—By Alison McCook
In March 2013, providers at an Illinois hospital were concerned. A patient with no history of foreign travel tested positive for a rare form of Escherichia coli producing New Delhi metallo-beta-lactamase (NDM), often resistant to antibiotics. In the next five months, six more patients tested positive for the same bacteria.
Working quickly, investigators realized that many of the initial patients had undergone endoscopic retrograde cholangiopancreatography (ERCP). Reviewing the records, they saw that the duodenoscopes clinicians had used in the procedures had no known defects. All had been reprocessed according to instructions, including pre-cleaning, manually cleaning and high-level disinfection using an automated endoscope reprocessor. And yet, when investigators sampled a reprocessed duodenoscope, it tested positive for NDM-producing E. coli. Over the course of 2013, a total of 39 people became infected (JAMA 2014;312[14]:1447-1455).
As a result of this outbreak, the hospital changed its duodenoscope reprocessing procedure from using high-level disinfection to sterilization, designed to kill all microorganisms—in their case, using ethylene oxide. Some experts have called for other facilities to do the same, and sterilize all flexible endoscopes. But others have urged caution, citing the cost associated with purchasing sterilizing equipment or outsourcing it, and the potential health risks associated with occupational exposure to ethylene oxide. The FDA has suggested sterilizing ERCP endoscopes if possible, and adopting other supplemental practices, such as culturing scopes and repeating high-level disinfection. Lawrence Muscarella, PhD, the president of LFM Healthcare Solutions LLC, has a new proposal.
In a publication for bedsidebronchoscopy.com, an educational site run by Ambu, Dr. Muscarella calls on facilities to divide flexible endoscopes into three categories depending on their risk for transmitting infections to patients, and use sterilization tools for scopes that pose the highest risk, according to data, such as duodenoscopes. Scopes in the other groups should be sterilized, if possible; if sterilization is not an option and facilities suspect a scope may be contaminated, Dr. Muscarella suggests they adopt one of the FDA’s other supplemental measures in addition to reprocessing, such as taking cultures and repeating high-level disinfection.
The goal is to provide guidance to facilities that have concluded that sterilization, at least of some types of flexible endoscopes, is not feasible or practical.
“That is the impetus of the scheme I developed: to come up with a pragmatic approach that is both feasible for health care facilities and protects patients, without disrupting services,” Dr. Muscarella said.
Currently, the FDA considers flexible endoscopes such as duodenoscopes, gastrointestinal endoscopes and bronchoscopes to be “semi-critical” devices, meaning they come in contact with mucous membranes or non-intact skin but pose less of an infection risk than “critical” devices, such as surgical scalpels. According to the FDA, semi-critical devices should be sterilized when possible, or reprocessed using high-level disinfection. But sterilizing all flexible endoscopes is nearly impossible, partly because the FDA has not approved sterilization techniques for many of these devices. The current system is decidedly less than ideal: Recently, the agency recommended that facilities switch to duodenoscopes with disposable components, due to the persistent risk for infection (see sidebar).
3-Part Classification Proposed
Given that sterilizing all scopes is not feasible, Dr. Muscarella said facilities should determine which scopes they are able to sterilize, and those that are most likely to remain contaminated following reprocessing that includes high-level disinfection. The latter group of instruments—which he argued includes duodenoscopes and any other scopes that data show can carry contamination or contain complex moving parts, such as linear-array echoendoscopes—belong in his scheme’s group 1.
Group 2 devices are those that still can transmit dangerous infections but are simpler in design and easier to properly clean, according to Dr. Muscarella, and may include cystoscopes, ureteroscopes, gastroscopes and colonoscopes. These types of tools can be reprocessed using high-level disinfection, although facilities ideally should try to phase in sterilization, he added. Until that time, he recommended adopting one of the FDA’s other supplemental techniques to monitor scope safety, such as repeating high-level disinfection and/or taking cultures to check for contamination.
Group 3 scopes such as hysteroscopes and transthoracic echocardiography probes generally have a low likelihood of transmitting dangerous infections if properly cleaned, and can be reprocessed according to the manufacturers’ instructions. If persistent contamination with bacteria or damage is suspected, however, sterilization or adoption of one of the FDA’s other recommended supplemental measures may be necessary.
Dr. Muscarella said the goal of his protocol is to provide facilities advice they could feasibly follow as they try to increase their use of sterilization. “It seems different scopes are associated with different risks,” he said.
“What I wanted to do was develop a scheme that is more evidence-based; adopts a ramp-up model, rather than requiring an abrupt change in practice; and can be phased in over time without either as much disruption or placing patients at risk.”
Stratifying endoscopes by risk is a “reasonable approach,” said Jeff Wiser, a technical service engineer at 3M Center, in St. Paul, Minn. “Ideally, from a patient safety perspective, all endoscopes should be considered for sterilization, but in situations where this is not possible, focusing on the highest-risk scopes as a way to at least begin implementing endoscope sterilization is the right path.”
When considering which scopes are high risk, Mr. Wiser said he believes the category should include all scopes and scope accessories that come in contact with sterile tissue, not just those linked to outbreaks.
The bottom line, said Dr. Muscarella: Sterilization is optimal, but for some types of endoscopes, it may not be necessary. “If we could sterilize, absolutely we should. But if it’s going to cost a ton of money and disrupt clinical practice, do we need it?” he asked. “I want to empower hospitals in a safe way.”
Dr. Muscarella has worked for Ambu, and is a consultant to a gas sterilization manufacturer. Mr. Wiser is an employee of 3M.