In what the U.S. Department of Justice called on Thursday the largest health care fraud enforcement action in the agency's history, more than 400 defendants nationwide have been charged with defrauding taxpayers of $1.3 billion.

The takedown is a strong reflection of one of the new announced priorities at the DOJ under the Trump administration and new U.S. Attorney General Jeff Sessions: drugs, particularly opioid painkillers and other prescription narcotics.

Takedowns have become annual demonstrations of the federal government's commitment to combatting the health care fraud that has cost it and taxpayers billions of dollars in recent years.