Hospitals that can afford it should take steps beyond those recommended by the manufacturer to clean and disinfect a type of device at the center of a recent superbug outbreak in the United States, health regulators said on Tuesday.

Health care facilities that use duodenoscopes should meticulously follow the manufacturer's cleaning instructions, the Food and Drug Administration said in a safety update. Those with resources should also take several other measures to reduce the risk of infection.

Duodenoscopes are flexible, lighted tubes inserted down the throat during a procedure called endoscopic retrograde cholangiopancreatography (ERCP) used to drain fluids from blocked pancreatic and biliary ducts.

The reusable device is a more complex instrument than other endoscopes and must be properly cleaned and disinfected after use so that pathogens are not transferred from one patient to another. Seven patients at the Ronald Reagan UCLA Medical Center were exposed to antibiotic-resistant bacteria from such devices between October and January. Two died.

In March Olympus Corp, the biggest maker of the devices, issued new cleaning instructions to replace those on the original label. The FDA recommended at the time that any facilities using the TJF-Q180V device should train staff on the new instructions and implement them as soon as possible.

In its latest safety update the FDA recommended hospitals also consider microbiological culturing to identify any bacterial contamination that may be present after the cleaning and disinfecting process has taken place.

Another option recommended by the FDA includes ethylene oxide sterilization.

"When possible and practical, duodenoscopes should be sterilized due to the greater margin of safety," the agency said. Ethylene oxide gas, it added, "may be an effective method for heat-sensitive instruments, like duodenoscopes, that can be damaged by high temperatures."

Hospitals could, alternatively, use a liquid chemical sterilizing process, the FDA said. Because the process requires rinsing with purified water following sterilization, "the device does not remain completely free of all viable microbes," the FDA said. "The concentration, exposure time and temperature of a liquid chemical sterilant are crucial."

Alternatively, the FDA said the standard high-level disinfection process could be repeated after the first one is complete.

The FDA said not all health care facilities would be able to implement any of the recommended measures, "which require specific resources, training, and expertise."

The American Hospital Association said it would share the new FDA guidance with its members and urge that they discuss it with their infection control and quality experts.

"Individual hospitals should assess the rigor of the cleansing procedures for the scopes they use and the additional advice in the FDA guidelines to determine what will work best in their organization," Nancy Foster, AHA vice president of quality and patient safety policy, said in an email.