Here - EWMA 2013

E-POSTER PRESENTATIONS
EP 480
E-Poster: Dressings
COMPARISON OF PASSIVE BACTERIA ELIMINATION VERSUS ACTIVE
BACTERICIDAL EFFICACY IN A QUANTITATIVE IN-VITRO AGAR DIFFUSION
ASSAY
Florian H. H. Brill 1 , Horst Braunwarth 2
1 GmbH Institut for Hygiene and Microbiology (Hamburg, Germany);
2 Coloplast GmbH (Hamburg, Germany).
Aim: Bacterial burden may delay or stop the wound healing process. For reduction of
bacterial burden different methods are applied. Recently, passive methods based on
hydrophobic interactions were presented where bacteria adhere to the wound dressing
(bacteria elimination). The aim of this in-vitro-study was to compare the capacity of
bacteria reduction with passive elimination versus active killing.
Methods: The antimicrobial efficacy of the test products was measured in an agar
diffusion assay as well as with a quantitative test method. In this method the active
agents were inactivated after the contact time and log10 reduction factor (RF) in relation
to the control dressing have been determined (10 parallels).
Contact time: 24 h
Test bacteria: Staphylococcus aureus, Pseudomonas aeruginosa
Test products (active principle): Polyurethane Foam Dressing 1 (passive elimination)
Hydrophobic Dressing 2 (hydrophobic elimination)
Silicone Dressing 3 (hydrophobic elimination)
Hydrocapillary Dressing 4 (passive elimination)
Silver Polyurethane Foam Dressing 5 (active kill).
Gaze with Water (control)
Results: The hydrophobic dressing 2 was not able to reduce the bacterial burden. All
other passive methods were able to reduce the bacteria burden (RF 0.4 – 2.1). The
active killing method with silver ions was superior (RF 6.8 – 8.7) (figure 1).
Conclusion: Our data show that also passive elimination of bacteria from wounds e.g.
with polyurethane foam dressings may lead to a significant reduction. However, the
antibacterial efficacy of a silver foam dressing is superior compared to passive
elimination.
1 Biatain Foam Dressing, 2 Cutimed Sorbact, 3 Cutimed Siltec, 4 Alione Hydrocapillary Dressing, 5 Biatain Ag
Foam Dressing
E-POSTER: DRESSINGS
EP 481
E-Poster: Dressings
COMPARISON OF HYDROPHOBIC CHARACTERISTICS FROM DIFFERENT
WOUND DRESSINGS
Horst Braunwarth 1 , Florian H. H. Brill 2
1 Coloplast GmbH (Hamburg, Germany);
2 Dr. Brill + Partner GmbH – Institute for Hygiene and Microbiology (Hamburg, Germany).
Aim: Recently, wound dressings which claiming hydrophobic characteristics were
presented. The hydrophobic effect should be responsible for irreversible binding of
bacteria to the dressing. The aim of this in-vitro-study was to compare the hydrophobic
characteristics of these with other wound dressings.
Methods: Hydrophobic characteristics can be measured with the surface tension. The
surface tension indicates how easy water can spread onto a solid material. To measure
the surface tension, water drops were placed on test surfaces and contact angles were
measured. A contact angle of 0° shows that a surface is hydrophilic; contact angels of
around 90° indicate a hydrophobic surface. If significant higher angles are measured
these surfaces are characterized as “super hydrophobic” and have the ability to show the
famous “Lotus-effect”.
Test surfaces (claim): Polyurethane Foam Dressing 1 (no hydrophobic)
Polyurethane Foam Dressing Adhesive 2 (no hydrophobic)
Hydrophobic Dressing 3 (hydrophobic)
Soaking Hydrophobic Dressing 4 (hydrophobic)
Hydroactive Hydrophobic Dressing5 (hydrophobic)
Silicone Dressing 6 (hydrophobic)
Silicone Dressing 7 (hydrophobic)
Gaze with water (control)
Results: The results show, that all test dressings regardless if they claim a hydrophobic
characteristic have hydrophobic characteristics (figure 1 and 2).
Conclusion: Our data show that polyurethane foam dressings as well as hydrophobic
dressings have hydrophobic characteristics. It is expected that also other synthetic
dressings which have not been tested show these characteristics. To our opinion,
hydrophobic characteristics are no sufficient indicator for their clinical efficiency.
1 Biatain Foam Dressing, 2 Biatain Foam Dressing Adhesive, 3 Cutimed Sorbact, 4 Cutimed Sorbact Compress, 5
Cutimed Sorbact Hydroactive, 6 Cutimed Siltec L, 7 Cutimed Siltec
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