ASTM E2180: Determining the Activity of Incorporated Antimicrobial Agent(s) In Polymeric or Hydrophobic Materials

Link: https://www.astm.org/Standards/E2180.htm

Purpose and Goals

  • Evaluate and compare the antimicrobial activity of non-porous materials in laboratory-controlled testing. 

Testing

  • This testing will be performed as a modification to the ASTM International Standard Test method E2180. 
  • Sections (dimensions to be determined) of the test material will be disinfected with an ethanol solution, then inoculated with a semi-solid slurry containing the test microorganism to form a gel with a contact area of approximately 3.0cm x 3.0cm (or equivalent). The inoculated sections will be incubated for the specified time-point in a humidified chamber. After incubation, the microbes from each section will be recovered into a neutralizing solution and then dilution-plated on nutritive agar to provide quantifiable viable microbial burden data for each section tested.
  • Each test will include one of the microbial strains:
    • Staphylococcus aureus, a Gram-positive bacteria.
    • Klebsiella pneumoniae, a Gram-negative bacteria.
    • Clostridioides difficile bacterial spores. 
    • Aspergillus niger, a black fungus.
  • Testing will include 24 total data points per microbial strain: 
    • 2 materials: 1 test materials and 1 provided/in-house negative control).
      • Note: Please provide at least 1,500 cm2 of each material per time-point. 
    • 2 time-points: 0 and 24 hours.
    • 3 replicates sections of each test material at each test condition
    • 2 independent tests
  • Note: Optional GLP services are available for an additional 25% fee.

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 square centimeter of contact area (CFU/cm2) 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) 2-4 weeks following receipt of the test materials