By Reuters Staff

NEW YORK (Reuters) - U.S. health regulators on Thursday announced strict new recommendations for preventing the transmission of antibiotic-resistant infections from reusable medical devices such as those that have spread recently at several hospitals.

A key change is that when manufacturers submit instructions for disinfecting the devices between uses, the Food and Drug Administration will not take the company's word that the instructions work, but will demand proof.

The FDA action followed reports last month that hundreds of patients may have been exposed to pathogens, including antibiotic-resistant bacteria, after duodenoscopes were not properly disinfected between patients. Two patients at the University of California, Los Angeles died.

The new recommendations apply, however, not only to duodenoscopes but to most medical devices intended for repeated use, including bronchoscopes and endoscopes.

To deal with the thousands of devices already in use, whose disinfection protocols were not subjected to rigorous validation, the U.S. Centers for Disease Control and Prevention released instructions for reducing the risk of transmitting infections.

As previously reported by Reuters, the protocol calls for swabbing the device after it has supposedly been disinfected and seeing if any microbes grow into detectable colonies, much as doctors take throat swabs to determine if a patient has a strep infection, before the device is used again.

The duodenoscopes at the center of the recent superbug outbreaks are made by Olympus Corp, Fujifilm Holdings Corp and Pentax.

The recommendations are based on draft proposals the FDA released for public comment in 2011 but never put into practice.

As far back as 2009, the FDA believed that transmission of infection by duodenoscopes occurred when hospitals did not properly follow manufacturers' instructions for "reprocessing," or disinfecting, the devices between use. Only recently, the agency said, did it conclude that such transmission can occur even when the instructions are followed to the letter, an indication of how difficult it is to clean the complex equipment.

As part of its review before approving a reusable device, the FDA evaluates reprocessing instructions. In the past, the agency essentially took manufacturers at their word when they claimed a procedure worked; now they will have to submit data proving so "with a high degree of assurance," the agency said.

The FDA does not, however, "have the authority to require manufacturers to change their (device's) design" even if it prevents disinfection, Dr. William Maisel, FDA's deputy center director for science, told reporters.