Assessment of the antimicrobial effectiveness of a new silver alginate wound dressing: a RCT

Abstract

Objective: To compare the efficacy and tolerability of a new ionic silver alginate matrix (Askina Calgitrol Ag) with that of a standard silver-free alginate dressing (Algosteril).

Method: Patients with locally infected chronic wounds (pressure ulcers, venous or mixed aetiology leg ulcers, diabetic foot ulcers) or acute wounds were eligible for this prospective, open-label, controlled and randomised trial. Patients were randomised to receive one of the two dressings for a two-week period. Criteria of efficacy were based on the evolution, from day 1 to day 15, of local signs of infection using a clinical score ranging from 0 to 18, and the evolution of the bacteriological status for each wound. The latter was determined by (blind) bacteriological examinations of results obtained from two biopsies performed at days 1 and 15. A three-point scale (deterioration, unchanged, improvement) was also used. Acceptability, usefulness and tolerance were also assessed.

Results: Forty-two patients (20 women and 22 men, 68.9 +/- 18.8 and 66.5 +/- 15.7 years old respectively) were randomly assigned to receive either Askina Calgitrol Ag (n=20) or Algosteril (n=22). Most had chronic wounds such as pressure ulcers (57%) or venous or mixed aetiology leg ulcers and diabetic foot ulcers (29%); few had acute wounds (14%). Clinical scores of infection were comparable in both groups at inclusion, 8.9 +/- 2.4 and 8.6 +/- 3.2 in the Askina Calgitrol Ag group and the Algosteril group respectively (not significant), but decreased significantly in both groups at day 15, 3.8 +/- 2.9 in the Askina Calgitrol Ag group (p=0.001) and 3.8 +/- 3.4 in the Algosteril group (p=0.007). There was no significant difference between the two groups at day 15. Although there was also no significant difference in bacteriological status between the treatment groups, a trend in favour of Askina Calgitrol Ag was found for the relative risk of improvement, especially in patients who were not treated with antibiotics either at the beginning of the study or during it. No differences between groups were observed regarding local tolerance, acceptability and usefulness of the dressings.

Conclusion: The regression of local signs of infection, local tolerance, acceptability and usefulness were similar for the two dressings. However, Askina Calgitrol Ag improved the bacteriological status of the wounds. Further trials are required to show that it has a positive impact on the healing process.