Federal investigators charged 91 defendants, including doctors and nurses, of allegedly bilking Medicare of around $295 million through false billing schemes, in what the government says is a Medicare anti-fraud task force's biggest single takedown in history.

Attorney General Eric Holder and Health and Human Services Secretary Kathleen Sebelius announced the fruits of the Medicare Fraud Strike Force sting operations Wednesday.

"The defendants charged in this takedown are accused of stealing precious taxpayer resources and defrauding Medicare -- jeopardizing the integrity of our health care system and our nation's most critical health care program for personal gain," Holder said in a statement.

Read about "Medicare's most wanted"

The alleged scammers operated out of eight cities, including known hotbeds of Medicare crime, like Miami and Detroit.

The government said the alleged crimes covered a variety of schemes. Some cases highlighted in the announcement include:

• 24 defendants in Miami were accused of participating in a $50 million false billing scheme. According to the feds, the defendants allegedly paid recruiters to refer ineligible patients to a mental health center. Sometimes, halfway house residents were threatened with eviction if they didn't attend the mental health center, the government said.

• Two Houston individuals were charged in $62 million false billing schemes involving home care. According to the feds, one defendant allegedly sold beneficiary information to 100 Houston-area home care agencies. The information was then allegedly used to bill Medicare for unnecessary, or never provided, services.

Since its founding in March 2007, the Strike Force, a joint DOJ-HHS team, has charged more than 1,140 defendants who have falsely billed Medicare for nearly $3 billion, the agencies said.