Biofilm

By the WoundSource Editors

The process of wound healing ideally progresses from inflammation to epithelialization and, finally, remodeling. If at any point bacterial (or fungal) colonization becomes prominent, the process of wound healing is disrupted. The creation of biofilm is a microbial defense mechanism that stalls the trajectory of healthy wound healing and can contribute to the development of a chronic wound. It is estimated that 90% of chronic wounds and 6% of acute wounds contain biofilms generated by microbes. Epidemiologically, chronic wounds impact 2% of the entire US population. Because of this large impact, knowledge of proper wound healing and use of clinical tools to assist the wound healing process are essential.

Holly Hovan, MSN, GERO-BC, APRN, CWOCN-AP

Standards of care and evidence-based guidelines should lead our wound care practice to ensure the best possible outcomes for our patients. There are often prewritten algorithms or first- and second-line therapies, along with outlined treatment plans and guidelines established based on evidence. These guidelines can be adjusted to meet each patient’s specific needs.

It is well known that chronic and hard-to-heal wounds have created a global crisis. Delayed healing in these wounds is often associated with biofilm, and antimicrobial dressings can be effective in managing bioburden in chronic wounds. For the use of antimicrobial advanced wound care dressings to be successful in chronic wound care, however, clinicians must have practical knowledge of dressing formats and options, dressing indications and applications, the principles of antimicrobial stewardship, and care planning for specific wound types.

Wounds typically heal in four sequential but overlapping phases — hemostasis, inflammatory, proliferative and remodeling — ultimately leading to tissue regeneration. Healing sometimes stalls for various reasons, a key one being extensive inflammation, which disrupts the normal cascade of healing and leads to chronic and hard-to-heal wounds. A vicious cycle of ongoing inflammation, pain and poor quality of life often follows. Understanding how to break this cycle is essential for wound care clinicians who want to optimize healing outcomes and patient quality of life.

Wound healing can stall for a number of reasons. Wounds that have not healed or significantly reduced in size after four to six weeks are considered chronic. They are characterized by a multitude of impeding factors including biofilm, excess matrix metalloproteinases (MMPs) and extracellular matrix degradation, inflammation, fibrosis, unresponsive keratinocytes and fibroblasts, and atypical growth factor signaling.

Biofilm: Colonies of multiphenotype, free-floating bacteria that secrete a polysaccharide matrix that protects the bacteria from immune response and antibiotics.

Chronic wounds: Wounds that stall in the inflammation phase and fail to progress toward healing within 3 months are considered chronic or hard to heal.

Continuous inflammation: When wound healing becomes stalled in the inflammatory phase because of the presence of bacteria and their endotoxins, the wound is unable to move out of the inflammatory phase and into the repair phase.

As scientists and researchers have delved deeper into the causes of wounds and wound chronicity, matrix metalloproteinases, or MMPs, have come into sharper focus. MMPs are not just present in chronic wounds — they also play an essential role in acute wounds.

An injury to the human body initiates a wound healing chain reaction that occurs in four sequential but overlapping phases: hemostasis, inflammatory, proliferative and maturation. This post focuses on the second (inflammatory) phase, which begins after blood flow stops (i.e., hemostasis) and defender white blood cells, or leukocytes, migrate to the site of the injury — a process known as chemotaxis.

Anoxia: A condition marked by the absence of oxygen reaching the tissues. It differs from hypoxia, in which there is a decrease in the oxygen levels to tissue.

Biocide tolerance: Demonstrating a tolerance to substances that destroy living things, such as bacteria. The initial stage in the life of biofilm can become biocide tolerant within 12 hours.

Calcium alginate: A water-insoluble, gelatinous substance that is highly absorbent. Dressings with calcium alginate can help to maintain a moist healing environment.

Wound healing is often accompanied by bacterial infection. Many clinicians use antibiotics to treat wound infections. However, the overreliance on antibiotics is becoming an increasing concern for many global health organizations because it contributes to widespread antibiotic resistance. Excessive use of synthetic antibiotics leads to drug resistance, which poses a substantial threat to human health.