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.

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.

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.

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.

Biofilm delays wound healing: A review of the evidence.

Biofilm is the predominant mode of life for bacteria and today it is implicated in numerous human diseases. A growing body of scientific and clinical evidence now exists regarding the presence of biofilm in wounds. This review summarizes the clinical experiences and in vivo evidence that implicate biofilm in delayed wound healing. The various mechanisms by which biofilm may impede healing are highlighted, including impaired epithelialization and granulation tissue formation, and reduced susceptibilities to antimicrobial agents and host defenses. Strategies to manage biofilm and encourage progression to wound healing are discussed; these include debridement and appropriate antimicrobial therapies which may be improved upon in the future with the emergence of anti-biofilm technologies.