Two 19-year-old nursing assistants faced charges of abuse and assault Wednesday for allegedly groping, spanking and spitting on seven patients at a nursing home, authorities said.

Brianna Marie Broitzman and Ashton Michelle Larson face multiple charges over the alleged abuse that was spread over several months in early 2008 at Good Samaritan Society. Four younger girls were also charged, with one pleading guilty and the others facing trials in Juvenile Court.

The allegations surfaced when a teenage nursing assistant told an administrator about alleged abuse during an exit interview, prosecutors said. Follow-up interviews by state investigators and police found that Broitzman and Larson "would talk and laugh about the incidents" with others, including young co-workers who were sometimes witnesses, according to a criminal complaint.

Broitzman and Larson, who no longer work at the home, considered the abuse "something fun to do at work," the complaint said. The two were confident they wouldn't get caught because "residents did not have their minds," a co-worker told investigators.

Many of the patients suffered from Alzheimer's disease and other dementia.

Broitzman and Larson were in court Wednesday but did not enter pleas. They were released on bail.

"I think that they are very serious charges," Freeborn County Attorney Craig Nelson said after the hearing. "We're dealing with people who are vulnerable adults. People who are clearly ... in need of our care and our concern and our monitoring."

Broitzman's attorney, Lawrence Maus, said in court: "Obviously she wants to challenge this complaint."

The criminal complaint quoted a relative of an 86-year-old patient as saying his aunt was physically, mentally and sexually abused. Broitzman and Larson allegedly poked her in the breasts and laughed when she told them to stop.

The Associated Press does not routinely identify victims of sexual abuse.

The complaint said Larson admitted lying on a bed with another patient, hugging her, kissing her forehead and telling her she loved her. Witnesses said Larson also groped the woman in bed and played with the woman's wig to make her angry, the complaint said.

The case became public in August, when the Minnesota Department of Health released a detailed report, alleging that 15 patients at the home were subjected to abuse. Prosecutors brought charges involving seven of the 15.