JACKSONVILLE, Fla. -- Brenda and Wilson Sullivan pleaded not guilty Wednesday to charges of aggravated child abuse resulting from authorities finding their 17-year-old grossly underweight and sleeping in a locked crib.

The Sullivans were arrested March 8 and initially charged with child neglect, but the charges were upgraded -- something Brenda Sullivan's lawyer found out at the arraignment.

"She was booked in and charged originally with child neglect, and the state, for whatever reason ... decided to up the charges to aggravated child abuse," attorney Lee Locket said. "We're definitely going to have to switch gears, because that up the ante quite a bit."

Aggravated child abuse is punishable by up to 30 years in prison -- twice the maximum penalty of child neglect, Locket said.

Brenda Sullivan is out on bond, but her husband is still being held on $35,000 bond.

When investigators responding to a tip to the Department of Children and Family's abuse hot line found the boy weighing only 49 pounds and sleeping in a bed that had a locked cover on the top.

That child and four other children were immediately removed from the home, but the Sullivans were not arrested until several weeks later.

After Wednesday's hearing, Lockett reiterated that Brenda Sullivan had obtained a prescription for the enclosed crib from Ohio authorities, and the couple had only lived in Florida since October.

Police had said that the prescription bed was issued only a year or two after the boy was adopted when he was only 6, and had been modified by adding a padlock and a chain.

A police report says the boy was starving and suffered psychosocial dwarfism -- a lack of physical and emotional growth caused by abuse. Authorities also say he was forced to wear a diaper.

Brenda Sullivan told a Akron, Ohio, newspaper that the couple fed the boy three meals a day plus a snack. He said the covered bed was used because the boy gorged himself at night.