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ISO 20743: Textiles – Determination of antibacterial activity of textile products

Purpose and Goals

  • Evaluate and compare the antimicrobial activity of multiple textiles against a variety of microbes at different contact times in laboratory-controlled testing. 


  • This testing will be performed according to / as a modification to the International Standards Organisation’s Test Method ISO 20743. This test method is designed to determine the antibacterial properties of porous articles treated with an active biocidal agent. Sample fabrics are compared to a control fabric both at 0 hours and 24 hours of contact time. A suspension of live bacteria in a slightly nutritive solution is applied at several points to each sample. Sample fabrics are incubated at 37°C for 24 hours. Then the remaining live bacteria are recovered from each sample with neutralizing broth and dilution-plated on nutritive media to get a quantitative count of colony-forming units per gram of sample fabric and compare with the control. 
  • Each test will include one of the microbial strains:
    • Escherichia coli​ (ATCC 25922) – the standard bacteria
    • Methicillin-resistant ​Staphylococcus aureus​ (MRSA) (ATCC 33591) bacteria
    • Staphylococcus aureus (ATCC 6538) bacteria
    • Klebsiella pneumoniae (ATCC 4352) bacteria
    • Spores of ​Clostridioides difficile​ (ATCC 43598) bacteria
    • Candida auris (CDC B11903) fungus
  • Testing will include 24 total data points per microbial strain:
    • 2 materials (1 test textiles and 1 provided/in-house negative control)
      • Note: Please provide at least 10 grams of each material per time-point. 
    • 2 time-points (0 and 24 hours)
    • 3 replicates per sample at each test condition
    • 2 independent tests
  • Note: Optional GLP services are available for an additional 25% fee.
  • Note: Bulk discounts are available for 4+ samples (3+ for C. difficile or C. auris).

Data Analysis

  • In-house control results will be used to verify test validity. 
  • Data will be calculated to determine the quantifiable microbial burden in colony-forming units per gram of textile material (CFU/g) remaining on each sample.
  • Data will be analyzed to determine the consistency between replicate samples in each set (n=6).
  • Data will be analyzed to determine the percent reductions and log reductions of microbial burdens on each test material compared to the negative control at each test condition. 

Typical Turn Around Time

  • (per strain) 2 weeks following receipt of the test materials