UV light-based reprocessing of flexible endoscopes without working channel in Oto-Rhino-Laryngology: an effective method?

Abstract

Background Reprocessing of flexible endoscopes (FEs) is often expensive, time consuming, and becomes increasingly complex, due to rising demands of hygiene. After beneficial results in reprocessing of rigid endoscopes using Impelux™ UV-C light technology, we tested the same method for reprocessing of FEs without working channel. Materials and methods Testing was performed on FEs without working channel after routine clinical use (transnasal flexible endoscopy). Disinfection consisted of mechanical precleaning and 60 s exposure to Impelux™ UV-C light technology. Bacterial contamination was tested on 50 FEs before and after disinfection. Further 50 FEs regarding protein residuals. The absolute effectiveness of the D60 was tested on 50 test bodies (RAMS) with a standardized contamination of 107 colony-forming units (CFU) of Enterococcus faecium. Results The FEs were contaminated with a high average value of 916.7 CFU (± 1057 CFU) after clinical usage. After reprocessing, an average contamination of 2.8 CFU (± 1.6) on 14% (n = 7) of the FEs was detected consisting of non-pathogenic species, the remaining FE were sterile. After reprocessing, all FEs were protein-free (< 1 μg). The artificially contaminated test bodies showed no remaining bacterial contamination after disinfection, resulting in an average absolute germ reduction of about 107 CFU. Conclusion Impelux™ UV-C light technology efficiently reduces bacterial contamination of FEs and might be useful in daily practice.

Analysis of bacterial contamination and the effectiveness of UV light-based reprocessing of everyday medical devices

“…Furthermore, almost all endoscopes were sterile and almost protein-free after reprocessing, which fulfils the regulatory requirements for "high-level" disinfection [ 18 ]. Similar results were found for flexible endoscopes without a working channel using the same technology [ 19 ]. Furthermore, the virucidal properties of the disinfection system tested here have already been investigated, which is particularly important in the current COVID 19 pandemic.…”

“…With correspondingly positioned test bodies, the light system achieved an absolute germ reduction of 6 log levels and was thus able to fulfil the requirements of the legislator for the reprocessing of semi-critical medical devices, tested so far. In another UV light-based disinfection system of the Dutch company UV Smart, similar results were achieved in the reprocessing of flexible ENT endoscopes without working channel [ 19 ]. After use on a patient, the flexible endoscopes showed an average contamination of 916.7 CFU with potentially pathogenic bacteria.…”

“…Furthermore, bacterial resistance mechanisms or biofilm-forming properties of bacteria do not lead to a reduction of the disinfecting effect of UV light [16,17]. The effectiveness of surface disinfection by UV-C light was already documented in previous studies by this research group on "semi-critical" instruments (rigid and flexible endoscopes) [18,19]. In this case, a reduction of bacterial contamination by a total of log 6 could be achieved.…”

UV-C Light-Based Surface Disinfection: Analysis of Its Virucidal Efficacy Using a Bacteriophage Model

“…UV-C radiation causes the dimerization of thymine in DNA and uracil in RNA in the irradiated microorganisms as well as RNA-protein cross-links, which leads to an inactivation [ 18 , 19 ]. In previous studies, the device tested here showed satisfactory results in terms of bactericidal efficacy for ORL-endoscopes [ 14 , 20 ]. The tested UV system was developed for the disinfection of rigid ORL-endoscopes ( Figure 2 ).…”

Shedding a light on ultraviolet-C technologies in the hospital environment

“…Although some UV-C disinfection companies claim to offer this, no definite proof of HLD with UV-C systems was found in literature. There are studies reporting up to 7-log reductions for artificially contaminated flexible endoscopes [ 48 ]. However, they often do not take the risk of genomic repair into account or have a conflict of interest.…”