Four-Hour Endpoint Assay Test

Test Objective:
To determine the effectiveness of SyDERMA® to inhibit the growth of bacteria in various growth mediums over an extended period of time.

Test Method:
The strains of bacteria were grown overnight (18 hours) on trypticase soy broth agar at 28°C, and then resuspended in sterile water to a turbidity of 40% - 50%T. The strain was then loaded into 96 well microtiter plates in which an undisclosed growth medium (mineral salts, vitamin mix, buffer) without a major carbon source. The wells also contained a tetrazolium dye based redox indicator system. Bacterial growth (metabolic respiration, or oxidation of carbon sources) was monitored by tetrazolium reduction as measured at 590 nm in a microplate reader every 5 minutes for four hours. SyDERMA® was added in a 50 µl volume to selected wells to determine its antimicrobial activity. Trypticase soy broth served as a positive growth control.

Interpretation of Assay:
The bacteria tested was tagged with the tetrazolium dye whose presence is measurable by optical density (OD). As the number of bacteria in the test culture was reduced, the OD would decrease and could therefore be measured. The amount of reduction of bacteria is express as the OD of each of the bacteria in the various mediums as shown in the chart on the following page.

Test Results:
SyDERMA®, showed superior inhibitory activity.