Responding to a series of outbreaks of carbapenem-resistant enterobacteriaceae (CRE) linked to duodenoscopes, the CDC has developed an interim protocol for culturing the devices before use to create a greater of margin of safety for patients.

But as others have noted, the approach is not foolproof and could be costly if facilities determine they must purchase more scopes to adopt the protocol. Duodenoscopes are priced in the $40,000 range, according to researchers who came up with a similar protocol at the ECRI Institute, an independent research group.

The CDC protocol provides a plan to determine how scopes may be sampled and how to test the samples in a lab. (http://1.usa.gov/1MwdevG)

“Like other proposed solutions to the problem of duodenoscope-related CRE infections, we recognize that there are both pros and cons associated with using screening cultures,” Michael Bell, MD, deputy director of CDC’s division of healthcare quality promotion, wrote in a blog post. “There can be concerns about cost, as using this method will mean that the duodenoscopes will not be available for use while waiting for the results of the cultures. This could mean that a facility would need to buy additional scopes in order to be sure they have the equipment available when needed. Additionally, the failure to grow bacteria from the areas sampled may not guarantee that there are no bacteria present anywhere on the scope.”

The ECRI Institute also proposed a solution that will allow medically necessary procedures to continue at considerably less risk to patients. The problem is that endoscopic retrograde cholangiopancreatography (ERCP) — a procedure performed on some half-million U.S. patients annually — poses a risk of transmission of CRE because the bug has found a way to survive in intricately designed, hard-to-clean duodenoscopes. The scopes are primarily used for ERCP, an upper endoscopy procedure to access the pancreas, biliary tract, and liver.

ECRI advises, in a nutshell, not to use the duodenoscopes until they culture negative. ECRI issued a Hazard Report (http://bit.ly/1EhdkDF) that details the method, which would keep these important procedures available to patients at reduced risk of a CRE infection. In addition, ECRI recommends hospitals conduct regular CRE surveillance through duodenoscope culturing, regardless of which reprocessing method facilities use (e.g., high-level disinfection using a liquid chemical germicide or sterilization using ethylene oxide).

This could be performed in many ways, but until further culture recommendations are available ECRI recommends one of the following approaches:

Culture every duodenoscope after reprocessing is completed and wait to release the cultured scopes until negative results are received. Culture incubation typically takes up to 48 hours.

“We believe this will provide the highest assurance of preventing CRE infections,” ECRI reported.

Since few hospitals have the luxury of stocking enough scopes to have a few idle awaiting culture results, an alternative plan would be to culture scopes weekly, starting at the end of the day Friday so the bacteria may grow over the weekend.

“This will not provide the high degree of assurance that culturing after each reprocessing cycle provides,” ECRI noted. “It also bears the risk of unknowingly using contaminated scopes between culturing intervals. However, weekly culturing will be less likely to require increases to duodenoscope inventories. It will also limit the risk of potentially exposing a large number of patients to contaminated scopes as compared to less frequent culturing.”

If a duodenoscope culture is positive, ECRI recommends repeating reprocessing using a standard method and re-culturing the instrument. If this next reprocessing results in a positive culture, consider sending the duodenoscope back to the manufacturer for further assessment or retiring it. Notify infection preventionists of all positive CRE cultures, ECRI advised.

If cultures return positive on more than one scope, consider the possibility of a CRE reservoir in the reprocessing equipment or other sources, ECRI noted.