After injecting poop bacteria into brain cancer patients' brains, doctors forced to resign

Enterobacter aerogenes.

Two neurosurgeons at UC Davis have resigned after infecting brain cancer patients with a pathogenic bacteria from their bowels in a last-ditch effort to halt progression of their cancers. The three patients gave their consent to Dr. J. Paul Muizelaar, 66, the former head of the neurosurgery department, and his colleague, Dr. Rudolph J. Schrot. But the doctors hadn't received OKs from the FDA, or school authorities, and the procedure hadn't even been tested on animals. It's a complicated story that strikes at the heart of medical experimentation ethics, and how difficult treatment options are for patients with aggressive cancers.
All three of the glioblastoma patients died. It's difficult to know what role the experimental treatment played in their deaths, because generally those diagnosed with this highly malignant form of cancer have short survival prognosis. Median survival is under 15 months.

Snip from the Sacramento Bee's coverage:

Muizelaar and Schrot called their novel approach "probiotic intracranial therapy," or the introduction of live bowel bacteria, Enterobacter aerogenes, directly into their patients' brains or bone flaps. The doctors theorized that an infection might stimulate the patients' immune systems and prolong their lives. The first patient lived about 5 1/2 weeks. The second survived another year, an outcome that buoyed the doctors and seemed to bolster their theory, they said.
The institutional trouble began in March 2011, when a newly diagnosed third patient developed sepsis, became unresponsive and died two weeks after being deliberately infected. The university's first internal investigation soon followed.

The Sac Bee has been covering this story for years, and you can dig in to their investigative reporting here.
University investigators say Muizelaar and Schrot “deliberately circumvented” internal policies at UC Davis, “defied directives” from top leaders, and evaded federal regulations designed to protect patients' rights.
Nature has a roundup of the science, here.