Nurses can handle much of the strain that health care reform will place on doctors and should be given both the education and the authority to take on more medical duties, the U.S. Institute of Medicine said yesterday.

A report from the institute calls for an overhaul in the responsibility and training of nurses and says doing so is key to improving the fragmented and expensive U.S. health care system — President Barack Obama’s signature political initiative.

But the American Medical Association, which represents about 120,000 practicing physicians as well as students and resident doctors, quickly criticized the report.

“Nurses are critical to the health care team, but there is no substitute for education and training,” the group said in a statement.