Intubation is a broad term. There are bronchoscopes, endoscopes, rhinolaryngoscopes, nasopharyngoscopes, and many other tubes that enter sick patients to provide a look inside. Collectively, these scopes enable life-saving procedures. But they may also harbor deadly bacteria. If contaminated devices are reused, they could infect other patients. But does this actually happen?

Lawrence F. Muscarella, PhD, (president of LFM Healthcare Solutions LLC) recently investigated this question for Ambu. He provided a case series to determine if a specific kind of scope—flexible intubation endoscopes—are associated with deadly, multidrug-resistant bacterial infections.

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The case series focused on dangerous carbapenem-resistant Enterobacteriaceae (CRE) and related multidrug-resistant bacteria. CRE includes KPC (Klebsiella pneumoniae carbapenamase). KPC and other CRE bacteria can secrete antibiotic-destroying enzymes, like NDM (New Delhi metallo-β-lactamase) or other ESBLs (extended-spectrum beta-lactamases). These enzymes render even the most sophisticated antibiotics useless.

Dr. Muscarella cross-checked two publicly available databases to identify infections caused by contaminated intubation endoscopes. First, he scanned over five years of reports from the FDA’s medical device database (MAUDE) that houses medical device reports from manufacturers, hospitals, health care professionals, and patients. These reports were cross-checked with research reports published on MEDLINE during the same time period, to include any published journal articles discussing an association between intubation endoscopes and multidrug-resistant bacteria.

Several relevant cases emerged. Although the risk cannot be ruled out, none directly linked CRE transmission to contaminated flexible intubation endoscopes, but many cases were concerning. There were no FDA alerts or federal notices focusing on the risk of flexible intubation endoscopes transmitting multidrug-resistant infections. Two intubation endoscope recalls initiated by manufacturers were identified, but these appeared to be proactive and not linked to any specific infection risk.

In 2013, a manufacturer submitted four nearly identical regulatory reports to the FDA (see FDA regulatory reports #1221826-2013-00052 through -00055). The reports linked a flexible intubation endoscope to five K. pneumoniae infections at a healthcare facility in an undisclosed location. Three of the infected patients died. The reports stated “[t]here is no indication detectable that the endoscope itself was the root cause of the infection,” however the endoscope was tested and confirmed to be contaminated with “resistant” K. pneumoniae.

Improper cleaning—use of an undersized cleaning brush, in fact—was identified as a possible cause. Once the hospital swapped the brush for one of an appropriate size, the reports states the endoscope no longer tested positive for the bacteria.

The same year, a separate research article linked a flexible intubation endoscope to five infections caused by heat-resistant, extended-spectrum beta-lactamase-producing K. pneumoniae at a hospital in Norway. The article states after taking samples, “a contaminated fiberoptic intubation endoscope was the outbreak source.” It’s possible this research article represents the same five K. pneumoniae infections described in the FDA reports, but this couldn’t be verified given limited details in the federal reports.

Another device manufacturer submitted two virtually identical regulatory reports to the FDA in 2017 describing a “cross contamination event” (see regulatory reports #9610877-2017-00406 and -407). In this instance, a patient became infected with K. pneumoniae after intubation with a flexible endoscope. The same endoscope had been used previously on a patient who tested positive for the same bacteria at the time of the procedure. Both patients died (but not necessarily because of the infection). The manufacturer who reported the case described the reusable endoscope in question as “leaky” with “perforated bending rubber” among other signs of wear and tear.

These reports suggest flexible intubation endoscopes could pose a serious infection risk, possibly from deadly, multidrug-resistant bacteria. While none of the reports could specifically confirm CRE transmission (the FDA reports lacked drug resistance profiles), the evidence is enough to make any patient or provider cautious. Fortunately, the reports also suggest that improved cleaning and endoscope reprocessing practices can eliminate contamination.

Hospitals can learn from these cases, and many more reporting contamination due to other types of scopes. Duodenoscopes in particular have been a deadly source of biofilms containing multidrug-resistant bacteria, including CRE. In 2017, a manufacturer linked a duodenoscope to a potentially untreatable infection (FDA reports #9610877-2017-00412, and 6753465). This time the K. pneumoniae species found on the duodenoscope contained the dangerous MCR-1 gene, conferring resistance to colistin—truly the last antibiotic available to treat multidrug-resistant bacteria.

The FDA now recommends healthcare facilities performing certain kinds of procedures consider extra cleaning steps for their duodenoscopes. These include additional microbiologic sampling and quarantining of contaminated scopes, cleaning twice, or using ethylene gas or liquid chemicals to help reprocess duodenoscopes. It’s possible these extra steps, when combined with the manufacturer’s reprocessing recommendations, may also be applicable to intubation endoscopes in some clinical circumstances, according to Dr. Muscarella’s research.

Flexible intubation endoscopes appear not to be subject to the same federal guidelines as other scopes. As the case series explained, endoscopes (FDA product code: CAL) do not ordinarily need to obtain 510(k) clearance from the FDA before they are sold. This means there might not be validation studies performed to demonstrate the device is as safe and effective as other devices on the market. In this way, the FDA may never review the device’s reprocessing instructions—until it’s too late. Other similar types of devices, like flexible bronchoscopes (EOQ) and nasopharyngoscopes (EQN or EOB), however, are subject to more stringent clearances.

It’s therefore up to hospitals, healthcare providers, and manufacturers to improve endoscope safety. Manufacturers are designing simpler, single-use scopes, with fewer nooks and crannies for bacteria. And the new case series outlines several steps that can help keep patients safe:

  • Follow the manufacturer’s endoscope reprocessing instructions, and consider supplementing them when warranted by clinical circumstances (e.g., in an outbreak setting). If possible, sterilize the endoscopes.
  • Visually inspect endoscopes prior to use. Don’t use damaged scopes.
  • Promptly report to the FDA suspected cases of a contaminated endoscope infecting a patient.
  • Routinely service and maintain endoscopes through the manufacturer or a manufacturer-approved or certified third-party vendor.

These extra measures could mean the difference between life and death for patients. For hospitals, they could prevent an outbreak from a potentially untreatable strain of multidrug-resistant bacteria. The case series confirms flexible intubation endoscopes are not immune to contamination risks. Like other types of scopes, they must be cleaned—and reprocessed—with extreme diligence.

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Read more by Dr. Muscarella about reducing cross-contamination risk

Source: “Resistant Klebsiella pneumoniae infections Linked to Flexible Intubation Endoscopes: Recommendations to Prevent Infections” a white paper by Lawrence F. Muscarella, PhD, sponsored by Ambu Corp.