Biofilm

By Temple University School of Podiatric Medicine Journal Review Club

An appropriate timeline to initiate biofilm-based wound care (BBWC) has been a topic of question since the incorporation of biofilm therapy was introduced. In hard-to-heal delayed wounds, it is largely agreed upon that biofilms are a significant barrier to healing, and that removal is essential. By definition, hard-to-heal wounds are wounds that have failed to respond to evidence-based standard of care and contain biofilm. Biofilms are polymicrobial communities residing in an extracellular matrix produced by bacteria, which is well-hydrated and resistant against antimicrobial agents and host defenses. Biofilm can form within hours, can reach maturity within 48-72 hours, and has the ability to regrow within 24-48 hours. A first critical step to BBWC is debridement, though it requires additional suppression methods, as well as considerations of a patient’s risk factors. Risk factors include peripheral vascular disease, infection, diabetes, and pressure off-loading, which encourage biofilm development by delaying wound healing. Risks and costs with early BBWC are most likely less than those associated with biofilm-related wound complications. Thus, in March 2019, a panel of nine experts met in London for an Advisory Board Meeting, where they developed solutions to barriers preventing early BBWC and methods of appropriate “wound hygiene” for all health professionals. They reconvened in the summer of 2019 to create a clinical consensus document published in the Journal of Wound Care supported by ConvaTec Limited.

By the WoundSource Editors

Wound healing is a complex biological process that involves a sequence of molecular and cellular events to restore damaged tissue. These events occur within the extracellular matrix, a complex three-dimensional acellular environment that is present within all tissue and essential for life. Remodeling within this extracellular matrix is necessary for tissue repair throughout the wound healing process, including during the inflammatory phase.

By the WoundSource Editors

All wounds are complex non-sterile environments, often requiring a succession of intersecting phases of wound healing to repair completely. When epithelial tissue is compromised by a wound, contamination by common skin surface microbes may result in infection or the formation of a biofilm that impedes healing. Although systemic antibiotics are necessary for treating clinically infected wounds, the use of antibiotics and antiseptics in non-healing, non-infected wounds is debated.

By the WoundSource Editors

Antimicrobial dressings: Dressings that contain substances with antimicrobial properties, such as silver, chlorhexidine, honey, or iodine. These dressings can be effective in reducing bioburden and promoting healing.

Antimicrobial stewardship: Collective measures that are taken to slow the evolution of multidrug-resistant organisms.

Bacterial resistance: The capacity of bacteria to withstand the effects of antibiotics that are meant to kill them; this term is commonly used interchangeably with antibiotic resistance.

Temple University School of Podiatric Medicine Journal Review Club

Delayed healing in diabetic foot ulcers (DFUs) is the result of the polymicrobial structures of DFUs and the buildup of biofilms. Wound debridement is an essential part of wound bed preparation (WBP) that helps to remove bacteria and allow the body to continue the healing process. Although sharp debridement is the most common technique used for DFUs, it has many limitations, including contraindications in patients with poor vascular status, the need for an operating room, and the requirement for specific surgeon skills. There is also the potential for extensive damage to the wound bed with exposed bone because of obstruction of the view from biofilm formation. The use of an ultrasound-assisted wound (UAW) debridement device aims to disrupt the formation of biofilms and stimulate wound granulation, thus allowing for the wound to have a healthy environment in which to heal. This study evaluated the clinical and microbiological impact of using UAW debridement devices in individuals with neuroischemic DFUs.

By the WoundSource Editors

Caseous necrosis: Caseous necrosis is found in tuberculosis, syphilis, and some fungal diseases. It forms in response to intracellular pathogens, such as mycobacteria, and can also be found in association with granulomas. With this type of cell death, the tissue assumes a cheese-like appearance.

Clostridium difficile: Also referred to C. diff, this bacterium can cause symptoms ranging from diarrhea to life-threatening inflammation of the colon. On a lesion, semihard nodules may be found, in which case lymph node tuberculosis may be present.

Complex wounds: Wounds that have one or more complicating factor, such as exudate, infection, comorbidity, or polypharmacy. They can be acute or chronic wounds that defy cure with conventional therapies. Treating complex wounds generally requires a multidisciplinary approach.

By the WoundSource Editors

Biofilm: this term is frequently used in the wound care space, but biofilm continues to be largely undertreated in wound care. What do the bedside nurse or clinician need to know about biofilm? Should clinicians care less about biofilm on a maintenance or palliative wound versus a wound they are actively trying to heal? Let's address these questions and get to the root of the biofilm in managing complex wound cases.

By Gregory Schultz, PhD

In my recent WoundSource webinar on the assessment and treatment of chronic wounds and biofilms, I discussed the pathogenesis of chronic wounds and offered a biofilm-based wound care protocol to promote healing.

by the WoundSource Editors

Advancements in molecular microbiology, microscopy technology, and techniques for study of bacteria have increased the ability to identify the existence of biofilms, but there still remains the unknown, such as differentiating between planktonic bacteria and biofilm.¹ Chronic non-healing wounds harbor bacteria across the wound etiology classification.^2–4 Malone et al. determined that the prevalence of biofilms in chronic wounds was 78.2% (confidence interval, 61.6–89, P < 0.002).² The development of biofilms moves through a common pattern: attachment, microcolony formation, maturation, and dispersion. The initial attachment is reversible, but the attachment becomes stronger as cells multiply and change their gene expressions. This cell communication process is referred to as quorum sensing, allowing cells to survive.

By the WoundSource Editors

Wound biofilms not only impede healing but also increase the risk of infection. It is essential that wound biofilms be addressed and treated in a prompt, consistent manner. Biofilms have been an ongoing challenge because of the majority of resistant bacteria. Research in antibiofilm technology continues to grow, and it is essential to keep up on the most recent evidenced-based practice literature for improving patients’ outcomes.