The majority of dermal wounds are colonized with aerobic and anaerobic microorganisms that originate predominantly from mucosal surfaces such as those of the oral cavity and gut. The role and significance of microorganisms in wound healing has been debated for many years. While some experts consider the microbial density to be critical in predicting wound healing and infection, others consider the types of microorganisms to be of greater importance. However, these and other factors such as microbial synergy, the host immune response, and the quality of tissue must be considered collectively in assessing the probability of infection. Debate also exists regarding the value of wound sampling, the types of wounds that should be sampled, and the sampling technique required to generate the most meaningful data. In the laboratory, consideration must be given to the relevance of culturing polymicrobial specimens, the value in identifying one or more microorganisms, and the microorganisms that should be assayed for antibiotic susceptibility. Although appropriate systemic antibiotics are essential for the treatment of deteriorating, clinically infected wounds, debate exists regarding the relevance and use of antibiotics (systemic or topical) and antiseptics (topical) in the treatment of nonhealing wounds that have no clinical signs of infection. In providing a detailed analysis of wound microbiology, together with current opinion and controversies regarding wound assessment and treatment, this review has attempted to capture and address microbiological aspects that are critical to the successful management of microorganisms in wounds.

Wound microbiology and associated approaches to wound management.

Wound healing remains a challenging clinical problem and correct, efficient wound management is essential. Much effort has been focused on wound care with an emphasis on new therapeutic approaches and the development of technologies for acute and chronic wound management. Wound healing involves multiple cell populations, the extracellular matrix and the action of soluble mediators such as growth factors and cytokines. Although the process of healing is continuous, it may be arbitrarily divided into four phases: (i) coagulation and haemostasis; (ii) inflammation; (iii) proliferation; and (iv) wound remodelling with scar tissue formation. The correct approach to wound management may effectively influence the clinical outcome. This review discusses wound classification, the physiology of the wound healing process and the methods used in wound management.

https://journals.sagepub.com/doi/pdf/10.1177/147323000903700531

The wound healing process: an overview of the cellular and molecular mechanisms.

The medical literature describes numerous in vitro and in vivo wound-healing models. The selection of an animal model depends on a number of factors including availability, cost, ease of handling, investigator familiarity, and anatomical/functional similarity to humans. Small mammals are frequently used for wound healing studies, however, these mammals differ from humans in a number of anatomical and physiological ways. Anatomically and physiologically, pig skin is more similar to human skin. The many similarities between man and pig would lead one to believe that the pig should make an excellent animal model for human wound healing. The purpose of this paper is to review the existing literature for evidence of this supposition and determine how well the various models correlate to human wound healing. Studies of wound dressings, topical antimicrobials, and growth factors are examined. Over 180 articles were utilized for this comparative review. Our conclusion is that the porcine model is an excellent tool for the evaluation of therapeutic agents destined for use in human wounds.

The pig as a model for human wound healing

Understanding wound healing today involves much more than simply stating that there are three phases: inflammation, proliferation, and maturation. Wound healing is a complex series of reactions and interactions among cells and "mediators." Each year, new mediators are discovered and our understanding of inflammatory mediators and cellular interactions grows. This article will attempt to provide a concise overview on wound healing and wound management.

Wound healing: an overview.

Chronic wounds are a major healthcare problem costing the United States billions of dollars a year. The American Academy of Dermatology has underscored the significance of wound care in dermatological practice. It is critical for all dermatologists to understand the elements of diagnosis and therapy. We emphasize major aspects of diagnosis and present a simple classification of wound dressings with guidelines for usage and relative cost data. Learning objective After completing this learning activity, participants should be able to diagnose common types of chronic wounds, formulate a therapeutic plan, and describe the major classes of topical therapies and dressings for the chronic wound.

http://www.manukahonning.no/uploads/3/9/6/3/39639435/2008_treating_the_chronic_wound_a_practical_approach_to_the_care_of_nonhealing_wounds_and_wound_care_dressings.pdf

Treating the chronic wound: A practical approach to the care of nonhealing wounds and wound care dressings

The effect of occlusive dressings on collagen synthesis and re-epithelialization in superficial wounds

The Healing of Superficial Skin Wounds Is Stimulated by External Electrical Current

This study was designed to examine the possibility that some occlusive dressings are barriers to wound penetration by pathogenic bacteria. Two common skin pathogens, the nonmotile, Staphylococcus aureus , and the motile, Pseudomonas aeruginosa , were used to challenge dressings placed on partial-thickness wounds in swine. S. aureus was recovered from 100% of air-exposed wounds (log, 5.5 ± 1.1) and from 50% of Op-Site-treated and Vigilon-treated wounds (log, 6.1 ± 1.1). S. aureus was not isolated from DuoDERM-covered wounds, P. aeruginosa was recovered from 100% of air-exposed wounds (log, 5.1 ± 0.5) and 100% of Op-Site-covered and Vigilon-covered wounds (log, 5.8 ± 1.8). P. aeruginosa was not recovered from DuoDERM-covered wounds. These studies lend support to the idea that dressings may protect wounds from invasion by pathogenic bacteria and demonstrate the need to evaluate their bacterial barrier properties in situ.

https://www.jaad.org/article/S0190-9622(85)70091-6/pdf

Occlusive wound dressings to prevent bacterial invasion and wound infection

We studied the effect of 95% DMSO on dermal/epidermal healing and microbiol flora in partial-thickness wounds. Wounds of 0.3 mm were made in the skin of Yorkshire pigs with a keratome and treated daily with either 95% DMSO, water, or they were left untreated. Wounds were excised on Days 2-7 and the dermis was separated from the epidermis. The dermis was assayed for collagen biosynthesis (by measuring the production of [14C]hydroxyproline (HP) and amount of radioactive peptides released after collagenase digestion) and absolute HP (by spectrophotometric analysis). The epidermis was evaluated macroscopically for resurfacing. Aerobic bacteria from unwounded and wounded skin were identified and quantitated. There were no significant differences between treatment groups in HP incorporation or absolute collagen content from Days 2-6 after wounding. HP incorporation in the total protein fractions and in the collagenase digestible fractions were analogous. Collagen biosynthesis was similar in both unwounded, untreated, and unwounded DMSO-treated skin. Epidermal healing did not differ between treatment groups. There were no differences in the number or types of bacteria in wounds between treatment groups. These results indicate that topical DMSO is neither beneficial nor harmful in the healing of superficial wounds.

Patricia M. Mertz

Papers

The effect of occlusive dressings on collagen synthesis and re-epithelialization in superficial wounds

The Healing of Superficial Skin Wounds Is Stimulated by External Electrical Current

Occlusive wound dressings to prevent bacterial invasion and wound infection

Dimethyl sulfoxide (DMSO) does not affect epidermal wound healing.

The effect of a new antimicrobial peptide magainin on pseudomonas aeruginosa proliferation in wounds