Technology update Evaluation of low-adherent antimicrobial dressings
A
Figure 9. Observed effect of AL-Ag dressing on a S. aureus (A) andP. aeruginosa (C) simulated colonised wound surface after a 48-hour contact period. Negligible growth of S. aureus was visually observed beneath the position where the dressing had been applied (A); no growth ofP. aeruginosa was visually observed beneath the position where the dressing had been applied (C). There was no observable evidence of S. aureus (B) or P. aeruginosa (D) growth upon the respectively removed AL-Ag dressings after the 48-hour contact period.
In addition to testing whole dressings in a B
simulated wound model, the effect of dressing orientation and cutting was also investigated. Three sections of each dressing were aseptically cut using sterile scissors (minimum 5mm wide across the full width of the dressing). Each section was applied to a seeded-agar plate with a different face in contact, ie the first with the wound contact surface exposed to the seeded- agar, the second with the upper or dressing- backing surface exposed, and the third was with a cut edge of the dressing. Plates were then incubated as above, removing the dressing to make observations and take photographs after 48 hours.
C
Statistical analyses In the in vitro bioadhesion studies, a two- sample significance test (ie t-test) was carried out using the statistical package Minitab Release 15 for Windows® 2007.
RESULTS Simulated bioadhesion There were marked differences in the adherence of fibroblasts to the silver-containing dressings tested. This was dependent on the dressing type and level of hydration or gelling effect [Figure 1 and Table 2]. Cell adherence to the tested adhesive foam
D
dressings was significantly greater in this in vitro model than that for gelling fibre dressings (p<0.001) in both the dry and pre-hydrated states. The AL-Ag dressing exhibited significantly less cell adherence (p<0.001) when compared to the adhesive foam dressings tested in both states. The HF-Ag dressing showed significantly less cell adherence (p<0.001) when compared to the AL-Ag in the dry state, and the foam dressings in both dry and pre-hydrated states. No statistical differences were observed between the foam dressings in either state. All the dressings were observed to have lower
adherence when the dressing was pre-hydrated compared to the corresponding dry dressing, but this was greater both in numerical and
References
17. Cavanagh M, Burrell R, Nadworthy PL. Evaluating antimicrobial efficacy of new commercially available silver dressings. Int Wound J 2010; 7: 394–405.
18. Parsons D, Bowler PG, Myles V, Jones SA. Silver antimicrobial dressings in wound management: A comparison of antibacterial, physical and chemical characteristics. WOUNDS 2005; 17: 222–32.
19.Walker M, Parsons D. Hydrofiber® Technology: its role in exudate management. Wounds UK 2010; 6: 31–8.
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Technology and product reviews
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