Standard Test Method for Determining Antimicrobial Activity and Biofilm Resistance Properties of Tube, Yarn, or Fiber Specimens

Importancia y uso:

5.1 Although a number of standardized tests currently exist for assessing the antimicrobial activity of treated polymers and textiles, these are optimized for specimens that readily absorb the test inoculum or that have a flat surface on which the inoculum can be placed, and their use for specimens with tubular geometries or for small quantities (less than 0.5 g) of yarns or fibers requires significant manipulation of the specimen.

5.2 To adapt these methods for evaluating tubes, fiber, and yarn specimens requires distorting tubular specimens to create a flat surface or using unacceptably large quantities of fiber or yarn specimens. Rendering a test specimen having tubular geometry to a flat surface will limit its surface area available for exposure during the test and may require dissection of the specimen, which unacceptably alters it from its original state. Testing of treated fiber and yarn specimens using available standardized methods typically requires large quantities of material (greater than 0.5 g) that may not be available. In both cases, such manipulations may result in misleading results that do not reflect the antimicrobial efficacy of an unmodified specimen.

5.3 This method provides an environment in which the inoculum remains in intimate contact with the surfaces of these types of test specimens, exposing both the intraluminal and extraluminal surfaces of tubular specimens without significant modification, and requiring only small quantities of fibers or yarns to perform testing.

5.4 Classical antimicrobial test methods generally quantify the population or concentration of microorganisms that survive exposure to specimens treated with an antimicrobial agent without distinguishing whether the surviving microorganisms were in a planktonic or adhered/biofilm state.

5.4.1 The phenotypic behavior of bacteria in the biofilm state differs substantially from when they are in the planktonic state, especially with respect to susceptibility to disinfectants, sanitizers, and antimicrobial agents. Therefore, evaluating the ability of a material’s surface to resist bacterial colonization may be of equal or greater significance than its efficacy versus planktonic bacteria.

5.4.2 This method not only can assess the population of the challenge species that survives planktonic exposure to the test specimen, but also can then compare that to the population that survives in an adherent/biofilm state.

5.5 This test method is a batch-based system in which test specimens are exposed to a continuous, minimal fluid shear environment in the presence of the challenge inoculum. The appropriateness of this simulated environment relative to the intended end-use of the test material should be evaluated prior to testing.

5.6 Although this method is designed to provide an initial assessment of the antimicrobial activity exhibited by a material and its ability to resist microbial colonization under very specific test parameters, these conditions may not be representative of all environments to which the specimen may be exposed during its intended end-use. Various test parameters specified in this method can be modified to evaluate a material under conditions that may better simulate end-use environments, but such alterations of the method must be clearly described when reporting results.

Subcomité:

E35.15

Referida por:

E3371-22

Volúmen:

11.08

Número ICS:

59.080.20 (Yarns), 59.080.80 (Smart textiles)

Palabras clave:

antibacterial; antimicrobial; bacterial colonization; bactericidal; bacteriostatic; biofilm; catheter; fiber; filament; log reduction; percent reduction; quantitative antibacterial assay; suture; tube; yarn;