TIANJIN, March 21 (Xinhua) -- Four newborns died and two others were still receiving medical treatment after contracting infections in a hospital in north China's Tianjin Municipality, local health official said Saturday.

    The mishap happened at the Jixian County Maternal and Child Care Service Center, where the six premature infants have developed respiratory problems since March 14, said a spokesman with the Tianjin Municipal Health Bureau.

    Four of them died after they were transferred to the Beijing Children's Hospital. The other two infants were still under treatment.

    "One of the two is in critical condition and the other takes a favorable turn," said the spokesman.

    A joint investigation team made up of experts from the Ministry of Health and the Health Department of Tianjin made an investigation on the case. Initial investigation result shows the deaths were led by hospital-acquired infection of enterobacter cloacae, a clinically significant Gram-negative bacterium.

    Another 17 premature infants at the care service center where the accident happened were not infected, the spokesman said.

    He said further investigation is underway to find out how the infection happened.