Improving outcomes for patients with hard-to-heal wounds following adoption of the Wound Hygiene Protocol: real-world evidence.

OBJECTIVE: To evaluate the impact of a four-step biofilm-based wound care strategy, Wound Hygiene Protocol (WHP: cleanse, debride, refashion, and dress), on hard-to-heal wounds. METHOD: This was a prospective, real-world analysis of hard-to-heal wounds managed with the WHP that incorporated Aquacel Ag+ (Convatec Ltd., UK) dressings. Data were captured electronically between April 2021 and December 2022. The primary endpoint was change in wound volume from baseline to final assessment. RESULTS: A total of 693 wounds in 669 patients (median patient age: 74 years) were included in the analysis with a median treatment time of 31 days. Most health professionals were general nurses (50%) or nurse practitioners (38%). Patient homes (27%) and community clinics (27%) were the most common clinical settings. Venous leg ulcers (26%) and pressure ulcers/injuries (17%) were the most common wound type. Duration was >12 months in 21% of wounds. At baseline, the mean wound volume was 57.8cm3. At the final assessment, mean wound volume was 17.2cm3, corresponding to an 80% reduction from baseline; p<0.001). At baseline, 66% of wounds were static or deteriorating. At final assessment, this had decreased to 5%, and 94% had improved or healed. Exudate levels were moderate or high in 69% of wounds at baseline which decreased to 25% at final assessment (p<0.001). Suspected biofilm and local wound infection decreased from 79% and 43%, respectively, at baseline, to 18% and 3%, respectively, at final assessment (p<0.001 for both). CONCLUSION: The WHP is a new proposed standard of care that successfully treated hard-to-heal wounds by addressing the key local barriers to wound healing.

A Host-Directed Approach to the Detection of Infection in Hard-to-Heal Wounds.

Wound infection is traditionally defined primarily by visual clinical signs, and secondarily by microbiological analysis of wound samples. However, these approaches have serious limitations in determining wound infection status, particularly in early phases or complex, chronic, hard-to-heal wounds. Early or predictive patient-derived biomarkers of wound infection would enable more timely and appropriate intervention. The observation that immune activation is one of the earliest responses to pathogen activity suggests that immune markers may indicate wound infection earlier and more reliably than by investigating potential pathogens themselves. One of the earliest immune responses is that of the innate immune cells (neutrophils) that are recruited to sites of infection by signals associated with cell damage. During acute infection, the neutrophils produce oxygen radicals and enzymes that either directly or indirectly destroy invading pathogens. These granular enzymes vary with cell type but include elastase, myeloperoxidase, lysozyme, and cathepsin G. Various clinical studies have demonstrated that collectively, these enzymes, are sensitive and reliable markers of both early-onset phases and established infections. The detection of innate immune cell enzymes in hard-to-heal wounds at point of care offers a new, simple, and effective approach to determining wound infection status and may offer significant advantages over uncertainties associated with clinical judgement, and the questionable value of wound microbiology. Additionally, by facilitating the detection of early wound infection, prompt, local wound hygiene interventions will likely enhance infection resolution and wound healing, reduce the requirement for systemic antibiotic therapy, and support antimicrobial stewardship initiatives in wound care.

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.

Contamination Risk During Fecal Management Device Removal: An In vitro, Simulated Clinical Use Study.

Fecal management devices (FMDs) are used to drain and contain fecal matter in incontinent, often acutely or critically ill patients to protect their skin as well as the environment from contamination. However, there is potential for contamination and resultant infection at various stages of FMD use. PURPOSE: This in vitro study was conducted to compare device removal factors and subsequent splash of simulated fecal matter of 3 different designs of FMDs using a simulated rectum. METHODS: A Universal Test Machine was used to automatically measure removal forces (in newtons [N]) and tube extensions as the FMDs were pulled from the simulated rectum by the machine. Splash distance and quantity were measured using a splash-capture cylinder and image analysis software. Each device was tested 3 times. Two-sample t tests were conducted to examine statistical differences in removal forces, removal extensions, and splash areas. RESULTS: The forces required to remove the FMDs from the simulated rectum were significantly lower for the device with a collapsible, donut-shaped retention balloon compared with the devices with a green, foldable, trumpet-shaped retention cuff and a foldable, spherical-shaped retention balloon (12.0 ± 0.3 N vs. 32.6 ± 4.3 N and 34.8 ± 3.1 N, respectively; P <.05). The extensions of the catheter tubing were significantly lower for the device with a collapsible, donut-shaped retention balloon compared with the devices with a green, foldable, trumpet-shaped retention cuff and a foldable, spherical-shaped retention balloon (32.0 ± 7.5 mm vs. 81.3 ± 9.1 mm and 105.2 ± 10.6 mm, respectively; P <.05). Simulated fecal matter was splashed over mean areas of 25.5 ± 16.1 cm2 and 27.3 ± 13.5 cm2 for the devices with a green, foldable, trumpet-shaped retention cuff and a foldable, spherical-shaped retention balloon, respectively; no splash was observed for the device with a collapsible, donut-shaped retention balloon. CONCLUSION: In vitro observations suggest contamination and potential infection risk during FMD removal from the patient are influenced by FMD design. Future in vitro and clinical studies assessing the infectious nature of effluent and methods for containment are warranted.

Perceptions of Wound Biofilm by Wound Care Clinicians.

OBJECTIVE: The aim of this study was to gain a greater understanding of the perceptions of wound biofilm held by wound care clinicians. METHODS: Independent market research was conducted in the United States and Europe via an online questionnaire to understand the knowledge levels of wound biofilm among clinicians. RESULTS: Clinicians from the United States appeared most knowledgeable on the subject of wound biofilm, though there was a wider consensus that biofilm contributes to delayed wound healing. A number of visual and indirect clinical signs for the presence of wound biofilm were commonly listed by all clinicians. In this study, and others, widespread calls for further education on wound biofilm, in addition to anti-biofilm and diagnostic technologies, were made. CONCLUSIONS: This study has contributed to the global call to focus on tackling biofilm for the benefit of wound care patients, caregivers, and health care systems.

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.

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

The objective of this work was to evaluate the safety and effectiveness of a next-generation antimicrobial wound dressing (NGAD; AQUACEL® Ag+ Extra™ dressing) designed to manage exudate, infection and biofilm. Clinicians were requested to evaluate the NGAD within their standard protocol of care for up to 4 weeks, or as long as deemed clinically appropriate, in challenging wounds that were considered to be impeded by suspected biofilm or infection. Baseline information and post-evaluation dressing safety and effectiveness data were recorded using standardised evaluation forms. This data included wound exudate levels, wound bed appearance including suspected biofilm, wound progression, skin health and dressing usage. A total of 112 wounds from 111 patients were included in the evaluations, with a median duration of 12 months, and biofilm was suspected in over half of all wounds (54%). After the introduction of the NGAD, exudate levels had shifted from predominantly high or moderate to low or moderate levels, while biofilm suspicion fell from 54% to 27% of wounds. Wound bed coverage by tissue type was generally shifted from sloughy or suspected biofilm towards predominantly granulation tissue after the inclusion of the NGAD. Stagnant (65%) and deteriorating wounds (27%) were shifted to improved (65%) or healed wounds (13%), while skin health was also reported to have improved in 63% of wounds. High levels of clinician satisfaction with the dressing effectiveness and change frequency were accompanied by a low number of dressing-related adverse events (n = 3; 2·7%) and other negative observations or comments. This clinical user evaluation supports the growing body of evidence that the anti-biofilm technology in the NGAD results in a safe and effective dressing for the management of a variety of challenging wound types.

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.

Management of diabetic foot ulcers: evaluation of case studies.

This article explores local barriers to diabetic foot ulcer healing, and describes the use of a dressing designed to manage exudate, infection and biofilm (AQUACEL® Ag+ dressing (AQAg+)) on recalcitrant diabetic foot ulcers. The authors consider four case studies that demonstrate how managing local barriers to wound healing with antimicrobial and anti-biofilm dressings in protocols of care can improve outcomes for patients.

DEVELOPMENT OF A NEXT-GENERATION ANTIMICROBIAL WOUND DRESSING.

Delayed wound healing due to infection is a burden on healthcare systems, and the patient and caregiver alike. An emerging factor in infection and delayed healing is the presence development of biofilm in wounds. Biofilm is communities of microorganisms, protected by an extracellular matrix of slime in the wound, which can tolerate host defences and applied antimicrobials such as antibiotics or antimicrobial dressings. A growing evidence base exists suggesting that biofilm exists in a majority of chronic wounds, and can be a precursor to infection while causing delayed healing itself. In vivo models have demonstrated that the inflammatory, granulation and epithelialization processes of normal wound healing are impaired by biofilm presence. The challenge in the development of a new antimicrobial wound dressing was to make standard antimicrobial agents more effective against biofilm, and this was answered following extensive biofilm research and testing. A combination of metal chelator, surfactant and pH control displayed highly synergistic anti-biofilm action with 1.2% ionic silver in a carboxymethylcellulose dressing. Its effectiveness was challenged and proven in complex in vitro and in vivo wound biofilm models, followed by clinical safety and performance demonstrations in a 42-patient study and 113 clinical evaluations. Post-market surveillance was conducted on the commercially available dressing, and in a 112-case evaluation, the dressing was shown to effectively manage exudate and suspected biofilm while shifting difficult-to-heal wounds onto healing trajectories, after an average of 4 weeks of new dressing use in otherwise standard wound care protocols. This was accompanied by a low frequency of dressing related adverse events. In a second evaluation, clinical signs of infection and wound dimension data, before and after the evaluations, were also available. Following an average of 5.4 weeks of dressing use, all signs of clinical infection were reduced, from an average frequency of 36% to 21%. An average of 62% wound size reduction was achieved, with 90% of wounds reducing in size and 10 wounds healing completely. The new clinical evidence for this next-generation antimicrobial wound dressing suggests it is safe and effective at managing exudate, infection and biofilm, while it can shift established, stubborn wounds onto healing trajectories. The scientific rationale for this new dressing technology is supported by in vitro and in vivo evidence, so now further comparative, randomized and outcome-based clinical studies are required to fully understand the clinical and economic benefits this new dressing technology can bring.

Epithelial-mesenchymal transition, IP3 receptors and ER-PM junctions: translocation of Ca2+ signalling complexes and regulation of migration.

Disconnection of a cell from its epithelial neighbours and the formation of a mesenchymal phenotype are associated with profound changes in the distribution of cellular components and the formation of new cellular polarity. We observed a dramatic redistribution of inositol trisphosphate receptors (IP3Rs) and stromal interaction molecule 1 (STIM1)-competent endoplasmic reticulum-plasma membrane junctions (ER-PM junctions) when pancreatic ductal adenocarcinoma (PDAC) cells disconnect from their neighbours and undergo individual migration. In cellular monolayers IP3Rs are juxtaposed with tight junctions. When individual cells migrate away from their neighbours IP3Rs preferentially accumulate at the leading edge where they surround focal adhesions. Uncaging of inositol trisphosphate (IP3) resulted in prominent accumulation of paxillin in focal adhesions, highlighting important functional implications of the observed novel structural relationships. ER-PM junctions and STIM1 proteins also migrate to the leading edge and position closely behind the IP3Rs, creating a stratified distribution of Ca(2+) signalling complexes in this region. Importantly, migration of PDAC cells was strongly suppressed by selective inhibition of IP3Rs and store-operated Ca(2+) entry (SOCE), indicating that these mechanisms are functionally required for migration.

Clinician perceptions of wound biofilm.

In wound care today, biofilm is a subject area of great interest and debate. There is an increasing awareness that biofilm exists in the majority of non-healing wounds, and that it is implicated in both recalcitrance and infection. Together with the presence of devitalised host tissue, biofilm is recognised as a component of the wound environment that requires removal to enable wound progression. However, uncertainty exists among wound care practitioners regarding confirmation of the presence of biofilm, and how best to remove biofilm from a non-healing wound. While recent efforts have been taken to assist practitioners in signs and symptoms of wound biofilm, continuing research is required to characterise and confirm wound biofilm. This research was conducted as part of a market research process to better understand the knowledge levels, experiences, clinical awareness and impact of biofilm in wound care, which was undertaken across the USA and Europe. While knowledge levels and experiences vary from country to country, certain wound characteristics were consistently associated with the presence of biofilm.

Intraguild predation leads to genetically based character shifts in the threespine stickleback.

Intraguild predation is a common ecological interaction that occurs when a species preys upon another species with which it competes. The interaction is potentially a mechanism of divergence between intraguild prey (IG-prey) populations, but it is unknown if cases of character shifts in IG-prey are an environmental or evolutionary response. We investigated the genetic basis and inducibility of character shifts in threespine stickleback from lakes with and without prickly sculpin, a benthic intraguild predator (IG-predator). Wild populations of stickleback sympatric with sculpin repeatedly show greater defensive armor and water column height preference. We laboratory-raised stickleback from lakes with and without sculpin, as well as marine stickleback, and found that differences between populations in armor, body shape, and behavior persisted in a common garden. Within the common garden, we raised stickleback half-families from multiple populations in the presence and absence of sculpin. Although the presence of sculpin induced trait changes in the marine stickleback, we did not observe an induced response in the freshwater stickleback. Behavioral and morphological trait differences between freshwater populations thus have a genetic basis and suggest an evolutionary response to intraguild predation.

Clinical Biofilms: A Challenging Frontier in Wound Care.

Significance: Biofilms have been implicated in a variety of wound complications. Recent Advances: Research has confirmed that biofilms form in wounds of patients experiencing delayed healing and may be a precursor to infection. Critical Issues: Research into the strength of this association is still in its infancy. Is biofilm formation a cause of these complications, a step toward them, or a signal that unresolved factors injuring tissue or delaying healing are setting the stage for biofilm formation, infection, and healing delay? To qualify biofilms for use in informing clinical practice decisions, biofilm characteristics supporting those decisions need standardized definitions and valid evidence that they predict or diagnose healing or infection outcomes. Literature searches of relevant terms reviewed biofilm definitions and validation of their role in predicting and diagnosing delayed wound healing or infection. Future Directions: Further research is needed to provide a rapid accurate technique to identify and characterize biofilms in ways that optimize their validity in diagnosing or screening patient risk of infection or delayed healing and to inform clinical decisions. This research will help validate biofilm's capacity to support wound care clinical practice decisions and establish their importance in guiding clinical practice.

Flat clathrin lattices: stable features of the plasma membrane.

Clathrin-mediated endocytosis (CME) is a fundamental property of eukaryotic cells. Classical CME proceeds via the formation of clathrin-coated pits (CCPs) at the plasma membrane, which invaginate to form clathrin-coated vesicles, a process that is well understood. However, clathrin also assembles into flat clathrin lattices (FCLs); these structures remain poorly described, and their contribution to cell biology is unclear. We used quantitative imaging to provide the first comprehensive description of FCLs and explore their influence on plasma membrane organization. Ultrastructural analysis by electron and superresolution microscopy revealed two discrete populations of clathrin structures. CCPs were typified by their sphericity, small size, and homogeneity. FCLs were planar, large, and heterogeneous and present on both the dorsal and ventral surfaces of cells. Live microscopy demonstrated that CCPs are short lived and culminate in a peak of dynamin recruitment, consistent with classical CME. In contrast, FCLs were long lived, with sustained association with dynamin. We investigated the biological relevance of FCLs using the chemokine receptor CCR5 as a model system. Agonist activation leads to sustained recruitment of CCR5 to FCLs. Quantitative molecular imaging indicated that FCLs partitioned receptors at the cell surface. Our observations suggest that FCLs provide stable platforms for the recruitment of endocytic cargo.

The visualization of biofilms in chronic diabetic foot wounds using routine diagnostic microscopy methods.

Diabetic foot wounds are commonly colonised by taxonomically diverse microbial communities and may additionally be infected with specific pathogens. Since biofilms are demonstrably less susceptible to antimicrobial agents than are planktonic bacteria, and may be present in chronic wounds, there is increasing interest in their aetiological role. In the current investigation, the presence of structured microbial assemblages in chronic diabetic foot wounds is demonstrated using several visualization methods. Debridement samples, collected from the foot wounds of diabetic patients, were histologically sectioned and examined using bright-field, fluorescence, and environmental scanning electron microscopy and assessed by quantitative differential viable counting. All samples (n = 26) harboured bioburdens in excess of 5 log10 CFU/g. Microcolonies were identified in 4/4 samples by all three microscopy methods, although bright-field and fluorescence microscopy were more effective at highlighting putative biofilm morphology than ESEM. Results in this pilot study indicate that bacterial microcolonies and putative biofilm matrix can be visualized in chronic wounds using fluorescence microscopy and ESEM, but also using the simple Gram stain.

A two-tier Golgi-based control of organelle size underpins the functional plasticity of endothelial cells.

Weibel-Palade bodies (WPBs), endothelial-specific secretory granules that are central to primary hemostasis and inflammation, occur in dimensions ranging between 0.5 and 5 µm. How their size is determined and whether it has a functional relevance are at present unknown. Here, we provide evidence for a dual role of the Golgi apparatus in controlling the size of these secretory carriers. At the ministack level, cisternae constrain the size of nanostructures ("quanta") of von Willebrand factor (vWF), the main WPB cargo. The ribbon architecture of the Golgi then allows copackaging of a variable number of vWF quanta within the continuous lumen of the trans-Golgi network, thereby generating organelles of different sizes. Reducing the WPB size abates endothelial cell hemostatic function by drastically diminishing platelet recruitment, but, strikingly, the inflammatory response (the endothelial capacity to engage leukocytes) is unaltered. Size can thus confer functional plasticity to an organelle by differentially affecting its activities.

TestSTORM: Simulator for optimizing sample labeling and image acquisition in localization based super-resolution microscopy.

Localization-based super-resolution microscopy image quality depends on several factors such as dye choice and labeling strategy, microscope quality and user-defined parameters such as frame rate and number as well as the image processing algorithm. Experimental optimization of these parameters can be time-consuming and expensive so we present TestSTORM, a simulator that can be used to optimize these steps. TestSTORM users can select from among four different structures with specific patterns, dye and acquisition parameters. Example results are shown and the results of the vesicle pattern are compared with experimental data. Moreover, image stacks can be generated for further evaluation using localization algorithms, offering a tool for further software developments.

Test samples for optimizing STORM super-resolution microscopy.

STORM is a recently developed super-resolution microscopy technique with up to 10 times better resolution than standard fluorescence microscopy techniques. However, as the image is acquired in a very different way than normal, by building up an image molecule-by-molecule, there are some significant challenges for users in trying to optimize their image acquisition. In order to aid this process and gain more insight into how STORM works we present the preparation of 3 test samples and the methodology of acquiring and processing STORM super-resolution images with typical resolutions of between 30-50 nm. By combining the test samples with the use of the freely available rainSTORM processing software it is possible to obtain a great deal of information about image quality and resolution. Using these metrics it is then possible to optimize the imaging procedure from the optics, to sample preparation, dye choice, buffer conditions, and image acquisition settings. We also show examples of some common problems that result in poor image quality, such as lateral drift, where the sample moves during image acquisition and density related problems resulting in the 'mislocalization' phenomenon.