DENVER -- A surgery technician who infected at least 16 hospital patients with hepatitis C and may have exposed thousands more pleaded guilty to some charges Friday in an agreement that includes a 20-year prison term.

Kristen Diane Parker, 26, had pleaded not guilty to the 42-count indictment but in the plea agreement Friday acknowledged guilt to five counts of tampering with a consumer product and five counts of obtaining a controlled substance by deceit or subterfuge. Prosecutors dropped the rest of the charges.

Prosecutors say Parker, who has tested positive for the disease, stole syringes filled with painkillers to feed a drug habit and replaced them with syringes she used and refilled with saline solution at two hospitals where she worked, Denver's Rose Medical Center and Colorado Springs' Audubon Surgery Center.

So far, prosecutors say at least 16 cases have been positively linked to her but health officials have said they fear 6,000 other patients may have been exposed to the incurable liver disease.

The agreement with prosecutors, which avoided a trial that was set for Monday, also calls for a 20-year prison term. She will be formally sentenced Dec. 11. She had faced a life sentence if convicted on all counts.

She repeatedly wiped her eyes with tissue and sometimes sniffled as she stood in her gray and white jail jumpsuit next to her attorney.

Parker's attorney, Gregory Graf, said his client wanted to take responsibility for her actions.

"She's devastated," he said. "She's been in constant tears ever since she learned that someone had tested positive for hepatitis C."

But one of Parker's victims, Denver resident Lauren Lollini, said Parker's remorse only goes so far.

"There's been a lot of damage that's been done and being sorry, I don't know if that's enough," Lollini said.

Lollini contracted Hepatitis C after having kidney stones removed at Rose in April. She said sweeping change is needed at hospitals and Parker's guilty plea is only the beginning. Lollini plans to pursue legislation on the state and national level that would require hospitals to switch to single-use syringes, or syringes that emit a dye after one use.

"From the beginning I knew that this wasn't just about Kristen," said Lollini. "It was about the hospital and the things they failed to do." Lollini hopes that surgical technicians will be licensed in the future. She said the changes would bring the kind of meaningful justice that a 20-year prison term would not.

"I look at the amount of people she affected. I look at the drug tampering. I look at the diverting drugs. I look at all of that and 20 years just doesn't seem like a very long time to me," said Lollini.

"The guilty plea today by Kristen Parker brings an end to a story that captured the attention of many in the state of Colorado," said Jeffrey D. Sweetin, special agent in charge of the Denver Division of the Drug Enforcement Administration. He added, "I hope, however, that this investigation will start a new awareness and discussion in our state of how the abuse of drugs by a few can affect all of us."

Graf said investigators have gentically linked 16 hepatitis cases at Rose to her. One case at Audobon may be linked to Parker.

Hollynd Hoskins, an attorney representing nine Rose patients who have tested positive for hepatitis C, said her clients were not happy with the plea deal and are considering civil action against the hospital.

Investigations have also been launched in Mount Kisco, N.Y., and in Houston, where Parker previously worked at hospitals. Last month, Northern Westchestern Hospital officials said that test results from 1,227 patients found no hepatitis C cases linked to Parker.

Hepatitis C is a blood-borne disease that can cause serious liver problems, including cirrhosis or liver cancer. The illness is treatable, but there is no cure. Symptoms can include nausea, diarrhea, fatigue, pain and jaundice.