Responding to a series of infections connected to inadequately sterilized duodenoscopes, the FDA on Tuesday released a set of “supplemental reprocessing measures” aimed at minimizing the risk of residual pathogens on these devices.

Among the steps the agency suggested in a detailed MedWatch statement:

• Microbiological culturing on a regular basis to assess adequacy of reprocessing
• Use of ethylene oxide (EtO) gas sterilization following manual cleaning
• Following EtO sterilization with a liquid sterilizing treatment
• Repeat “high level disinfection” such as with manually applied liquid disinfectants or with automated endoscope reprocessors

“We recognize that not all health care facilities can implement one or more of these measures, which require specific resources, training, and expertise,” the agency said in announcing the new list of procedures. “Therefore, it is critical that staff responsible for reprocessing duodenoscopes have the manufacturer’s instructions readily available to promote strict adherence to the reprocessing instructions in the device labeling, understand the importance of their role in reprocessing the device, and maintain proficiency in performing these reprocessing tasks.”

The FDA also acknowledged that, even with all these procedures followed, “there will always be a risk of infection transmission with devices used internally.”

An expert panel discussion held in May informed the recommendations, the agency said. During that meeting, panel members agreed that duodenoscopes were not entirely safe and cannot be made so, but also that the devices remain indispensable in gastroenterology.

The examination of duodenoscope safety came after reports earlier this year of more than a dozen deaths from carbapenem-resistant Enterobacteriaceae infections at centers in Los Angeles and Seattle, as well as infection clusters elsewhere going back to early 2013 — all linked to reprocessed duodenoscopes.