Biofilm

By Temple University School of Podiatric Medicine Journal Review Club

Chronic wounds require an increased amount of oxygen to help with cellular function and growth. They often manifest with biofilm, slough, and necrotic tissue, all of which deprive cells of the oxygen they need to perform vital functions. Various forms of debridement are commonly employed to rid wounds of pathological tissues that negatively affect cellular communication and growth. Sharp surgical debridement is most frequently performed by physicians. Continuous diffusion of oxygen (CDO) involves the use of humidified, purified air at 3mL/hour in conjunction with moist wound therapy (MWT) dressing. A previous paper by Niederauer et al. published in 2018 in the Journal of Wound Care, described using CDO for healing DFUs. This study showed that CDO improved the healing rate of DFUs in terms of time, chronicity, and weight-bearing ability when compared to a placebo. Additionally, the previous paper described wound size, chronicity, and adverse events.

Bioburden: Bioburden is the number of microorganisms in a wound, and a high bioburden can cause delayed wound healing.

Biofilm: Biofilms are usually composed of mixed strains of bacteria, fungi, yeasts, algae, microbes, and other cellular debris that adhere to the wound surface.

Epibole: Epibole refers to rolled or curled-under closed wound edges. These rolled edges are thickened epidermis that may be callused, dry, scaly, and/or hyperkeratotic. When epibole is present in a wound, it signals to the body that the wound has healed, even though the wound remains open. Epibole must be resolved to allow the wound to close.

Delayed wound healing occurs in various wound types and in patients with significant comorbidities. Hard-to-heal wounds have proven to be a challenging and worldwide crisis resulting in high financial burdens.

Biofilms are found in the majority of chronic wounds and pose a critical health threat, causing nearly 80% of refractory nosocomial infections. They also have a damaging virulence mechanism, which induces resistance to antimicrobials and evasion from the host’s immune system. Over 90% of chronic wounds contain bacteria and fungi living within a biofilm construct. Biofilms have been reported as major contributing factors to a multitude of chronic inflammatory diseases. Given the resistance of the bacteria, biofilms increase the risk of infection and cost the health care system millions of dollars annually. Clinicians should have practical knowledge of the role and impact that biofilms play in impeding chronic wounds, thus leading to risks of complications such as infection.

Wound debridement is a critical strategy in treating hard-to-heal wounds. It is a process that expedites healing by removing necrotic tissue, non-viable tissue, and foreign material. It can also be used to manage biofilm to prevent infection. Debriding a wound exposes the healthy underlying tissue to promote healing. There are several methods of debridement. Determining the best option will depend on the health care setting as well as the characteristics of the wound being treated.

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

Wound chronicity is defined as any wound that is physiologically impaired due to a disruption in the wound healing cascade: 1) hemostasis, 2) inflammation, 3) proliferation, and 4) maturation/remodeling. To effectively manage chronic wounds, we must understand the normal healing process and wound bed preparation (WBP). Wound chronicity can occur due to impaired angiogenesis, innervation, or cellular migration. The presence of biofilm and infection are the most common causes of delayed healing.

By the WoundSource Editors

Wound chronicity is an ongoing challenge for patients and health care professionals around the globe. An astonishing 4.5 million people in the United States experience lower extremity wound chronicity, while an estimated 1% are affected in the Western population with all types of chronic wounds. The cascade of wound healing does not always follow suit in an orderly fashion of hemostasis, inflammation, proliferation, and remodeling.

By the WoundSource Editors

Necrotic wounds are characterized by devitalized, or dead, tissue. Necrosis may be caused by malignancy, infection, trauma, ischemia, inflammation, or exposure to toxins. It may also be caused by improper care of an existing wound site. Devitalized tissue has no blood supply, and its presence prevents wound healing. It is necessary for necrotic tissue to be removed to allow wound healing to occur.