Anti-microbial testing for infection control PPE materials

Infection Control PPE, Textile Evaluation Using Pathogen Contact Transfer Testing

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High Speed Decontamination for Infection Control PPE Applications

New antimicrobial textiles have very fast rates of self decontamination. Chlorine based systems can achieve 99.9% decon in 30 sec with model pathogens.  From the standpoint of Heathcare, users need to know that their PPE textile materials are free of infectious particles. These high speed decon speeds are very helpful for PPE applications.  The contamination state of textiles in infection control PPE affects doffing and disposal behavior. When the textile self-decontaminates in 30 seconds the doffing and disposal processes are lower risk.

Slash Zone PPE Material Testing 

Measurement of textiles for pathogen contamination can be done using various test methods. AATCC Method 100 is the most common test used in the US. There are closely related methods used in Europe and Asia. Method 100 uses a pathogen challenge liquid, applied so it saturates the textile and after hold time. there is a liquid extraction from the textile used to measure the level of self-decontamination. This saturation challenge and liquid extraction assay are appropriate for bedding, wipes, dressings and other textiles used in direct contact with patients and infectious fluids. In infection control PPE, the splash zone materials are impermeable membranes like gloves or membrane textile laminates used in aprons and gowns.

Contact Transfer PPE Materials

In infection control PPE ensembles, there are textile components that are not in the splash zone in patient care and are not subject to saturation by infectious fluids. A good example is an inner glove worn to provide mechanical protection from barrier glove failure. The BioTecT self-decontaminating textile glove is not used in patient contact or exposed to contact with splash risk. In this configuration the contamination risk to the inner BioTecT glove is from pin hole failures in the outer glove or doffing related contamination when the outer gloves are removed. A useful distinction in the infection control PPE ensemble should be made between Splash Zone materials and Contact Transfer Zone materials.

Contact Transfer Zone Material Testing 

In order to evaluate these challenge conditions, a related test was developed which uses a plated liquid pathogen challenge on agar and then after hold time, a contact transfer is made to a second agar plate to measure the level of self-decontamination. Modified Method 100 for Contact Transfer Challenge Test (CTC Test)  is the new test designation. This draft test method is attached to this blog post. This method is much more consistent with the pathogen challenges that Contact Transfer Zone materials are subject to in the PPE ensemble.  Infection control PPE textile layers are used behind a barrier membrane and can be evaluated with the CTC test method. An important aspect of the CTC method is the opportunity to run the assay at speed. Because Contact Challenge and Contact Transfer assay can be preformed in seconds, the rate of self-decon can be evaluated for exposure times to 15-30 seconds. The method 100 assay is limited to exposure times greater than 10 minutes.  Using CTC testing textile contamination state can be evaluated for activities times that include doffing and donning speeds. Knowing that the textile layers in the Infection Control PPE Ensemble have completed their self decon process improves the safety of PPE systems.
If you want to test the high speed self decon BioTecT glove follow the link.
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