Bacterial Contribution in Chronicity of Wounds

Abstract

A wound is damage of a tissue usually caused by laceration of a membrane, generally the skin. Wound healing is accomplished in three stages in healthy individuals, including inflammatory, proliferative, and remodeling stages. Healing of wounds normally starts from the inflammatory phase and ends up in the remodeling phase, but chronic wounds remain in an inflammatory stage and do not show progression due to some specific reasons. Chronic wounds are classified in different categories, such as diabetic foot ulcer (DFU), venous leg ulcers (VLU) and pressure ulcer (PU), surgical site infection (SSI), abscess, or trauma ulcers. Globally, the incidence rate of DFU is 1-4 % and prevalence rate is 5.3-10.5 %. However, colonization of pathogenic bacteria at the wound site is associated with wound chronicity. Most chronic wounds contain more than one bacterial species and produce a synergetic effect that results in previously non-virulent bacterial species becoming virulent and causing damage to the host. While investigating bacterial diversity in chronic wounds, Staphylococcus, Pseudomonas, Peptoniphilus, Enterobacter, Stenotrophomonas, Finegoldia, and Serratia were found most frequently in chronic wounds. Recently, it has been observed that bacteria in chronic wounds develop biofilms that contribute to a delay in healing. In a mature biofilm, bacteria grow slowly due to deficiency of nutrients that results in the resistance of bacteria to antibiotics. The present review reflects the reasons why acute wounds become chronic. Interesting findings include the bacterial load, which forms biofilms and shows high-level resistance toward antibiotics, which is a threat to human health in general and particularly to some patients who have acute wounds.

Antimicrobial photodynamic therapy in skin wound healing: A systematic review of animal studies

“…It involves three somewhat overlapping sequential phases, namely, the inflammatory, proliferative, and remodelling phases. Many cells, molecules, and biochemical events are involved in this process . During the inflammatory phase, immune cells in the wound bed (eg, neutrophils and macrophages) release a variety of growth factors and chemokines to remove contaminating microbes .…”

Antimicrobial peptides secreted by equine mesenchymal stromal cells inhibit the growth of bacteria commonly found in skin wounds

“…Chronic wounds are classified into different categories and are caused by a variety of insults. A common feature of chronic wounds, regardless of initial cause, is colonization by pathogenic bacteria, which leads to an inflammatory host response and delayed wound healing [4, 5]. Chronic wounds typically contain a diversity of bacterial species that may interact to form matrices on wound surfaces called biofilms.…”

“…Like humans, horses suffer from naturally occurring chronic wounds [16, 17] and bacterial infection of horse wounds delays the normal healing process by prolonging inflammation, reducing resident skin cell migration, and disrupting extracellular matrix formation [5, 18]. …”

Pseudomonas aeruginosa as a Powerful Biofilm Producer and Positive Action of Amikacin Against Isolates From Chronic Wounds

“…Pseudomonas aeruginosa is a Gram-negative and rodshaped opportunistic pathogen that is a major causative microorganism in wound infections, delaying the wound healing process. such as diabetic foot ulcer (DFU), venous leg ulcers (VLU), pressure ulcer (PU), surgical site infection (SSI), and abscess or trauma ulcers (5). These types of infections are prolonged and become chronic because of bacterial contribution to chronic wounds, on which biofilms develop and increase the normal period of healing (6,7).…”