The child was prematurely born after the twenty-fourth week of pregnancy and had been among the five babies in critical condition after receiving the contaminated feeding drips at the weekend.
It died on Monday evening at the University Medical Centre of the Johannes Gutenberg University.
“This child was among the five children who were in a critical state,” head of the hospital Norbert Pfeiffer said. “Due to its extremely premature birth, we had to expect the worst, which has unfortunately come to pass.”
Eleven babies in the intensive care unit were exposed to the intestinal bacteria through feeding drips there, and two died over the weekend. Doctors had warned on Monday afternoon that they did not expect the third infant to survive.
Mainz senior public prosecutor Klaus-Peter Mieth said on Monday the deadly infections were likely caused by dirty tubing used for feeding the babies.
“The tubes are the only place on the machines that the workers touch directly and could therefore add bacteria,” Mieth said.
His office is now investigating on suspicion of negligent manslaughter and negligent bodily harm in the case.
The clinic, however, believes it may be possible the bacteria found its way into the infusions in the hospital pharmacy.
On Tuesday the public prosecutor's office expects the results of microbiological testing to find out at which point during preparation the bacteria could have entered the infusions.