A grand jury indicted a surgery technician infected with hepatitis C on several charges Thursday, alleging she stole syringes with painkillers and replaced them with needles she had used. Prosecutors allege that at least 19 people contracted the disease as a result.

The allegations by prosecutors, also made Thursday, are the first direct link of hepatitis C cases to 26-year-old Kristen Diane Parker, who has tested positive for the ailment. Her attorney, Gregory Graf, did not immediately return a message.

Thursday's indictment charges Parker with 21 counts of tampering with a consumer product and 21 counts of obtaining a controlled substance by deceit and subterfuge.

Officials say up to 6,000 patients at Denver's Rose Medical Center and Audubon Surgery Center in Colorado Springs where Parker worked may have been exposed to the disease. Calls to spokesmen at both hospitals were not immediately returned. Parker also worked at hospitals in Mount Kisco, N.Y., and Houston. Health officials in those states have launched investigations.

Hospital and state health officials aren't sure how many people were injected with Parker's dirty needles, or exposed to saline possibly contaminated by those needles. Thousands of former patients have been tested. Results have not been released by either hospital or state health officials.

All 19 hepatitis C cases have been found at Rose Medical Center.

"I am certain the 19 hepatitis C cases to date have been linked to Parker," said U.S. Attorney spokesman Jeff Dorschner.

State health officials have said they're working with the Centers for Disease Control and Prevention to trace the disease. Dorschner said the cases were linked to Parker through a review of Rose's records that found the hepatitis C in former surgery patients were of the same genotype as Parker's.

Parker is being held without bail.

In a police interview shortly before her arrest June 30, Parker said she didn't have health insurance or money to pay for a doctor after a pre-employment blood test showed she was hepatitis C positive. She also said it wasn't clear to her that she had tested positive.

The indictment handed up Thursday alleges Parker began taking the pain killers from operating rooms on Oct. 22, two days after she started working at Rose Medical Center.

Parker worked at Rose from Oct. 20 until April 13, when she was placed on administrative leave for failing a drug test. She came under suspicion at Rose about two weeks earlier when a syringe in her top scrub pocket poked a co-worker.