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[Microbial contamination of wash water in automatic washing and disinfection machines]
A Kolch1, L Krizek, D Schoenen
1Hygiene-Institut Universität Bonn.
Abstract:
Samples were taken from the water containing tube system of 7 cleaning and disinfection machines located at the university clinics. The machines were used for the treatment of medical tools. The samples were bacteriologically examined. The results showed systemic contaminations of the tubes of all tested machines. The well known positive effect of common ion-exchangers on bacterial growth was not the only reason for the high degree of microbial contaminations. Partial bacterial growth on the inner sides of the water tubes was detected. The reason was the use of bacteriological objectionable tube materials. Recontamination of the post treated medical tools is possible at any time by the last washing water. Preceding sterile filtration showed as supposed no effect. Consequences for the use of cleaning and disinfection machines are discussed.
Insights
Microbial contamination was found in all tested cleaning and disinfection machines at university clinics. Bacteriological objectionable tube materials in these medical device reprocessing machines promote bacterial growth, risking recontamination of treated tools.
Area of Science:
- Microbiology
- Materials Science
Context:
- Medical device reprocessing is critical in healthcare settings.
- Cleaning and disinfection machines are widely used in university clinics for medical tool treatment.
Purpose:
- To investigate the cause of systemic microbial contamination in the water tube systems of cleaning and disinfection machines.
- To identify factors contributing to bacterial growth within these machines.
Summary:
- Bacteriological examination of water tubes from seven cleaning and disinfection machines revealed systemic contamination.
- Bacterial growth was observed on the inner surfaces of tubes, attributed to the use of bacteriological objectionable materials, not solely ion-exchangers.
- Sterile filtration did not prevent contamination, and recontamination of treated medical tools is a risk.
Impact:
- Highlights the need for careful selection of materials in medical device reprocessing equipment.
- Suggests that current cleaning and disinfection machine designs may pose a risk of microbial recontamination.
- Underscores the importance of addressing material-related contamination pathways to ensure patient safety.