A recent outbreak of the “superbug”, carbapenem-resistant Enterobacteriaceae (CRE) bacteria, at the Ronald Reagan UCLA Medical Center has resulted in seven confirmed infections and two deaths . The source of the outbreak was found to be two of the hospital’s seven Olympus Corp. duodenoscopes that were used between October 3 and January 28 . A total of 179 patients have been exposed [1,2]. The UCLA Medical Center is providing these individuals with free, at-home screening tests to determine if they are infected with the CRE bacteria as a result of their exposure .
What is CRE?
Carbapenem-resistant Enterobacteriaceae bacteria are part of a family of bacteria commonly found in the colon. Over time, some of these gut-dwelling pathogens have developed high-resistance against many widely used antibiotics. These bacteria contain an enzyme that breaks down carbapenem antibiotics, rendering them useless, and making it very difficult to treat patients with CRE infections. Antibiotic-resistance has become an increasing public health problem across the globe. CRE is particularly dangerous because the bacteria are able to resist “last defense” antibiotics.
Healthy individuals are generally not at risk for CRE. Infections are most common in nursing homes and hospitals, where invasive devices such as ventilators, urinary catheters, and intravenous catheters, result in exposure to CRE.
How Did This Outbreak Happen?
Duodenoscopes are a type of endoscope used to obtain material for a biopsy, treat gallstones and cancers, as well as other digestive disorders . The scope consists of flexible tubes, which are inserted into the mouth, threaded through the throat, stomach and into the small intestine . Although fairly non-invasive compared to surgery, this procedure allows for easy contamination of the devices with pathogens, such as CRE. Contaminated scopes are then able to transmit the pathogen from patient to patient [4,5]
The UCLA Medical Center duodenoscopes were cleaned according to both FDA and manufacturer guidelines, therefore the outbreak has not been traced to a break in protocol . Due to their structure and mechanics, these devices are difficult to clean. Duodenoscopes cannot be autoclaved, like a scalpel would be, because their lenses and electronics make them sensitive to high temperatures . Instead, the scopes are cleaned by hand with liquid disinfectants . These procedures are not sufficient to completely remove CRE bacteria, which can then colonize on the device .
What's Being Done?
Following this outbreak, the UCLA Medical Center has removed the two contaminated duodenoscopes and implemented a more stringent decontamination process for the remaining devices . In addition to the FDA and manufacturer cleaning guidelines, automated machines are now used for disinfection, and the devices will now be receiving off-site sterilization using ethylene oxide gas .
This outbreak is not unprecedented. Since 2012 there have been CRE outbreaks in Illinois, Pennsylvania and Washington . Furthermore, duodenoscopes are often the source of disease transmission . Thus hospitals are encouraged to re-evaluate their sterilization procedures, and consumer advocates are calling for greater disclosure to patients undergoing procedures that put them at risk for infection .