Current techniques used to clean endoscopes for reuse are not consistently effective, according to US infection control experts.
The findings support the need for careful visual inspection and cleaning verification tests to ensure that endoscopes are free of damage and debris before they are used on another patient, they said.
“The endoscopes in this study had visible signs of damage and debris”
The study, published in the American Journal of Infection Control, was carried out by medical research company Ofstead and Associates, and the University of Minnesota Medical School.
Currently, flexible endoscopes, including gastrointestinal, urological, and respiratory endoscopes, are reused following cleaning and high-level disinfection, noted the researchers.
However, results from their new study suggested that even more rigorous reprocessing techniques of endoscopes were not consistently effective, and organic residues often remain.
They carried out three assessments of 20 endoscopes over a seven-month period to identify endoscopes that required further cleaning and maintenance.
Assessments involved visual inspections with a tiny camera, microbial cultures, and biochemical tests to detect protein and adenosine triphosphate (ATP) – a marker that identifies organic matter.
During the final assessment, the researchers found that all 20 endoscopes examined had visual irregularities, such as fluid, discoloration and debris in channels.
“APIC is concerned about the risk of infections related to endoscopic procedures”
In addition, samples from 60% had microbial growth, indicating a failure of the disinfection process, and 20% of endoscopes in each group exceeded post-cleaning benchmarks for ATP and protein residue.
Moreover, ATP levels were higher for gastroscopes, which are used for upper GI procedures, compared to the endoscopes used for colonoscopy.
The researchers suggested the finding meant something was happening to gastroscopes during procedures that changed the surfaces and causes reprocessing failures.
Overall, the researchers concluded: “These findings bolster the need for routine visual inspection and cleaning verification tests recommended in new reprocessing guidelines.”
Lead study author Cori Ofstead said: “Even though top-notch methods were used, the endoscopes in this study had visible signs of damage and debris, and tests showed a high proportion were still contaminated.
Concerns raised over infection risk from endoscopes
“The finding of residual fluid in 95% of endoscopes tested was significant because moisture fosters microbial growth and the development of biofilm – which can be difficult or impossible to remove,” she said.
“This confirms the importance of cleaning, disinfecting, and drying to ensure patient safety,” she added.
Linda Greene, a nurse and president of the Association for Professionals in Infection Control and Epidemiology, said she was “concerned about the risk of infections related to endoscopic procedures”.
“This study reinforces the importance of having strong infection prevention and control programmes at all types of facilities, led by highly trained infection preventionists, to ensure that facilities are following the latest evidenced-based guidance,” she said.