As the MDRO Threat Mounts, It’s Time to Update the Spaulding Classification


By Stephen Spanos, MD

Gastrointestinal endoscopy is common – every year doctors perform 18 million procedures in the United States. And endoscopes are increasingly being outfitted with ultra-high definition cameras, 3-D images, and other technologies to improve diagnostic performance. Yet the guidelines governing the cleaning and disinfecting of endoscopes (colonoscopes, gastroscopes, bronchoscopes, duodenoscopes, etc.) so that they can be used again are over 50 years old.

This needs to change. 

The complexity of these scopes and the fact that they invariably become highly contaminated during use, makes cleaning and disinfecting them properly between uses very difficult. It has to be done exactly right or it’s not effective in eradicating contaminants. In theory, the process of high-level disinfection (HLD) should completely eliminate all microorganisms (except small number of bacterial spores) from endoscopes. 

But repeated analysis has shown that even after being cleaned and disinfected according to protocol, 30 percent or more of endoscopes – especially duodenoscopes – remain contaminated with substantial numbers of potential pathogens. In the past few years, there have been multiple reports of patients becoming infected and even dying from exposure to pathogens from contaminated endoscopes. 

A 2018 Johns Hopkins University study published in GUT, for example, found that of the 15 million colonoscopies performed each year at U.S. ambulatory surgical centers (ASGs), 1 out of 1,000 patients was infected. The same study concluded that of the 7 million osophagogastroduodenoscopies (OGDs) performed at ambulatory centers, 3 out of 1,000 patients were infected. Infections after bronchoscopies were even higher, 16 out of 1,000.

Cori Ofstead, president and CEO of Ofstead & Associates, published a study last year in the journal Chest looking at bronchoscope contamination at three hospitals. She found that 100 percent of the scopes evaluated had residual contamination post manual cleaning. Fifty-eight percent of the fully reprocessed bronchoscopes showed microbial growth, including mold, Stenotrophomonas maltophilia, and Escherichia coli and Shigella spp. 

A study by infectious disease experts at Harvard Medical School published in the April 2019 issue of Clinical Infectious Diseases reported the first documented healthcare “transmission of mcr-1-harboring bacteria in the U.S.” The Harvard team reported that transmission “likely occurred via duodenoscope despite no identifiable breaches in reprocessing or infection control practices.” 

“Duodenoscope design flaws leading to transmission of multidrug-resistant organisms (MDROs) persist despite recent initiatives to improve device safety,” the team wrote.

In 2016, nine University of Colorado Hospital patients developed infections after undergoing surgeries with a duodenoscope. Three of the patients died, although it is unclear what role these infections played in their deaths. 

According to William A. Rutala, PhD, MPH, CIC, professor of medicine at the UNC School of Medicine and director of the Statewide Program for Infection Control and Epidemiology Division of Infectious Diseases, there have been at least nine cases of duodenoscope-related outbreaks of MDROs in the last several years. In all these cases, healthcare facilities followed proper reprocessing procedures, he said.

In an article, “What’s New in Reprocessing Endoscopes: Are We Going to Ensure the Needs of the Patient Came First by Shifting from Disinfection to Sterilization?” Rutala writes that “The Centers for Disease Control and Prevention and other investigators monitored endoscope reprocessing procedures used in these outbreaks and concluded that the institutions were compliant with the manufacturer’s instructions for use (IFU) and professional organizational recommendations.”

The rates of endoscope contamination may even be much higher. It’s difficult to detect potential pathogens quickly and completely because of inadequate surveillance methods and long lag times between contamination and infection. Generally, recognition of contamination takes place after the appearance of unusual pathogens, as was the case with New Delhi metallo-beta-lactamase (NDM)-producing E. coli. The risk level also varies by procedure, with some, such as colonoscopy, much more prone to colonization than others. The condition of the patient is another factor – whether they are older, immunocompromised, have cancer or other ailments. 

Repeated outbreaks have been blamed on inadequate cleaning and inappropriate disinfection (e.g., failure to perfuse all channels), damaged endoscopes or flaws in the design (for example, with the duodenoscope elevator channel), and issues with automated endoscope reprocessors (AERs). The complexity of endoscopes, with their unwieldy, long, narrow channels, right-angle turns, and small crevices make them extremely difficult to clean. 

In addition, microorganisms often reside in scratches, grooves, and irregular surfaces that invariably occur on endoscopes subject to regular use. If endoscopes are not completely dried after cleaning, any remaining viable microbes can rapidly proliferate and colonize the instrument. The age of the endoscope and improper storage have also been found to contribute to higher contamination rates.

“To mitigate the risk of exposure, most endoscopy centers have implemented enhanced reprocessing techniques, such as repeated high-level disinfection,” according to Rutala.

However, studies have shown that this procedure does not reduce the level of contamination of the devices. One problem is that the brushes, detergents, and disinfectants do not always get to hard-to-reach areas exposed to contaminants, even with a second cleaning. 

In addition, researchers have found that healthcare workers often don’t follow proper cleaning procedures. In addition, all the steps needed for proper manual endoscope reprocessing are rarely performed and some essential steps – for instance, brushing all endoscope channels and components – are often skipped. Many healthcare facilities have a small inventory of endoscopes and want to get them turned around for reuse quickly, often at the expense of cleanliness and patient safety. Using AERs has contributed somewhat to improved reprocessing because most steps are automated and standardized, but even this is not sufficient. 

While improvements to cleaning and monitoring guidelines and the design are important, the problem of contamination will not be solved unless we revise the way that endoscopes are classified in the Spaulding scheme. 

Developed in 1968 by Dr. Earle Spaulding, this classification scheme defined how an object should be disinfected based on its intended use. According to Dr. Spaulding’s protocol, instruments defined as “semi-critical” are any devices that contact intact mucous membranes. The recommended reprocessing guideline for semi-critical objects is cleaning followed by high-level disinfection (HLD). Items defined as “critical” are those that enter sterile tissue or the vascular system or through which blood flows, and require cleaning followed by sterilization. It should also be noted that many of the tools which are used in these endoscopes have been deemed as critical in the Spaulding classification. 

This lack of uniformity between scope and tool creates a problem, as the critical tool will become contaminated as it passes through a dirty channel.

Now that we have a clearer picture of the challenges and risks associated with endoscope reprocessing, we know that the only way to prevent further contamination is to clarify the Spaulding classification. Rutala has recommended that complex devices that directly or indirectly enter normal sterile tissue or the vascular system, such as bronchoscopes, cystoscopes, or duodenoscopes, need to be defined as critical and should require sterilization. This would mean that colonoscopes that have contact with non-intact mucous membranes would be defined as a critical item requiring sterilization. The same would apply to the duodenoscope, cystoscope, and bronchoscope, as they indirectly contact a normally sterile tissue such as bile ducts, bladder and lungs. Evidence shows that HLD of endoscopes provides little to no margin of safety, while sterilization has been proven to significantly reduce microbial contamination.

Rutala notes that the “FDA mandated a similar shift from disinfection to sterilization for dental hand pieces in 1992 … even though there were no documented cases of disease transmission associated with these instruments.”

By contrast, the infection data for endoscopes is overwhelming and irrefutable. In May 2015, an FDA panel recommended the sterilization of duodenoscopes. But reprocessing guidelines have not yet changed. To ensure patient safety, it is critical that we move from high-level disinfection to sterilization of all endoscopes.

For this to happen, Rutala has recommended that professional and consensus standard organizations such as SHEA, APIC, SGNA, ASGE, and AAMI, as well as device manufacturers, regulatory agencies, doctors, and inpatient and outpatient endoscope reprocessing centers, all need to facilitate these changes through guidelines, research, and education. New technologies are now being developed that will help: New or optimized low-temperature sterilization technologies, disposable sterile endoscopes, steam sterilization for GI endoscopes, and the growing use of non-endoscopic diagnostic methods, such as capsular endoscopy, or “liquid” biopsies to detect cancer.

Adopting these technologies as soon they are approved will add to our efforts for change. Working together on all these fronts, we can significantly reduce this serious, if still under recognized, problem.

Stephen Spanos, MD, is medical director at Ambu, which manufactures and sells medical products including bronchoscopes, resuscitators and electrodes, and is credited with developing the world’s first single-use flexible endoscope. Spanos is chairman of regional anesthesia at Primary Children’s Hospital and assistant professor in the department of anesthesiology at the University of Utah. 


Related Videos
UV-C Robots by OhmniLabs.  (Photo from OhmniLabs website.)
CDC  (Adobe Stock, unknown)
Laparoscopy(Adobe Stock 338216574 by Damian)
Sterile processing   (Adobe Stock, unknown)
Jill Holdsworth, CIC, FAPIC, NREMT, CRCST, manager of infection prevention at Emory University Hospital Midtown; and Cheron Rojo, BS, FCs, CHL, CIS, CER, CFER, CRCST, clinical education coordinator for sterile processing departments, Healthmark
The Joint Commission Seal
Jill Holdsworth and Adam Lorentz discussing urology and infection control
the Association for Professionals in Infection Control and Epidemiology (APIC) 2022 Annual Conference,