

An OSHA investigation found that Boston Medical Center, the principal assignment of the surgical resident, didn't follow up after suspicions emerged about her health. And OSHA concluded that three other hospitals where the doctor rotated didn't have mechanisms for gathering detailed information on the health of trainee doctors before allowing them to begin rotations.

OSHA in August and September issued the hospitals ''letters of significant finding," which The Globe obtained through the federal Freedom of Information Act. No citations or fines were issued. The federal agency has no guidelines specifically covering tuberculosis in the workplace.

The doctor treated patients and had contact with other healthcare workers for six months even though she had an infectious form of TB. The case came to light in June, just days after the physician was suspended from treating patients at Boston Medical.

The OSHA investigation found that in the summer of 2004, the doctor tested positive for tuberculosis before starting her job at Boston Medical and was referred to a city clinic for a chest X-ray and other exams. She skipped that appointment, but continued to provide care at Boston Medical and rotated through three other medical centers: Brockton Hospital, Cape Cod Hospital, and the VA Boston Healthcare System.

Disease trackers have said they believe the woman was infectious from December 2004 through June.

As a result, nearly 5,600 patients and healthcare workers underwent tuberculosis screening tests. Investigations by disease detectives found that four patients and 13 healthcare workers who tested positive for TB were probably exposed to the bacterial illness by the doctor, said Dr. Anita Barry, chief disease tracker at the Boston Public Health Commission.

None of the patients or medical personnel have shown symptoms of the disease, meaning they're not currently capable of spreading it. A small percentage of people with latent TB eventually become infectious. To eliminate all traces of the disease, patients can take a nine-month course of drugs, and the 17 people apparently exposed by the doctor were offered the medication, Barry said.

The physician's name has never been publicly disclosed; hospital and public health authorities say federal patient privacy laws prevent them from identifying her. The fate of the doctor remains unclear. A Boston Medical spokeswoman declined to provide any information about the physician, including whether she has returned to the staff.

As a result of the case involving the doctor, all four hospitals said they adopted measures designed to prevent a repeat episode and to better ensure the safety of patients and healthcare workers, The Globe reports.