Serielle Hygiene- Untersuchungen  von Endoskopen:  Retrospektive Analyse über 5 Jahre

Welslau, Alexandra Natascha

Thesis

Open Access

Serielle Hygiene- Untersuchungen von Endoskopen: Retrospektive Analyse über 5 Jahre

Files

danw.pdf (8.24 MB)

Date

2026-02-02

Authors

Welslau, Alexandra Natascha

Supervisors

Person

Denzer (Prof. Dr. med), Ulrike Walburga

Person

Bekeredjian-Ding, Isabelle

Abstract

The number of endoscopic procedures continues to increase. As a result, there is growing interest in the safety of endoscopy. In recent years, publications have appeared on the incidence of infections caused by endoscopes. In this study, microbiological swabs routinely taken in accordance with Commission for Hospital Hygiene and Infection Prevention guidelines at the endoscopy unit of the University Hospital of Marburg were examined over a period of five years. In particular, the bacterial load of borrowed endoscopes, which were all mechanically reprocessed twice and microbially sampled before they were used for the first time, in deviation from the German guidelines, was investigated. The mechanical reprocessing as well as the sampling and subsequent microbiological control followed the guidelines of the Robert Koch Institute. A sample was to be rejected if either pathogenic microorganisms were detected or if, regardless of the germ, it was detectable in a quantity >1 Colony-forming unit/ml. Of the 308 endoscopes tested, 16 samples were rejected (5.2%). In 5 cases, pathogenic microorganisms were detected, such as enterococci (4x) and greening streptococci (1x), indicating inadequate cleaning or disinfection, and pseudomonas (1x), indicating inadequate final rinsing or drying. The quantitative requirement was not met in 12 cases. The majority of these samples contained coagulase-negative staphylococci, indicating inadequate hand hygiene, drying or storage. The most common objectionable samples were the liquid samples. In particular, the working channel irrigation fluid (10x) and the optical irrigation system irrigation fluid (9x) were contaminated. Contrary to most previously published studies, no differences were found between endoscope types. However, rented endoscopes, which were all tested prior to their first use, showed a significantly higher rate of complaints, despite double reprocessing (p = 0.0053). With regard to hygiene- relevant germs and the main occurrence of germs in fluid samples, the following points are important: good brush cleaning to reduce biofilm and regular staff training with a focus on the specifics of the individual endoscope types. The main problem in this random sample study was skin and environmental germs, indicating inadequate drying, hand hygiene or handling of the endoscope after mechanical reprocessing. Therefore, the focus should be on proper hand disinfection in the routine and adequate drying of the endoscopes, e.g. by extending this step in the washer- disinfector or by drying the channels with compressed air. Further research should be conducted to determine to what extent storage cabinets with a special drying system can help prevent recontamination. The high rate of relevant contamination in the rental units was surprising. Due to the different sample selection of the loaned devices and the in- house endoscopes (all loaned devices vs. samples of the in- house devices according to guideline), a bias cannot be ruled out. Insufficient drying and storage can be discussed as possible causes of the complaint. The infrequent use of loaned devices and the fact that they are transported in closed cases can lead to increased drying and the formation of a biofilm, which makes subsequent reprocessing more difficult and sometimes ineffective. Possible colonization of the transport case or micro- lesions on the exterior of the loaned device caused by transport would also be causes of contamination to be considered. It can be seen that loaned devices should be handled with more care and that a double processing does not provide any advantage in terms of germ reduction compared to a single processing.