MIAMI - Federal authorities charged 107 doctors, nurses, and social workers in seven cities with Medicare fraud Wednesday in a nationwide crackdown on unrelated scams that allegedly billed the taxpayer-funded program $452 million - the highest dollar amount in a single Medicare bust in U.S. history.

It was the latest in a string of major arrests in the last two years as authorities have targeted fraud that is believed to cost the government $60 billion to $90 billion a year. Stopping Medicare's budget from hemorrhaging that money will be key to paying for President Obama's health-care overhaul.

Health and Human Services Secretary Kathleen Sebelius and Attorney General Eric H. Holder Jr. partnered in 2009 to increase enforcement by allocating more money and staff.

On Wednesday, hundreds of federal agents fanned out around the country, raiding businesses, seizing documents, and charging 107 suspects in Miami, Los Angeles, Houston, Detroit, Chicago, Tampa, Fla., and Baton Rouge, La. The government suspended payment to 52 providers as part of the investigations.

Among those arrested Wednesday were the owners of two community mental-health centers in Baton Rouge, charged with billing $225 million in scams. The owners allegedly recruited vulnerable patients, including elderly people, drug addicts, and the mentally ill. Patient charts were doctored to show services that were billed to Medicare but often never given, according to an indictment.