Biofilm and Infected Wounds

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.

By Charles P. Buscemi, PhD, APRN, CWCN and Arturo Gonzalez, DNP, APRN, ANP-BC, CWCN-AP

Urinary catheters serve several purposes, including monitoring urine output, relieving urinary retention, and facilitating diagnosis of disease in the lower urinary tract. These catheters can be inserted easily and are universally available, which usually results in their continued and indiscriminate usage. Urinary catheters can be indwelling or external-condom types. The indwelling catheter can be either a suprapubic or a urethral catheter. The external catheter provides a safe alternative to an indwelling catheter for patients having urinary incontinence (UI). It comprises a sheath surrounding the penis with a tube situated at the tip linked to a collection bag. Conversely, the condom catheter seems an attractive option for patients with UI. About 40% of condom catheter users have urinary tract infections. Moreover, 15% of condom catheter users have necrosis, ulceration, inflammation, and constriction of the penile skin. There is also an additional risk of urine leakage and condom detachment. Furthermore, the use of the external catheter requires significant nursing time. Overall, the condom catheter cannot be satisfactorily used for managing UI; nevertheless, it is useful for the non-invasive measurement of bladder pressure.

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.

Vulnerable skin within the skin microclimate is caused by a multitude of factors that are often aggravated by one another. Urine and feces, for example, have a negative impact on the skin as a result of the microorganisms and enzymes they contain. These factors break down the skin barrier and cause inflammation through the release of cytokines that trigger an immune response leading to symptoms of dermatitis (i.e., moisture-associated skin damage [MASD]). Incontinence-associated dermatitis (IAD) is one type of MASD, and the external factors that contribute to IAD include microclimate (water, temperature, pH), mechanical forces (friction, pressure, shear), and biochemical factors (fungi, irritants, bacteria, enzymes).

Antibiotic resistance is a growing health threat, not just in the United States, but throughout the world. Health care professionals are facing problems with antibiotic resistance, as well as with resistance to other antimicrobial agents. The Centers for Disease Control and Prevention (CDC) noted in 2019 that “more than 2.8 million antibiotic-resistant infections occur in the United States (US) each year, and more than 35,000 people die as a result.” The CDC lists 18 current threats, with three on the watch list as emerging causes of antibiotic resistance. Many of the bacteria on this threat list are found in chronically stalled wounds. Therefore, wound clinicians must be good stewards of antimicrobial treatments to prevent contributing to an already worsening problem.

Treatment of chronic and complex wounds complicated by biofilm formed by pathogens remains a tremendous challenge for the health care industry. Recent increases in infections mediated by drug-resistant bacterial and fungal pathogens highlight the need for new antimicrobial therapies. The application of topical agents with antimicrobial and antiseptic properties is gaining traction as an alternative to antibiotic prescriptions.

Antibiosis: The biological relationship between two organisms in which one living organism kills another to ensure its existence.

Antimicrobial resistance: The process that occurs when bacteria, fungi, and parasites (microorganisms) change over time and no longer respond to antimicrobial medications. This resistance makes it more difficult to treat infections and increases the risk of spreading diseases that result in severe illness and death.

Antimicrobial stewardship plan: An antimicrobial stewardship plan should seek to prevent wound infection in the first place and should promote ideal antibiotic use in clinically infected patients while also preventing use of antibiotics in non-infected patients.