Occlusive bandaging of wounds with decreased circulation promotes growth of anaerobic bacteria and necrosis: case report

A methacrylated pullulan hydrogel incorporating phycocyanin-functionalized copper sulfide nanoparticles for photothermal antibacterial therapy and improved wound healing

Bacteria-associated wound infections impose a significant burden on patients and healthcare systems. Consequently, there is an urgent need to develop a novel multifunctional antibiotic-free dressing that can effectively prevent wound infections and promote healing. In this study, a multifunctional hydrogel (PulMA/CuS@PC) was synthesized by encapsulating phycocyanin-Functionalized copper sulfide nanoparticles (CuS@PC) in photo-crosslinkable methacrylated pullulan (PluMA), exhibiting photothermal antibacterial properties and enhanced wound healing capabilities. The PulMA/CuS@PC hydrogel exhibits excellent mechanical properties, favorable swelling ability, good biocompatibility, and effective photothermal antibacterial activity. The incorporation of CuS@PC NPs significantly enhances the hydrogel's photothermal antibacterial efficacy against Escherichia coli and Staphylococcus aureus. Furthermore, the PulMA/CuS@PC hydrogel demonstrated substantial wound healing capability in a mouse model of full-thickness skin infection. This was evidenced by a marked reduction in inflammatory response as well as notable improvements in both wound healing and collagen deposition. This study underscores the potential clinical application of the developed multifunctional PulMA/CuS@PC hydrogel as an innovative wound dressing designed to prevent infection while facilitating skin regeneration.

Bactogram: Spatial Analysis of Bacterial Colonisation in Epidermal Wounds

Skin barrier damage and subsequent development of harmful microbiota contribute to conditions such as wound infections, atopic dermatitis and chronic wounds, which impact millions of people globally and pose a significant economic burden on healthcare systems. Established microbial sampling methods, such as swabs and tissue biopsies, provide limited information on the spatial distribution of bacteria. We here describe a new method that produces a visual map of the distribution of cultivable bacteria, denoted 'Bactogram', across the whole wound and surrounding skin, suitable for image-based quantification. As part of an exploratory endpoint in a clinical trial we applied the Bactogram method to 48 suction blister wounds in 24 healthy volunteers. Bacteria developed in all wounds, predominantly on the skin under the dressing and near wound edges. Two quantification methods, based on visual scoring and image analysis, demonstrated high inter-, and intra-rater agreement and were used to characterise bacterial re-colonisation during epidermal wound healing. We also demonstrated proof of concept that the method can be used with chromogenic agar to enable spatial identification of pathogenic bacterial species, such as Staphylococcus aureus. In conclusion, this study introduces a simple method for sampling bacteria over large areas and generating a bacterial map that can identify spatial variations in bacterial composition and abundance in skin and wound conditions. Trial Registration: ClinicalTrials.gov identifier: NCT05378997.

Does the Application of a Semiocclusive Dressing Alter the Microflora of Healthy Intact Skin on the Foot?

BACKGROUND

The skin on human feet presents unique environments for the proliferation of potentially pathogenic commensals. This study examined microflora changes on healthy intact skin under a semiocclusive dressing on the medial longitudinal arch of the foot to determine changes in growth, distribution, and frequency of microflora under the dressing.

METHODS

Nine human participants wore a low-adherent, absorbent, semiocclusive dressing on the medial longitudinal arch of the left foot for 2 weeks. An identical location on the right foot was swabbed and used as a control. Each foot was swabbed at baseline, week 1, and week 2. The swabs were cultured for 48 hours. Visual identification, Gram staining, DNase test agar, and a latex slide agglutination test were used to identify genera and species.

RESULTS

Microflora growth was categorized as scant (0-10 colony-forming units [CFU]), light (11-50 CFU), moderate (51-100 CFU), or heavy (>100 CFU). Scant and light growth decreased and moderate and heavy growth increased under the dressing compared with the control. Seven different genera of bacteria were identified. Coagulase-negative Staphylococcus spp appeared most frequently, followed by Corynebacterium spp.

CONCLUSIONS

Changes in microflora distribution, frequency, and growth were found under the dressing, supporting historical studies. Microflora changes were identified as an increase in bioburden and reduction in diversity. The application of similar methods, using more sophisticated identification and analysis techniques and a variety of dressings, could lead to a better understanding of bacterial and fungal growth under dressings, informing better dressing selection to assist the healing process of wounds and prevent infection.

The Benefits Of Occlusive Dressings In Wound Healing

There are several types of wounds with their own healing properties. The latest innovation in wound management by using occlusive dressings can prevent infections, improve healing time and patient’s comfort. Occlusive dressings are often used as an immediate wound hygiene control and also prevent blood loss until debridement is performed. They are used to protect wounds and surrounding tissue from pathogens and other harmful materials. A good cover depends on the condition around the wound, the person's skills, and the injury's nature. In this article, we provide an insight into the types of polymer materials used clinically in wound dressing and underlying mechanisms between the biomaterial dressings and the body tissue.