The antimicrobial efficacy of nanocrystalline based surgical dressing and a low dose silver hydrofiber surgical dressing against common wound pathogens using log reduction methodology

Introduction: The clinician has many choices when deciding which topical antimicrobial silver to use during treatment. It is key to have some indication of how these dressings compare. In this in vitro study, the time-kill curve or log reduction method was used to assess the antimicrobial efficacy of the two dressings. As the speed of kill during a log reduction assay has been most closely linked to clinical outcomes. A time-kill kinetic assay may shed light on clinical benefits of a given dressing.  

Method: Samples were tested against a range of organisms commonly isolated from wounds. All dressings were tested in replicates of three against controls. Samples were incubated at 32^oC for 0, 4, 24, 48, 72 hours.

Results: The antimicrobial activity of a nanocrystalline based surgical dressing and a low dose silver hydrofiber surgical dressing against common wound pathogens was assessed using direct inoculation log reduction method.

Conclusions: Both dressings demonstrated bactericidal activity against most pathogens tested at one or more time points over the 3 day period. More rapid bactericidal activity was observed for the nanocrystalline based surgical dressing against a variety of organisms tested. nanocrystalline based surgical dressing demonstrated fungicidal activity at all time points against the yeast C. albicans. The low dose silver hydrofiber surgical dressing showed minimal activity against this yeast initially, with no antifungal activity from 24 h onwards.  It is hoped that studies of this type will allow for enhanced clinician education, patient safety and prove beneficial to facilities.