For the first time, state investigators have linked the death of a patient to the case of a former nurse who secretly stole narcotics from St. Cloud Hospital in 2010 and 2011.

Six people required intensive medical care, and one died, after contracting a rare bacterial infection from IV bags that were contaminated during the drug thefts, the Minnesota Department of Health said in a report released Tuesday.

The former nurse, Blake Zenner, 42, of Kimball, Minn., pleaded guilty last month to stealing narcotic painkillers from at least 23 patients and replacing the missing drugs in their IV bags with salt water. Zenner, who had worked at the hospital for 17 years, surrendered his nursing license and awaits sentencing.

The Health Department stopped short of saying that the infection was to blame for the patient's death, but said it was "highly unlikely" that it was just a coincidence.

Hospital officials, however, disputed the report.

"We respectfully disagree with the health department's assertion that a death occurred as a result of the drug diversion," said Jeanine Nistler, a hospital spokeswoman, in a written statement. She said the patient who died had tested positive for a bloodstream infection when admitted to the hospital, and quickly deteriorated.

The case made headlines in early 2011, when officials disclosed that two dozen patients had been infected by rare bacteria after a nurse tampered with their medications. It was one of a series of painkiller thefts that alarmed state officials and led to the creation of a special task force of health care and law enforcement officials early this year. Their review found that the number of painkiller thefts reported at Minnesota hospitals and nursing homes more than doubled between 2005 and 2011.

But Tuesday's report is the first detailed accounting of what happened to the St. Cloud patients, who have never been publicly identified.

Hospital officials became suspicious in February 2011, when they first discovered the unusual infections in several patients. They called in state and federal health investigators, who eventually found more cases and traced them to Zenner, who admitted tampering with the narcotic supplies.

In all, the report found that 25 patients, who ranged in age from 35 to 84, developed the unusual infections, with symptoms including vomiting, chills, nausea, fever and pain.

48 hours

Dr. Aaron DeVries, who led the state investigation, said six patients ended up in intensive care, including the one who died, and that three needed unexpected surgery.

DeVries said it's difficult to pinpoint what caused the setbacks, because the patients were already sick. But "what we can say is that these things happened within the 48 hours following the positive blood culture," he said.

At the same time, the report said the investigation may have underestimated the impact on patients. "It is possible that other case patients, whose pain medications were likely diverted and contaminated, also suffered undue, unnecessary harm," the report said.

Nistler, the hospital spokeswoman, said that lawyers for nine of the patients have contacted the hospital, but that no lawsuits have been filed.

"It has never been our intention to minimize the drug diversion's impact on patients," she said. "We have acknowledged from the beginning that the diversion caused patients to experience unnecessary pain and additional treatment. However, we cannot unequivocally say that returns to surgery and transfers to the ICU were related to the diversion."

Zenner's lawyer, Paul Engh, declined to comment on the report. Under a September plea agreement, Zenner faces a maximum penalty of four years in federal prison.

A spokeswoman for the U.S. Attorney's office, which handled the case, said that "the court will consider all the facts of the case when it comes to Zenner's sentencing."

Dr. Ed Ehlinger, the state health commissioner, called it a "tragic case," saying that it serves as "a reminder of the possible harm to the public that can result when narcotics are diverted."

Staff writer Paul Walsh contributed to this story. Maura Lerner • 612-673-7384