Clinical management of chronic wound infections: The battle against biofilm.

Bacteria constitute the most abundant life form on earth, of which the majority exist in a protective biofilm state. Since the 1980s, we have learned much about the role of biofilm in human chronic infections, with associated global healthcare costs recently estimated at ~$386 billion. Chronic wound infection is a prominent biofilm-induced condition that is characterised by persistent inflammation and associated host tissue destruction, and clinical signs that are distinct from signs of acute wound infection.

Assessing Biofilm at the Bedside: Exploring Reliable Accessible Biofilm Detection Methods.

Introduction: Biofilm is linked through a variety of mechanisms to the pathogenesis of chronic wounds. However, accurate biofilm detection is challenging, demanding highly specialized and technically complex methods rendering it unapplicable for most clinical settings. This study evaluated promising methods of bedside biofilm localization, fluorescence imaging of wound bacterial loads, and biofilm blotting by comparing their performance against validation scanning electron microscopy (SEM).

Use of fluorescence imaging to optimize location of tissue sampling in hard-to-heal wounds.

Introduction: Wound microflora in hard-to-heal wounds is invariably complex and diverse. Determining the interfering organisms(s) is therefore challenging. Tissue sampling, particularly in large wounds, is subjective and, when performed, might involve swabbing or biopsy of several locations.

'Granulitis': defining a common, biofilm-induced, hyperinflammatory wound pathology.

The hard-to-heal (chronic) wound condition, now believed to be inextricably linked to the presence of microbial biofilm, has posed challenges in translating scientific understanding to clinical practice in recent decades. During this time, multiple descriptive terms of the wound pathology have been described, including critical colonisation, biofilm infection and inflammatory stasis. However, the absence of naming this disease state as a specifically identified condition that is tangible to treat has led to some confusion and delay in possible therapeutic approaches.

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.

Acute and chronic wound infections: microbiological, immunological, clinical and therapeutic distinctions.

Wound infection is a complex pathology that may manifest either as a rapid onset acute condition, or as a prolonged chronic condition. Although systemic antibiotic therapy is often appropriate and necessary for acute wound infections, it is often used inappropriately, excessively and unsuccessfully in chronic wound infections. Overuse of antibiotics in chronic (hard-to-heal) wound management contributes to antibiotic resistance.

Are Semi-Quantitative Clinical Cultures Inadequate? Comparison to Quantitative Analysis of 1053 Bacterial Isolates from 350 Wounds.

Early awareness and management of bacterial burden and biofilm is essential to wound healing. Semi-quantitative analysis of swab or biopsy samples is a relatively simple method for measuring wound microbial load. The accuracy of semi-quantitative culture analysis was compared to 'gold standard' quantitative culture analysis using 428 tissue biopsies from 350 chronic wounds.

Biofilm exacerbates antibiotic resistance: Is this a current oversight in antimicrobial stewardship?

Objective: To raise awareness of the role of environmental biofilm in the emergence and spread of antibiotic resistance and its consideration in antimicrobial stewardship.

Background: Antibiotic resistance is a major threat to public health. Overuse of antibiotics, increased international travel, and genetic promiscuity amongst bacteria have contributed to antibiotic resistance, and global containment efforts have so far met with limited success.

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.

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

Unlabelled: 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.

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.

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.

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).

Antibiotic resistance and biofilm tolerance: a combined threat in the treatment of chronic infections.

Since the introduction of antibiotics into human medicine in the 1940's, antibiotic resistance has emerged at an alarming rate and is now a major threat to public health. This problem is amplified by pathogenic bacteria existing most commonly in biofilm form, creating additional bacterial tolerance to antimicrobial agents. Biofilm is now considered to be a primary cause of chronic infection, and antibiotic-resistant bacteria are prevalent in biofilm form.

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 study aimed to compare its effectiveness against various existing wound dressings and examine its mode of action.

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.

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.

Enzyme-responsive polymers for microbial infection detection.

There is a pressing need for point-of-care diagnostics indicating early stages of infection. Polymers can respond to enzymes secreted by microorganisms or released by the human immune system. This provokes either a direct color reaction or release of dyes, allowing early-stage detection of wound infections and contamination of medical devices.

Safety and performance evaluation of a next-generation antimicrobial dressing in patients with chronic venous leg ulcers.

The objective of this study was to investigate the safety and performance of AQUACEL™ Ag+ dressing, a wound dressing containing a combination of anti-biofilm and antimicrobial agents, in the management of chronic wounds. Patients (n = 42) with venous leg ulcers exhibiting signs of clinical infection were treated for 4 weeks with AQUACEL™ Ag+ dressing, followed by management with AQUACEL™ wound dressings for 4 weeks. Wound progression, wound size, ulcer pain and clinical evolution of the wound were assessed for up to 8 weeks.

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.

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.

In vitro antimicrobial efficacy of a silver-containing wound dressing against mycobacteria associated with atypical skin ulcers.

Mycobacterium ulcerans, the etiological agent in Buruli and related ulcers, is a major threat to public health in many tropical countries. Recommended treatment that is accessible and affordable for affected individuals includes surgical debridement and combination antibiotics. The potential benefits in the use of antimicrobial wound dressings has not been demonstrated to date, and consequently the efficacy of a silver-containing absorbent dressing was investigated against a pathogenic wound mycobacterium using stringent in vitro models.

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.