A baby boy born 16 weeks premature has become the third infant to die after receiving an intravenous infusion tainted with bacteria at the University Clinic in the western German city of Mainz.

The hospital says the baby was one of 11 young children in its pediatric intensive care unit to be given the routine infusion on Friday. Two other infants died Saturday.

Hospital officials said other infected children were responding well to the antibiotics and their health continued to improve Tuesday.

The clinic believes the drip solution became infected while being mixed at the hospital. Prosecutors have launched an investigation into involuntary manslaughter and bodily injury, but have so far failed to identify suspects.