Literature review: Endoscope disinfection failures highlight need for stronger sterilization practices

Editor's Note

High-level disinfection (HLD) fails to reliably eliminate harmful microbes from flexible endoscopes in real-world healthcare settings, according to a review of endoscope processing effectiveness published April 8 in the American Journal of Infection Control. The review highlights routine breaches in cleaning protocols and links contaminated endoscopes to numerous outbreaks, including infections with multidrug-resistant organisms (MDROs), underscoring an urgent need for improved processing standards and sterilization practices.

The review synthesized findings from 279 peer-reviewed articles, nearly 99,000 FDA adverse event reports, inspection documents, and government surveillance data spanning 2019–2024. Researchers examined processing practices and contamination outcomes for a variety of flexible endoscopes, including bronchoscopes, gastroscopes, colonoscopes, cystoscopes, and duodenoscopes. Many studies used standardized culture methods to detect microbial contamination following HLD.

Key findings include:

• Microbial contamination persisted in 6–72% of clinically used endoscopes after HLD, with frequent detection of high-concern organisms such as Pseudomonas aeruginosa, Klebsiella pneumoniae, and fungi like Candida.
• FDA-mandated studies found HCOs in 5% of duodenoscope samples and microbial growth in over 60% of samples processed according to manufacturers’ instructions.
• Dozens of outbreaks were linked to contaminated endoscopes, some involving fatalities.
• Half of patients with retained bioburden had only undergone one procedure, suggesting individual susceptibility and amplification of risk.
• Routine breaches in essential steps—including pre-treatment, leak testing, and drying—were documented across peer-reviewed studies, CMS surveys, and FDA reports.
• Manual cleaning errors were widespread, and many facilities lacked training, oversight, and functional quality assurance systems.

The review also notes that current HLD processes rely heavily on manual steps vulnerable to human error. Sterilization, which provides a higher margin of safety, eliminates this variability. However, most flexible endoscopes are still processed using HLD, even for procedures that may contact sterile tissue due to injury or device malfunction.

The authors recommend a proactive, multidisciplinary response that includes routine audits, training, borescope inspections, and, where feasible, transitioning to sterilization methods such as ethylene oxide gas or liquid chemical sterilization. They stress that investment in sterilization infrastructure and training is essential to prevent future infections, pseudo-outbreaks, and patient harm.