ISO 22196: Measurement of antibacterial activity on plastics and other non-porous surfaces

Purpose and Goals

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

Testing

• Sections (50 mm x 50 mm or 1” x 3”) of the test material will be disinfected with an ethanol solution, inoculated with a liquid bacterial suspension in a slightly nutritive solution, and covered with a sterile film to ensure a contact area of approximately (40 mm x 40 mm or equivalent). The inoculated sections will be incubated for the specified time-point in a humidified chamber. After incubation, the bacteria from each section will be recovered into a neutralizing solution and then dilution-plated on nutritive agar to provide quantifiable viable bacterial burden data for each section tested.
• Each test will include one of the microbial strains:
  • Staphylococcus aureus​ ATCC 6538 (a standard test strain) bacteria
  • Methicillin-resistant ​Staphylococcus aureus​ ATCC 33592 (MRSA) bacteria
  • Klebsiella pneumoniae ATCC 4352 (a standard test strain) bacteria
  • Carbapenem-resistant Klebsiella pneumoniae ATCC BAA-1705 (KPC / CRE) bacteria
  • Candida auris CDC B11903 fungus 
  • Staphylococcus epidermidis ATCC 35984 bacteria
  • Salmonella enterica ATCC 10708 (formerly known as ​S. choleraesuis​) bacteria
  • Salmonella enterica​ ATCC 14028 (formerly known as ​S. typhimurium​) bacteria
  • Shigella flexneri ATCC 12022 bacteria
  • Escherichia coli ATCC 25922 (a standard test strain) bacteria
  • Escherichia coli ATCC 43888 (an O157:H7 strain) bacteria
  • Listeria monocytogenes ATCC 7644 bacteria
  • Pseudomonas aeruginosa ATCC 9027 or 15442 bacteria
  • Clostridioides difficile ATCC BAA-1870 or 43598 (formerly known as Clostridium difficile) bacterial spores
• Testing will include 24 total data points per microbial strain:
  • 2 materials: 1 test material and 1 in-house negative control material).
    • Note: Please provide at least 15,000 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 fee.
• Note: If a large surface must be tested intact, sterile sponges will be used to recover the bacteria from the test areas, and an additional fee of $30 per material will apply.

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 (CFU/cm²) remaining on each section.

• Data will be analyzed to determine the consistency between replicate sections 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. 

Link: https://www.iso.org/standard/54431.html