Antimicrobial assessment of a chitosan microfibre dressing: a natural antimicrobial

Chitosan is a natural biopolymer and is the main structural component of the cuticles of crustaceans, insects and molluscs and the cell walls of certain fungi. It is abundant in nature and is naturally antimicrobial. A natural fibre has been created with chitosan and is being used as a wound dressing, namely Kytocel. It is an absorbent fibre dressing that is claimed to be biodegradable and biocompatible. This study was undertaken to assess the antimicrobial properties of the microfibre wound dressing using a variety of methods commonly used to assess other antimicrobial dressings.

The zone of inhibition (ZOI) assay, challenge test (log reduction), time-to-kill and an in vitro wound model were all used in this report. Representative Gram-positive and Gram-negative bacteria were used and one yeast, Candida albicans.

The ZoI test showed no observable zones around the dressing but killed the organisms underneath the dressing. There was a >3 log reduction of Staphylococcus aureus and Escherichia coli within two hours and >3 log reduction against Pseudomonas aeruginosa and Candida albicans between four and 24 hours in the challenge test. In the wound model, there was a 2 log reduction of Escherichia coli within the wound model and in the sponge and culture medium below the dressing.

The chitosan microfibre wound dressing gives wound care an additional dressing to use to help prevent and manage bioburden and wound infection.