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Antibacterial activity of dressings containing antimicrobials is mostly evaluated using in vitro tests. However, the various methods available differ significantly in their properties and results obtained are influenced by the method selected, micro-organisms used, and extraction method, the degree of solubility or the diffusability of the test-compounds. Here, results on antimicrobial activity of silver-containing dressings obtained by agar diffusion test (ADT), challenge tests (JIS L 1902, AATCC 100), and extraction-based methods (microplate laser nephelometry (MLN), luminescent quantification of bacterial ATP (LQbATP)) using Staphylococcus aureus and Pseudomonas aeruginosa were evaluated. Furthermore, the effect of the pH on antibacterial efficacy of these dressings was investigated. All silver-containing dressings exerted antimicrobial activity in all in vitro tests and results correlated considerably well. Differences were observed testing the agent-free basic materials. They did not exhibit any antimicrobial effects in the ADT, MLN or LQbATP, since these methods depend on diffusion/extraction of an active agent. However, they showed a strong antimicrobial effect in the challenge tests as they possess a high absorptive capacity, and are able to bind and sequester micro-organisms present. Therefore, it seems recommendable to choose several tests to distinguish whether a material conveys an active effect or a passive mechanism. In addition, it could be shown that release of silver and its antimicrobial efficacy is partially pH-dependent, and that dressings themselves affect the pH. It can further be speculated that dressings' effects on pH and release of silver ions act synergistically for antimicrobial efficacy.

This document is a practical guide to the management of hyperkeratosis of the lower limb for all healthcare professionals involved in the care of patients with hyperkeratosis or those who are at risk of developing the condition, such as specialist nurses, district nurses, practice nurses, GPs, and podiatrists.

It offers pragmatic clinical recommendations for all aspects of care and introduces a novel, stepped approach to management, covering assessment, treatment and management of patients with hyperkeratosis, prevention of recurrence, and prophylactic measures for patients who may be at risk of developing the condition. The document also presents outcome measures that can be used to assess the efficacy of prevention and treatment interventions.

There is currently no standardised strategy or evidence-based national guideline for the management of hyperkeratosis and the condition is poorly represented generally in the medical literature. This document is therefore based on the best available evidence, supported by the consensus opinion of an expert working group of key opinion leaders from a wide range of disciplines, including lymphoedema, wound care, diabetes, dermatology and general practice. It aims to build on the success of the All Wales guidance on hyperkeratosis, which drew largely from the experience of its Tissue Viability Nurse Forum (AWTVNF, 2014).

In producing consensus recommendations, the expert working group recognises the many challenges facing healthcare professionals in this field, such as time constraints hindering a holistic approach, lack of cohesive national or local strategies for managing hyperkeratosis, and limited experience with newer, more efficacious technologies.

With these issues in mind, this document seeks to improve understanding of hyperkeratosis and equip healthcare professionals with the knowledge and skills necessary to recognise and treat this chronic condition effectively.

Caroline Dowsett, Chair

BACKGROUND

Wound infection plays an important role in compromised wound healing. A high bioburden impairs healing and leads to formation of a chronic wound. Distinctly higher pH values were observed in chronic wounds compared to acute wounds. However, there is only limited knowledge of pH dependency on the antibacterial efficacy of common antimicrobial substances.

METHODS

This study investigated the pH influence on the antimicrobial efficacy of povidone (PVP)-iodine, silver nitrate, chlorhexidine, octenidine and polihexanide against Staphylococcus aureus and Pseudomonas aeruginosa using the agar diffusion test and microplate laser nephelometry.

RESULTS

The bactericidal activity of chlorhexidine and octenidine was mainly pH-independent in a pH range of 5.0-9.0. In contrast, polihexanide showed a significant efficacy increase at a higher pH. It was also found that the influence of the pH on antiseptics differs among species of bacteria. For instance, S. aureus exhibited an increasing sensitivity against silver nitrate with rising pH whereas the effect on P. aeruginosa was found to be distinctly decreased. The antimicrobial effect of PVP-iodine was strongly diminished with rising pH.

CONCLUSIONS

The shift towards higher pH values in chronic wounds compared to acute wounds makes it imperative to know whether the antimicrobial efficacy of applied antimicrobial substances is altered by different pH levels. The results suggest that application of polihexanide might be advantageous for the management of wound infections, as both S. aureus and P. aeruginosa exhibited an increased susceptibility with rising pH.

OBJECTIVE

Late-stage lymphoedema is characterised by chronic swelling, shape distortion, inflammatory processes and tissue fibrosis. Our aim was to perform a clinical audit of a lymphoedema compression bandaging system (Rosidal Soft foam roll layer and figure-of-eight application of Actico cohesive inelastic bandages) specifically designed for patients with late stage lower limb lymphoedema.

METHOD

The audit explored suitability of the bandaging system, benchmarking limb volume changes with research evidence, and reporting patient and practitioner evaluations.

RESULTS

A mean reduction (33%) in excess limb volume was reported for the 11 patients with unilateral lymphoedema who completed a course of bandaging over 12 days. Mean percentage reduction of absolute limb volume after treatment was 8%. Patient and practitioner evaluations indicated the suitability of this bandage system for patients with late stage lymphoedema in terms of comfort and effectiveness.

CONCLUSION

The bandaging system is suitable for patients with late stage chronic swelling. Two parameters for calculating change in limb volume are not interchangeable. Future evaluation of the bandaging system, using validated outcome measures within a comprehensive research study is required.

DECLARATION OF INTEREST

Activa Healthcare provided financial support to the project and supplied the materials.

Aim:

Debridement and removal of biofilm is a major challenge in treatment of patients with chronic wounds. Surgical debridement requires trained personal, operation theatre and is often associated with pain but conventional methods relaying on cotton gauze may not be enough. A monofilament debrider* consisting of polyester fibres presents a fast and almost painless option for debridement. Hence, we have investigated the capacity of this monofilament debrider* to remove biofilm in vitro and compared it to cotton gauze**.

Methods:

For the wound debridement model, a S.aureus biofilm is cultivated on glass plates. The monofilament debrider* and conventional cotton gauze** were used to debride/clean the glass plates under standardized conditions (p=0.067N/cm2, v=1.6cm/s). Afterwards, the glass plates were stained with crystal violet to visualize the bacteria residuals. Plate images were obtained and all images were processed using ImageJ 1.45m.

Results:

Monofilament debrider* and cotton gauze** initially exhibited a comparable cleansing performance. However, the monofilament debrider* demonstrated a significantly higher cleansing capacity. While the monofilament debrider’ was able to achieve a retained high reduction of the biofilm over wiping several plates, gauze** quickly lost its efficacy.

Conclusions: The reduction of biofilm achieved using the monofilament debrider* is significantly higher than that of cotton gauze**. Moreover, it presents a non-invasive and therefore almost painless alternative to other. Hence, this technique should provide a valuable tool in the treatment of patients with chronic wounds to improve the quality of life as well as to safe costs.