The bacteria, though, were not approved for use in humans and had been purchased for the doctors' study involving lab rats, according to university and federal documents.
Only after the third patient was treated in March 2011 — and died 14 days later of sepsis, a severe bodily reaction to infection — did the university order the neurosurgeons to "cease and desist," The Bee said.
Both Muizelaar and Schrot still have their positions at the medical center, though Muizelaar recently took a leave of absence from clinical work, The Bee said.
Attempts by The Associated Press to reach Muizelaar and Schrot for comment were unsuccessful.
University officials have rejected the findings of the report and say patient care at the medical center remains "excellent."
Medical center officials did not immediately provide comment to The Associated Press about the report.
Information from: The Sacramento Bee, http://www.sacbee.com