Dr Andrew May¹, Dr Zlatko Kopecki², Dr Bernard Carney¹, Dr Allison Cowin²

¹Women’s And Children’s Hospital, Adelaide, Australia, ²University of South Australia, Adelaide, Australia

Abstract:

Background and aims: Large wounds such as major burns are susceptible to microbial infection and resulting biofilm.1 Antimicrobial dressings such as those containing silver are therefore widely used.2 Such products require regular dressing changes and their expense means that patients often need to attend burns units for this; an additional barrier to access for regional patients. This study aimed to investigate the effectiveness of antimicrobial silver dressings if left in situ for longer than manufacturer recommendations.1

Method: Commercially available silver based dressings were tested in vitro against staphylococcus aureus (SA), pseudomonas aeruginosa (PSA) and escherichia coli (EC). The standard Kirby-Brauer diffusion disc lab assay was used, which measures the Zone of Inhibition surrounding antimicrobial agent on lawned agar plates. Fresh dressings were tested and then underwent prolonged incubation with weekly transplantation of the used dressing onto a freshly lawned agar plate. Dressings were ‘re used’ for four weeks and tested weekly. Results were analysed by one way ANOVA.

Results: Acticoat® and Acticoat 7® were initially effective against each pathogen. The zone of inhibition for Acticoat 7® remained constant throughout the study for each pathogen (p>.05). Acticoat 3® showed loss of antimicrobial efficacy after three weeks of testing for each pathogen (p<.05).

Conclusion: Acticoat® and Acticoat 7® may have a longer period of antimicrobial efficacy than originally thought. In vitro testing shows that Acticoat® may be effective for up to three weeks and Acticoat 7® may be effective for four weeks, however more research is required to examine this benefit in human subjects.

1. Aramwit, P. et al. (2010). In vitro evaluation of the antimicrobial effectiveness and moisture binding properties of wound dressings. Int J Mol Sci 11(8): 2864-2874.
2. Castellano, J. J. et al. (2007). Comparative evaluation of silver-containing antimicrobial dressings and drugs. Int Wound J 4(2): 114-122.

Biography:

Burns registrar at Women’s and Children’s Hospital Adelaide.