WASHINGTON (AP) — Nearly 100 people, including 14 doctors and nurses, were charged for their roles in separate Medicare scams that collectively billed the taxpayer-funded program for roughly $223 million in bogus charges in a massive bust spanning eight cities, federal authorities said Tuesday.

It was the latest in a string of similar announcements by Health and Human Services Secretary Kathleen Sebelius and Attorney General Eric Holder as federal authorities crack down on fraud that's believed to cost the program between $60 billion and $90 billion each year. Stopping Medicare's budget from hemorrhaging that money will be key to paying for President Barack Obama's health care overhaul. Sebelius and Holder partnered in 2009 to increase enforcement by allocating more money and staff and creating strike forces in fraud hot spots around the country.

Miami, long known as ground zero for the complex scams, was again at the center of Tuesday's busts with 25 people charged for their role in various schemes. Authorities allege five defendants in one scheme bribed Medicare patients for their ID numbers, allowing them to bill for $51 million in home health services that were never given or were not medically necessary.

Nearly 20 people, including two doctors, a physician's assistant and two therapists, were charged in various scams in Detroit. In one case, three posed as licensed physicians and wrote bogus prescriptions for drugs and psychotherapy services totaling $12 million, the Health and Human Services and Justice departments said in a statement.

In Los Angeles, 13 people were charged in various scams totaling $23 million. In one case, authorities said three people hired workers to recruit Medicare patients. Once the defendants received the patient's Medicare ID numbers, they worked with doctors and medical clinics to get prescriptions for power wheelchairs, which they sold for kickbacks, authorities said in a statement.

Roughly 400 agents fanned out across the country as part of Tuesday's arrests raiding businesses, seizing documents and charging 89 suspects in Miami, Los Angeles, Houston, Brooklyn, Detroit, Chicago, Tampa, Fla., and Baton Rouge, La.

Four doctors were charged in various scams in Chicago and Brooklyn.

Sebelius hailed the Affordable Care Act as one of the best tools we have to "preserve Medicare and protect the tens of millions of Americans who rely on it each day."

The law makes it harder for criminals to submit fraudulent Medicare claims and allows the government to suspend payments once they're caught.

Medicare fraud has adapted into complex schemes over the years, moving from medical equipment and HIV infusion fraud to ambulance scams, as crooks try to stay one step ahead of authorities. The scams have also grown more sophisticated using recruiters who are paid kickbacks for finding patients, while doctors, nurses and company owners coordinate to appear to deliver medical services that they are not.

For decades, Medicare has operated under a pay-and-chase system, paying providers first and investigating suspicious claims later. The system worked when the agency was paying hospitals and institutions that couldn't close up shop and flee the country if they'd been overpaid. Federal authorities are using new technology designed to flag suspicious claims before they are paid, but the system is still in its infancy.

Tuesday's bust marks the sixth national Medicare fraud takedown under the strike force teams. Nearly 600 individuals have been charged in schemes involving almost $2 billion, the Health and Human Services and Justice department said.

"Taxpayers expect us to work harder and smarter, and that is exactly what happened across the nation today," said Health and Human Services inspector general Daniel R. Levinson.