Four hospital outbreaks of drug-resistant tuberculosis were reported by the federal Centers for Disease Control.

The highly infectious respiratory disease apparently spread among AIDS-infected patients and was transmitted to some health care workers, the CDC said Thursday.The outbreaks occurred in one hospital in Miami and three in New York City and involved a total of 187 patients, most of whom were infected with the human immunodeficiency virus, or HIV, that causes AIDS. But eight cases of TB also were reported among health-care workers in those hospitals, the CDC said.

Skin tests indicated 19 others had been exposed to the TB bacterium.

Patients with HIV-weakened immune systems are at high risk of contracting other life-threatening infections, including TB. In one hospital, of 29 patients who came down with TB, 21 died an average of seven weeks after diagnosis. The three other hospitals also reported high fatality rates of patients within weeks of TB diagnosis.

The CDC warned that this TB microbe, which resists drugs normally used against the disease, may also have spread into the community.

"I would term it a serious problem," said Dr. Samuel Dooley, a CDC epidemiologist. "What is unusual is to see large clusters of cases like that."

The CDC circulated a report on the outbreaks to alert health care workers that the disease can be transmitted in medical facilities. He urged them to maintain infection control procedures to prevent transmission of TB.