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The presence of fecal test soil protects bacteria during cleaning/disinfection
Poulomi Nandy1, Elizabeth A Gonzalez1, Anne D Lucas1
1Laboratory of Microbiology and Infection Control, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland, 20993.
Abstract:
Reusable medical devices (RMDs) must be reprocessed between uses to render them safe for each use and each patient. Cleaning used devices removes organic and inorganic soil making them either safe for reuse or ready for disinfection/sterilization depending on the device. Although cleaning is an important step in a RMD's life cycle, it is not always a priority during device design. In addition, when performing cleaning validation, it is recommended that the manufacturer takes into consideration, what the most appropriate or worst case conditions are in terms of type of soil or the presence of bacteria. This study compared the ability of three different cleaning/disinfecting agents (water, alcohol, and bleach) to remove bacteria and fecal test soil from two different polymers: polypropylene and ultrahigh molecular weight polyethylene (UHMWPE) with two different roughness. There were some differences in the effects of the cleaning/disinfecting agents, the materials, and the roughness depending on the particular circumstances. However, the most consistent effect on the removal of bacteria was the presence of soil, which protected the bacteria from being removed. Conversely, the presence of bacteria played little role in the removal of soil. Although the interactions between material type and roughness, soil type, and bacteria are complicated, they should be taken into account during device design and reprocessing validation to create a device that is easy and safe to use. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1706-1710, 2019.
Insights
Soil significantly protects bacteria on reusable medical devices (RMDs), hindering their removal during cleaning. Device design and reprocessing validation must consider these complex interactions for patient safety.
Area of Science:
- Biomedical Engineering
- Materials Science
- Infectious Disease Control
Background:
- Reusable medical devices (RMDs) require effective reprocessing, with cleaning being a critical but often overlooked step in device design.
- Cleaning validation should account for worst-case scenarios, including soil type and bacterial presence.
- Understanding material properties and surface characteristics is crucial for effective RMD cleaning.
Purpose of the Study:
- To compare the efficacy of water, alcohol, and bleach in removing bacteria and fecal soil from polypropylene and ultrahigh molecular weight polyethylene (UHMWPE) with varying roughness.
- To investigate the influence of material type, surface roughness, soil presence, and bacterial load on cleaning effectiveness.
- To inform device design and reprocessing validation protocols for RMDs.
Main Methods:
- Testing three cleaning/disinfecting agents: water, alcohol, and bleach.
- Utilizing two polymer types: polypropylene and UHMWPE, with different surface roughness.
- Evaluating the removal of bacterial load and fecal test soil under varied conditions.
Main Results:
- The presence of soil consistently protected bacteria, significantly impeding their removal.
- Bacteria presence had minimal impact on the removal of soil.
- Differences in cleaning agent efficacy, material type, and roughness were observed but were less consistent than the protective effect of soil.
Conclusions:
- Soil is a primary factor inhibiting bacterial removal from RMDs, underscoring its importance in cleaning validation.
- Device design should prioritize ease of cleaning, considering material properties and surface characteristics.
- Reprocessing validation must incorporate complex interactions between soil, bacteria, materials, and cleaning agents to ensure RMD safety.
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