Clinical safety and effectiveness evaluation of a new antimicrobial wound dressing designed to manage exudate, infection and biofilm

Aquacel Ag Advantage/Ag+ Extra and Cutimed Sorbact in the management of hard-to-heal wounds: a cohort study

OBJECTIVE

To compare Aquacel Ag Advantage/Ag+ Extra (Aquacel Ag+) (Convatec, UK) and Cutimed Sorbact (Sorbact) (Essity, US) dressings indicated for the treatment of patients with venous leg ulcers (VLUs), diabetes foot ulcers (DFUs) and pressure injuries (PIs) for clinical performance and outcomes using real-world evidence in Germany and the US.

METHOD

This study was a chart audit review of patients who used either Aquacel Ag+ or Sorbact dressings in the 24 months prior to October 2022. Healthcare providers with access to electronic medical records and charts were asked to capture data via patient record forms. The quantitative data were analysed.

RESULTS

Findings in Germany were comparable between Aquacel Ag+ and Sorbact with regards to wound description, management and treatment outcomes, including percent area reduction and wound closure. A difference was that a greater proportion of Sorbact patients required surgery (0% versus 11%; p=0.039). In the US, a greater proportion of wounds were worsening before dressing in the Aquacel Ag+ cohort (49% versus 34%; p=0.010). A multinomial logistic regression yielded the result that patients who received Aquacel Ag+ were 3.53 times more likely to have the wound completely healed (p=0.033).

CONCLUSION

Both Aquacel Ag+ and Sorbact dressings are widely used in Germany and the US for patients with VLUs, DFUs and PIs. Our study found two important differences: patients who used Aquacel Ag+ were less likely to need further surgery in Germany; and in the US, there were significantly higher odds that wounds would completely heal with Aquacel Ag+ dressings compared to Sorbact.

Antimicrobial Activity of Silver-Containing Surgical Dressings in an In vitro Direct Inoculation Simulated Wound Fluid Model Against a Range of Gram-Positive and Gram-Negative Bacteria

Background: Surgical site infections can lead to serious complications and present a huge economic burden. Established wound infections can be difficult to eradicate so preventative measures, including antimicrobial dressings, are advantageous. Materials and Methods: The antimicrobial activity of an ionic silver, ethylenediaminetetraacetic acid (EDTA) and benzethonium chloride-containing (ISEB) surgical cover dressing (SCD) was compared with two other silver-containing SCDs (silver sulfate and ionic silver carboxymethylcellulose [CMC]) and a non-silver-containing CMC SCD control using an in vitro model. The dressings were tested against a range of gram-positive and gram-negative bacteria found in wound environments, including antibiotic resistant strains, using a direct inoculation simulated wound fluid (SWF) model. Dressings were fully hydrated with SWF and inoculated with a final concentration of 1 × 106 colony forming units (CFU) per 10 microliter of the challenge organisms. Dressings were incubated at 35°C ± 3°C for up to seven days; total viable counts (TVCs) were performed to determine bacterial bioburden. Results: All challenge organism levels remained high for the CMC SCD control and silver sulfate SCD throughout the test period. A greater than 95% reduction in TVCs was observed by four hours for all challenge organisms for the ISEB SCD, with non-detectable levels (<70 CFU per dressing) reached within 24 hours and sustained throughout the test period. Antimicrobial activity was less rapid with ionic silver CMC SCD, with 9 of 11 challenge organisms reaching undetectable levels within 6 to 72 hours. Conclusions: A more rapid antimicrobial activity was observed for the ISEB SCD compared with other dressings tested within this in vitro model.

Protocolo de tratamiento de heridas con apósito de hidrofibra reforzada, con plata iónica al 1,2%, potenciado con EDTA y cloruro de bencetonio para evitar la recurrencia de biopelícula

OBJECTIVE

Present a treatment protocol to avoid biofilm reformation in hard-to-heal wounds, using a hydrofiber dressing with 1.2% ionic silver, ethylenediaminetetraacetic acid and benzethonium chloride.

METHOD

A retrospective, descriptive and analytic study on the use of a treatment protocol, including three case studies. Patient records for hard-to-heal wounds were analysed according to an algorithm for biofilm detection and best-practice recommendations for wound hygiene.

RESULTS

The adopted protocol was based on three pillars: identifying clinical signs suggesting biofilm, performing wound hygiene, and applying an antibiofilm dressing.

CONCLUSION

Wound healing rates can improve after protocol implementation. Adequate control of local signs of infection and exudate, as well as visual and indirect signs of biofilm, were achieved. All patients progressed well towards wound-size reduction and closure using the hydrofiber dressing.

Protocolo de tratamiento de heridas con apósito de hidrofibra reforzada, con plata iónica al 1,2%, potenciado con EDTA y cloruro de bencetonio para evitar la recurrencia de biopelícula

Sinopsis

Objetivo:

Presentar un protocolo para evitar la reformación de biopelícula en heridas de difícil cicatrización con apósito de hidrofibra reforzada, con plata iónica al 1,2%, potenciado con ácido etilendiaminotetraacético (EDTA) y cloruro de bencetonio.

Método:

Estudio retrospectivo, descriptivo y analítico de aplicación de un protocolo de tratamiento, con tres casos de estudio de pacientes tratados en un centro de referencia internacional. Los registros de pacientes con úlceras complejas se analizaron y evaluaron de acuerdo con la inserción en el algoritmo de identificación clínica de biopelículas, y en base a las recomendaciones prácticas para la higiene de heridas.

Resultados:

El protocolo adoptado se basó en tres pilares: identificación de signos clínicos de sugerencia para la presencia de biopelícula, prácticas de higiene en las heridas, y aplicación de la cobertura de antibiopelícula.

Conclusión:

La capacidad de cicatrización de heridas con este protocolo puede considerarse alta. Los pacientes obtuvieron un adecuado control de todos los signos locales de infección y de exceso de exudado, y la desaparición de los signos visuales e indirectos de biopelícula. Todos presentaron una adecuada progresión, disminución de la superficie de la herida, y cicatrización tras el uso del apósito.

Clinical impact of an anti-biofilm Hydrofiber dressing in hard-to-heal wounds previously managed with traditional antimicrobial products and systemic antibiotics

Background

Hard-to-heal wounds are often compromised by the presence of biofilm. This presents an infection risk, yet traditional antimicrobial wound care products and systemic antibiotics are often used despite the uncertainty of therapeutic success and wound progression. The aim of this study was to investigate the clinical impact of a next-generation anti-biofilm Hydrofiber wound dressing (AQUACEL Ag+ Extra[AQAg+ E]) in hard-to-heal wounds that had previously been treated unsuccessfully with traditional silver-, iodine- or polyhexamethylene biguanide (PHMB)-containing dressings and products and/or systemic antibiotics.

Methods

Clinical case study evaluations of the anti-biofilm dressing were conducted, where deteriorating or stagnant wounds were selected by clinicians and primary dressings were replaced by the anti-biofilm dressing for up to 4 weeks, or as deemed clinically appropriate, with monitoring via case report forms. The data was stratified for cases where traditional silver-, iodine- or PHMB-containing products, or systemic antibiotics, had been used prior to the introduction of the anti-biofilm dressing.

Results

Sixty-five cases were identified for inclusion, wounds ranging in duration from 1 week to 20 years (median: 12 months). In 47 (72%) cases the wounds were stagnant, while 15 (23%) were deteriorating; 3 wounds were not recorded. After an average of 4.2 weeks of management with the anti-biofilm dressing (range: 1-11 weeks), in 11 (17%) cases the wounds had healed (i.e. complete wound closure), 40 (62%) wounds improved, 9 (14%) wounds remained the same and 5 (8%) wounds deteriorated.

Conclusions

The introduction of this anti-biofilm dressing into protocols of care that had previously involved wound management with traditional antimicrobial products and/or antibiotics was shown to facilitate improvements in the healing status of most of these hard-to-heal wounds. Dressings containing proven anti-biofilm technology, in combination with antimicrobial silver and exudate management technology, appear to be an effective alternative to traditional antimicrobial products and antibiotics in the cases presented here. The use of antimicrobial wound dressings that contain anti-biofilm technology may have a key role to play in more effective wound management and antibiotic stewardship.

Use of internally validated in vitro biofilm models to assess antibiofilm performance of silver-containing gelling fibre dressings

Objective:

To assess the efficacy of five silver-containing gelling fibre wound dressings against single-species and multispecies biofilms using internally validated, UKAS-accredited in vitro test models.

Method:

Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans single- and multispecies biofilms were cultured using Centres for Disease Control (CDC) biofilm reactors and colony drip flow reactors (CDFR). Following a 72 hour incubation period, the substrates on which biofilms were grown were rinsed to remove planktonic microorganisms and then challenged with fully hydrated silver-containing gelling fibre wound dressings. Following dressing application for 24 or 72 hours, remaining viable organisms from the treated biofilms were quantified.

Results:

In single-species in vitro models, all five antimicrobial dressings were effective in eradicating Staphylococcus aureus and Pseudomonas aeruginosa biofilm bacteria. However, only one of the five dressings (Hydrofiber technology with combination antibiofilm/antimicrobial technology) was able to eradicate the more tolerant single-species Candida albicans biofilm. In a more complex and stringent CDFR biofilm model, the hydrofiber dressing with combined antibiofilm/antimicrobial technology was the only dressing that was able to eradicate multispecies biofilms such that no viable organisms were recovered.

Conclusion:

Given the detrimental effects of biofilm on wound healing, stringent in vitro biofilm models are increasingly required to investigate the efficacy of antimicrobial dressings. Using accredited in vitro biofilm models of increasing complexity, differentiation in the performance of dressings with combined antibiofilm/antimicrobial technology against those with antimicrobial properties alone, was demonstrated.

Efectividad de un apósito de hidrofibra reforzada, con plata iónica al 1,2%, potenciado con EDTA y cloruro de bencetonio: casos de estudio

Sinopsis:

Objetivo:

Se realizó un estudio prospectivo, observacional, de seguimiento de casos en el servicio de cirugía plástica del hospital El Tunal, Bogotá, Colombia, para evaluar la efectividad de un apósito de hidrofibra reforzada, con plata iónica al 1,2%, potenciado con ácido etilendiaminotetraacético (EDTA) y cloruro de bencetonio en pacientes con heridas de difícil cicatrización.

Método:

Se incluyeron 23 pacientes con heridas de diferentes etiologías, signos locales de infección, presencia de exudado e indicadores visuales o indirectos de biofilm. Los pacientes fueron divididos en tres grupos: heridas que requerían cicatrización por segunda intención (n=10) (grupo 1), heridas con absceso (n=4) (grupo 2) y heridas en las que se requería preparar el lecho para cobertura quirúrgica (n=9) (grupo 3). El seguimiento de cada caso duró tres meses.

Resultados:

El grupo 1 demostró una disminución de exudado, infección y signos indirectos de biofilm, así como una reducción significativa de la superficie de la herida con cierre total en ocho de los 10 casos pertenecientes a este grupo. El grupo 2 logró el control de exudado y cierre de la cavidad en un promedio de 21 días. El grupo 3 obtuvo adecuada preparación del lecho de la herida y alcanzó una cobertura quirúrgica en 15 días, en promedio. No se encontraron efectos adversos en los pacientes tratados.

Conclusión:

Los resultados muestran que el apósito estudiado es efectivo para controlar exudado, infección y signos indirectos de biofilm, así como para disminuir el tamaño de la herida, lograr el cierre de heridas con absceso y preparar el lecho para una cobertura quirúrgica definitiva.

The efficacy of topical agents used in wounds for managing chronic biofilm infections: A systematic review

OBJECTIVES

Clinicians have increasingly adopted the widespread use of topical agents to manage chronic wound infections, despite limited data on their effectiveness in vivo. This study sought to evaluate the evidence for commonly employed topical agents used in wounds for the purpose of treating chronic infections caused by biofilm.

METHOD

We included in vitro, animal and human in vivo studies where topical agents were tested for their efficacy against biofilms, for use in wound care. For human studies, we only included those which utilised appropriate identification techniques for visualising and confirming the presence of biofilms.

RESULT

A total of 640 articles were identified, with 43 included after meeting eligibility. In vitro testing accounted for 90% (n = 39) of all included studies, five studies using animal models and three human in vivo studies. Sixteen different laboratory models were utilised, with the most frequent being the minimum biofilm eradication concentration (MBEC™) / well plate assay (38%, n = 15 of 39). A total of 44 commercially available topical agents were grouped into twelve categories with the most commonly tested agents being silver, iodine and polyhexamethylene biguanide (PHMB). In vitro results on efficacy demonstrated iodine as having the highest mean log10 reductions of all agents (4.81, ±3.14).

CONCLUSION

There is large disparity in the translation of laboratory studies to researchers undertaking human trials relating to the effectiveness of commercially available topical agents. There is insufficient human in vivo evidence to definitively recommend any commercially available topical agent over another for the treatment of chronic wound biofilms. The heterogeneity identified between study designs (in vitro to in vivo) further limits the generalisability of results.

Clinical and in vitro performance of an antibiofilm Hydrofiber wound dressing

OBJECTIVE

To compare the clinical and in vitro performance of a next-generation antibiofilm silver dressing (NGAD) with an established antimicrobial dressing technology that was developed before the recognition of wound biofilm as a clinical challenge.

METHOD

Real-life evaluations of challenging wounds managed previously with cadexomer iodine (CI) dressings followed by switching to NGAD were evaluated alongside electron, confocal and light microscopy images from a challenging, in vitro, exuding chronic wound model. Clinical case studies on the use of CI and NGAD dressings are presented to further explore the real-life evidence and in vitro findings.

RESULTS

We assessed 13 non-healing wounds that had been managed with protocols including CI dressings. After a median of four weeks, switching to the NGAD as primary dressing resulted in improvements in nine wounds and healing in two wounds, with associated improvements in wound bed appearance, while dressing usage was the same as or lower than before. The NGAD was observed to prevent the development of Staphylococcus aureus- Pseudomonas aeruginosa biofilm over three days, in contrast to the CI dressing, which appeared to support biofilm development once the active antimicrobial was exhausted from its carrier material. Clinical case studies exhibited this exhaustion as 'whiting out' of the dressing, with wound biofilm observed from samples taken following dressing use. Positive wound and patient outcomes were observed in two cases following the switch from a CI primary dressing to the NGAD, in highly exuding and infected wounds.

CONCLUSION

Antimicrobial dressings may be effective against biofilm in some laboratory models, but their effectiveness as a wound dressings in protocols of care must be verified clinically.

Antimicrobial Silver Nanoparticles for Wound Healing Application: Progress and Future Trends

Recent data have reported that the burden of infections related to antibiotic-resistant bacteria in the European Union and European Economic Area (EEA) can be estimated as the cumulative burden of tuberculosis, influenza, and human immunodeficiency virus (HIV). In wound management, the control of infections represents a crucial issue and a multi-billion dollar industry worldwide. For diabetic wounds ulcers, in particular, infections are related to the majority of amputations in diabetic patients, which today represent an increasing number of the elderly. The greatest barrier to healing is represented by the biofilm, an organized consortium of bacteria encapsulated in a self-produced extracellular polymeric substance with high resistance to conventional antimicrobial therapies. There is an urgent need for novel anti-biofilm strategies and novel antimicrobial agents and, in this scenario, silver nanotechnology has received tremendous attention in recent years in therapeutically enhanced healthcare. Due to its intrinsic therapeutic properties and the broad-spectrum antimicrobial efficacy, silver nanoparticles have opened new horizons towards novel approaches in the control of infections in wound healing. This review aims at providing the reader with an overview of the most recent progress in silver nanotechnology, with a special focus on the role of silver in the wound healing process.

An early, biofilm-focused wound management approach

Wound care experts at the 2019 EWMA conference described the need to adopt biofilm-based wound care, the case for silver dressings, the importance of early intervention and the benefits of effective antibiofilm technologies. Camila Fronzo, JWC chief sub editor, summarises the main points.

Fundamental aspects of the local approach to cutaneous ulcers

Ulcers or wounds can be classified as acute or chronic. Their treatment involves overall assessment of the patient and choice of suitable local therapy, and the appropriate indication and use of products. Technological progress in the field of wound treatment has increased rapidly. Constant updating, with emphasis on available scientific evidence, is necessary to offer the best approaches to patients with acute and chronic wounds. A qualitative analysis of literature was conducted to identify scientific publications that update the concepts involved in local wound treatment, to present some resources that can aid the healing process and describe the different types of dressings available. This review includes wound assessment using the acronym TIME (tissue, infection/inflammation, moisture balance and edge of wound), cleaning and debridement, infection/inflammation control, exudate control, dressing types and main indications.

The wound-healing effects of a next-generation anti-biofilm silver Hydrofiber wound dressing on deep partial-thickness wounds using a porcine model

Topical antimicrobials are widely used to control wound bioburden and facilitate wound healing; however, the fine balance between antimicrobial efficacy and non-toxicity must be achieved. This study evaluated whether an anti-biofilm silver-containing wound dressing interfered with the normal healing process in non-contaminated deep partial thickness wounds. In an in-vivo porcine wound model using 2 pigs, 96 wounds were randomly assigned to 1 of 3 dressing groups: anti-biofilm silver Hydrofiber dressing (test), silver Hydrofiber dressing (control), or polyurethane film dressing (control). Wounds were investigated for 8 days, and wound biopsies (n = 4) were taken from each dressing group, per animal, on days 2, 4, 6, and 8 after wounding and evaluated using light microscopy. No statistically significant differences were observed in the rate of reepithelialisation, white blood cell infiltration, angiogenesis, or granulation tissue formation following application of the anti-biofilm silver Hydrofiber dressing versus the 2 control dressings. Overall, epithelial thickness was similar between groups. Some differences in infiltration of specific cell types were observed between groups. There were no signs of tissue necrosis, fibrosis, or fatty infiltration in any group. An anti-biofilm silver Hydrofiber wound dressing did not cause any notable interference with normal healing processes.

Nanofibrous Electrospun Heart Decellularized Extracellular Matrix-Based Hybrid Scaffold as Wound Dressing for Reducing Scarring in Wound Healing

Produced through electrospinning, poly(l-lactide-co-caprolactone) (PLCL) membranes, which have a porous structure and are biodegradable, are of interest in various medical fields. The porous-structured electrospun membrane is particularly interesting because of several favorable properties as follows: it exudes fluid from the wound, does not build up under the wound covering, and does not cause wound desiccation. Moreover, extracellular matrix (ECM)-based structures derived by tissue decellularization have application as engineered tissue scaffolds and as supports for cellular regeneration. In particular, heart decellularized ECM (hdECM) has various pro-angiogenic factors that can induce angiogenesis for wound healing. In this regard, a nanofibrous electrospun hdECM-based hybrid scaffold (NEhdHS), which is a PLCL membrane, including hdECM as an active agent, was tested as a wound dressing to assess its fundamental biochemical and physical features in wound healing. Use of NEhdHS with its porous structure and pro-angiogenic factors is expected to provide an effective wound dressing and reduced scarring. We first demonstrate the effectiveness of a proposed decellularization protocol through analysis of dECM components and describe the mechanical properties of the fabricated NEhdHS. Next, we present an in vitro angiogenesis analysis of the NEhdHS, using a coculture system with human dermal fibroblasts and human umbilical vein endothelial cells; the results of which confirm its biocompatibility and show that the NEhdHS can significantly enhance angiogenesis over that obtained from PLCL or gelatin-containing PLCL scaffolds. We also studied the effectiveness of the NEhdHS in vivo. Using a rat excisional wound-splinting model, we show that covering the upper part of the wound with NEhdHS significantly reduces scarring in the wound healing process compared to that with PLCL or gelatin-containing PLCL scaffolds. Based upon its properties, we conclude that the NEhdHS has potential for application in wound dressing.

Microbiota of Chronic Diabetic Wounds: Ecology, Impact, and Potential for Innovative Treatment Strategies

World Health Organization considered diabetes as one of the 20th century epidemics, estimating that over 10% of the world population is diabetic or at high risk. Self-assessment studies indicate that diabetic patients consider chronic wounds to affect their quality of life more dramatically than vision loss or renal failure. In addition to being the main reason for diabetic patients' hospitalization, the economic burden of diabetic chronic wounds is close to 1% of United Kingdom and United States health systems budgets, which exceeds the funds allocated to the treatment of some types of cancer in both countries. Among the factors preceding the emergence of chronic diabetic wounds, also designated diabetic foot ulcers (DFUs), hygiene and pressure in specific areas are under patient control, while others are still far from being understood. A triple impairment in the innervation, immune responses, and vascularization associated to DFU has been extensively studied by the scientific community. However, the skin natural microbiota has only recently emerged as having a tremendous impact on DFU emergence and evolution to chronicity. Despite the great inter- and intra-variability of microbial colonizers, ongoing efforts are now focused on deciphering the impact of commensal and pathogenic microbiota on DFU etiology, as well as the mechanisms of interkingdom microbial-host communication. This review summarizes recent work in this context and offers new microbiological perspectives that may hold potential in the prevention and treatment of chronic diabetic wounds.

Enhanced Performance and Mode of Action of a Novel Antibiofilm Hydrofiber® Wound Dressing

Biofilm development in wounds is now acknowledged to be a precursor to infection and a cause of delayed healing. A next-generation antibiofilm carboxymethylcellulose silver-containing wound dressing (NGAD) has been developed to disrupt and kill biofilm microorganisms. This in vitro study aimed to compare its effectiveness against various existing wound dressings and examine its mode of action. A number of biofilm models of increasing complexity were used to culture biofilms of wound-relevant pathogens, before exposure to test dressings. Confocal microscopy, staining, and imaging of biofilm constituents, total viable counting, and elemental analysis were conducted to assess dressing antibiofilm performance. Live/dead staining and viable counting of biofilms demonstrated that the NGAD was more effective at killing biofilm bacteria than two other standard silver dressings. Staining of biofilm polysaccharides showed that the NGAD was also more effective at reducing this protective biofilm component than standard silver dressings, and image analyses confirmed the superior biofilm killing and removal performance of the NGAD. The biofilm-disruptive and silver-enhancing modes of action of the NGAD were supported by significant differences (p < 0.05) in biofilm elemental markers and silver donation. This in vitro study improves our understanding of how antibiofilm dressing technology can be effective against the challenge of biofilm.