Standardizing an in vitro procedure for the evaluation of the antimicrobial activity of wound dressings and the assessment of three wound dressings

摘要

Objectives: A wide selection of wound dressings is available on the market with varying claims of antimicrobial efficacy. A valid standard method for evaluation of their antimicrobial activity in vitro has not been established. In this study we suggest a standardized time-kill assay procedure for antimicrobial activity evaluation of wound dressings in order to make studies more comparable and reproducible. We also tested two silver-containing dressings and one propolis-containing dressing against Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli and Pseudomonas aeruginosa using our proposed procedure. Methods: The following dressings were tested: the ionic silver-containing dressing (ISCD), nanocrystalline silver coated dressing (NSCD) and a propolis-containing dressing (PCD) that is in development. A time-kill assay and the zone of inhibition test were used in the study. Results: NSCD exhibited the most potent antibacterial activity against all organisms. ISDC also demonstrated good antibacterial activity although inferior to NSCD. PCD did not show any bactericidal effect. Conclusions: Based on our findings we suggest that a time-kill assay with a 1 cm. 2 dressing is used for evaluation of the antimicrobial activity of wound dressings, and that the dressings should be exposed to a standardized inoculum of 1-1.5 × 10. 6 cfu/mL with Mueller-Hinton broth as the most appropriate medium. PCD requires further research to establish its clinical value.