Technology and product reviews
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1. Dressings constructed from gelling fibres produced a lower cell adherence
2. This simple in vitro model suggests that the presence of an adhesive layer may be a physical barrier to silver contained within certain dressings
3. Dressing technology and construction may be important factors in determining the antimicrobial activity of dressings
Figure 13. Example showing foam B dressing strip orientation on the seeded agar plate.
Figure 15. (A) Observed effect of different HF-Ag dressing faces on a S. aureus seeded agar surface after a 48-hour contact period. No bacterial growth is visually observed beneath the position of each dressing strip. (B): Observed effect of different AL-Ag dressing faces on a S. aureus seeded agar surface after a 48-hour contact period. Negligible growth of S. aureus is visually observed beneath the position where the wound contact and the outer surface dressing strip had been applied. (C): Observed effect of different foam B dressing faces on a S. aureus seeded agar surface after a 48-hour contact period. Bacterial growth is visually observed beneath the position where the wound contact strip had been applied; negligible growth of S.
aureus is visually observed beneath the outer dressing surface strip. (D): Observed effect of different foam C dressing faces on a S. aureus seeded agar surface after a 48-hour contact period. Bacterial growth is visually observed beneath the position where the wound contact and the outer surface dressing strip had been applied.
close contact was observed between the dressing and agar over the whole interface between the dressing and the bacteria- seeded agar. AL-Ag was observed to be a mixture of gelling fibres and non-gelling fibres (eg silver-coated nylon fibres). The fibrous pad was contained within a
perforated outer sleeve, which limited the area of direct contact between the pad and the bacteria-seeded surface to approximately 40%. It was possible to suggest that a combination of a limited direct exposure, the nature of the source of silver and the presence of non-gelling fibres may be contributory factors to the greater cell adhesion and less effective antimicrobial performance of AL-Ag compared to HF-Ag.
47 Wounds International Vol 2 | Issue 4 | ©Wounds International 2011
CONCLUSION In these in vitro studies, dressings constructed from gelling fibres produced a lower cell adherence than certain foam dressings with an adhesive layer across the wound-contact surface, particularly in the presence of hydration. The lowest adherence was observed for HF-Ag, which was the only dressing tested to be entirely constructed from gelling fibres. Observed antimicrobial activity was highly
variable in this in vitro model, despite all the dressings containing silver and the test model being designed to eliminate the possible effect of dressing conformability and ensure direct contact between the dressing and the underlying bioburden.
Figure 14. Observed effect of different foam A dressing faces on a P. aeruginosa (A) and (B) S. aureus seeded agar surface after a 48- hour contact period. Bacterial growth is visually observed beneath the position where the wound contact and the outer surface dressing strip had been applied.
powe
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