3 Out of 20 Scopes Harbor Bioburden, Study Shows

Three out of 20 flexible gastrointestinal (GI) endoscopes used for screening were found to harbor unacceptable levels of bioburden cells and matter from a patients body that could pose potential infection risk -- according to a study of endoscopes used at five hospitals across the U.S.

In an abstract to be presented at the 40th Annual Conference of the Association for Professionals in Infection Control and Epidemiology (APIC), researchers in the 3M Infection Prevention Division analyzed 275 flexible duodenoscopes, gastroscopes, and colonoscopes and found that 30 percent, 24 percent, and 3 percent respectively did not pass a cleanliness rating.

Three out of 20 is an unexpectedly high number of endoscopes failing a cleanliness criterion, says  Marco Bommarito, PhD, lead investigator and lead research specialist, 3M Infection Prevention Division. Clearly, wed like no endoscopes to fail a cleanliness rating.

In the last several years there have been reports of improperly cleaned endoscopes at healthcare facilities across the country, including the Veterans Administration, in which thousands of patients required testing for HIV, as well as hepatitis B and C. According to the Centers for Disease Control and Prevention, who published guidelines for reprocessing endoscopes in 2008, more healthcare-associated outbreaks have been linked to contaminated endoscopes than to any other medical device.(1) In addition, cross-contamination from flexible endoscopes has been identified by the ECRI Institute, an independent organization that researches patient safety and quality, as a leading health hazard.(2)

Annually between 15 and 20 million endoscopy procedures are conducted with reusable endoscope devices to screen various components of a patients GI tract. These devices allow healthcare providers to investigate the surface of this organ and identify issues such as polyps or colon cancer. Duodenoscopes, gastroscopes, and colonoscopes examine the duodenum or the first section of the small intestine, the stomach, and the colon, respectively.

After an endoscope is used for a procedure it is sent for cleaning before being reused with another patient. This reprocessing involves two steps: first, manual cleaning with an enzymatic cleaner and flushing by a hospital technician and second, soaking the device in a high-level disinfectant. The first step is vital to ensure that the disinfection process is effective. After manual cleaning is completed, the technician visually inspects the instrument to ensure cleanliness. However, this study has found that contamination can remain on the device and may be invisible to the naked eye.

In the study, after the manual cleaning step of the decontamination and disinfection process, cleaning technicians at five hospitals across the U.S. were asked to flush the scopes with sterile water, and this sample was analyzed by researchers for adenosine triphosphate (ATP) a marker of bio contamination. The amount of ATP, in relative light units (RLUs), was measured with a hand-held luminometer. Based on previously published clinical data, a threshold for pass/fail was set at 200 RLUs.iii,iv Any instruments with more than 200 RLUs were identified as a cleaning failure.

The cleaning protocols for flexible endoscopes need improvement, such as guidelines tailored to the type of scope or identifying if there is a critical step missing in the manual cleaning process, and documented quality control measures, says  Bommarito. These types of improvements could have a positive impact on patient safety. 

Source: APIC

1. http://www.cdc.gov/hicpac/pdf/guidelines/Disinfection_Nov_2008.pdf, p. 13, accessed: 5/23/13.
2. https://www.ecri.org/Documents/Reprints/Preventing_Patient_Cross-Contamination_from_Flexible_Endoscopes%28TechNation%29.pdf, p. 1, accessed: 5/23/13.
3. Michelle J. Alfa, Iram Fatima, Nancy Olson; The adenosine triphosphate test is a rapid and reliable audit tool to assess manual cleaning adequacy of flexible endoscope channels; American Journal of Infection Control, Vol. 41, Issue 3, March 2013, pp. 249-253.
4. Michelle J. Alfa, Iram Fatima, Nancy Olson; Validation of adenosine triphosphate to audit manual cleaning of flexible endoscope channels; American Journal of Infection Control, Vol. 41, Issue 3, March 2013, pp. 245-248.


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