Imino-quaternized chitosan/chitosan nanofibers loaded with norfloxacin as potential bandages for wound healing

Due to the critical need for effective wound dressings for the management of burn injuries, this paper focuses on addressing key gaps in infection prevention and control. The study aims to develop advanced nanofibrous dressings based on quaternized chitosan/chitosan, loaded with norfloxacin and modified with 2-formylphenylboronic acid to enhance antimicrobial and antioxidant activity and promote healing. The materials combine beneficial properties of chitosan/quaternized chitosan, such as biocompatibility, biodegradability, and antimicrobial activity. The characterization was performed from structural (NMR, FTIR, UV-Vis spectroscopy and thermogravimetric analysis), morphological (SEM, water vapor sorption) and supramolecular points of view (X-Ray Diffraction and Polarized Microscopy). Essential properties for wound dressings were evaluated and proved excellent performances, such as Young's modulus up to 1250 MPa, swelling capacity till 6 g/g, radical scavenging activity of 70 % and enzymatic degradability till 53 % in 21 days. The fibers presented antibacterial properties, reflected by high inhibition zones against Escherichia coli (40 mm) and Staphylococcus aureus (34 mm) and antifungal activity against Candida glabrata (15 mm). Preliminary studies demonstrated the in vitro safety of the materials on Human Gingival Fibroblasts, while in vivo experiments on Wistar rats confirmed the biocompatibility of the materials, emphasizing their potential as effective wound dressings for burns.

Harnessing Nature's Power: Plant and Polymeric-Based Antibacterials as Potential Therapeutics for Infectious Skin Wound Healing

This comprehensive review explores the potential of plant- and biopolymeric-based antibacterials as innovative therapeutic agents for infectious skin wound healing. By researching the antibacterial properties of various plants, the review highlights their application in skin tissue engineering. Beyond reviewing antibacterial plant extracts, the article delves into the limitations these natural compounds face, such as hydrophilicity, drug release rates, cell attachment, and scaffold stability when integrated into tissue engineering constructs. The review also emphasizes the role of biopolymeric materials, hydrogel optimization, and crosslinkers to improve scaffold performance. This review provides a roadmap for future research by addressing critical factors in scaffold construction. In the end, it aims to guide the development of more effective wound dressings and tissue scaffolds, combining the natural power of plants with advanced biopolymeric materials for enhanced wound healing therapies.

Novel Magnesium- and Silver-Loaded Dressing Promotes Tissue Regeneration in Cutaneous Wounds

Wound healing is a dynamic process involving a complex interaction between many cells and mediators. Magnesium (Mg) is an essential element for cell stabilization. Mg was reported to stimulate the proliferation and migration of endothelial cells in angiogenesis in vitro. However, the function of Mg in wound healing is not known. We observed that the expression level of Mg in human wound tissue fluid was only 10% of that found in human blood serum. To confirm whether Mg is a suitable wound dressing material, we fabricated a Mg- or Mg-silver (Ag)-based polyethylene dressing to study its effect on wound healing. We observed that Mg and Ag were stably preserved in the constructed material and were able to be rapidly released in the moist environment. We also observed that the Mg-based dressing had good cellular compatibility without harmful extractables. Furthermore, Mg enhanced the antibacterial activity of Ag. In line with the observed increase in fibroblast migration in vitro, the Mg-Ag-based dressing improved acute and chronic wound repairs via an increase in neovascularization and basal cell proliferation. The present results show that a Mg-Ag-based coating can be manufactured as an optimal dressing for adjuvant wound therapy.

Giant Parotid Abscess With Significant Skin Necrosis: A Case Report

Poor blood glucose control is a common predisposing factor for parotid abscesses; however, extensive skin necrosis secondary to parotid abscesses has rarely been reported. In this article, we present the case of a 70-year-old man with poor glycemic control admitted to our hospital with swelling, congestion, and pain in the right parotid region that had gradually increased over 15 days prior to presentation. Based on the clinical, imaging, and laboratory findings, the patient was diagnosed with a giant parotid abscess with extensive skin necrosis caused by Klebsiella pneumoniae. The abscess responded poorly to long-term treatment with intravenous broad-spectrum antibiotics, and the patient underwent daily Bacillus exchange with blood glucose level management and electrolyte monitoring via routine blood tests. At the 3 month follow-up, complete resolution of the right parotid gland abscess and skin rupture was observed.

Suprathel® or Mepilex® Ag for treatment of partial thickness burns in children: A case control study

AIM

The study aim was to investigate if Suprathel® can be an adequate alternative to Mepilex® Ag for the treatment of partial-thickness scalds in children.

METHODS

A retrospective study including 58 children admitted to The Burn Centre in Linköping, Sweden between year 2015 and 2022. Of the 58 children, 30 were dressed with Suprathel ® and 28 with Mepilex ® Ag. Outcomes investigated were healing time, burn wound infection (BWI), need for operations and number of dressing changes.

RESULTS

We found no significant differences in any of the outcomes. In the Suprathel ® group 17 children and in the Mepilex ® Ag group 15 children were healed within 14 days. Ten children from each group received antibiotics for suspected BWI and two from each group underwent an operation with skin grafting. Each group had on median four dressing changes.

CONCLUSIONS

Two different treatments were compared for children with partial-thickness scalds, and the data indicates that similar results are received with both dressings.

Treatment of experimentally induced partial-thickness burns in rats with different silver-impregnated dressings

PURPOSE

To evaluate the morphometric, macroscopic and microscopic aspects of experimentally induced partial-thickness burns in rats treated with different silver-based dressings.

METHODS

Wistar rats were used, divided into six treatments: saline (NaCl 0.9%); silver sulfadiazine 1%; Silvercel; Mepilex Ag; Aquacel Ag and Acticoat. The animals were monitored daily and euthanized at 7, 14 and 30 days after injury induction (DAI).

RESULTS

At 7 DAI, necrosis/crust was greater in control, silver sulfadiazine and Mepilex Ag treatments, granulation tissue was induced by Aquacel Ag, polymorphonuclear infiltrate (PMN) infiltration was intensified by Mepilex Ag; mononuclear infiltrate (MN) infiltration and angiogenesis were increased by Silvercel. At 14 DAI, hemorrhage was decreased by Silvercel and Mepilex Ag, PMN infiltration increased by Acticoat. At 30 DAI, angiogenesis was greater in the Acticoat treatment and fibroblasts were increased by Acticoat and Mepilex Ag. Collagen was induced at 14 DAI by silver sulfadiazine and Aquacel Ag and, at 30 DAI, by silver sulfadiazine and Silvercel treatments.

CONCLUSIONS

Silvercel and Acticoat presented better results than the other products. However, all the dressings were better than the control at some point during the process, and may contribute to the healing of partial thickness burns. Silvercel and Aquacel Ag treatments induced better cosmetic outcomes regarding wound closure and scarring.

Challenges and innovations in treating chronic and acute wound infections: from basic science to clinical practice

Acute and chronic wound infection has become a major worldwide healthcare burden leading to significantly high morbidity and mortality. The underlying mechanism of infections has been widely investigated by scientist, while standard wound management is routinely been used in general practice. However, strategies for the diagnosis and treatment of wound infections remain a great challenge due to the occurrence of biofilm colonization, delayed healing and drug resistance. In the present review, we summarize the common microorganisms found in acute and chronic wound infections and discuss the challenges from the aspects of clinical diagnosis, non-surgical methods and surgical methods. Moreover, we highlight emerging innovations in the development of antimicrobial peptides, phages, controlled drug delivery, wound dressing materials and herbal medicine, and find that sensitive diagnostics, combined treatment and skin microbiome regulation could be future directions in the treatment of wound infection.

Evaluation of a Multifunctional Polyvinylpyrrolidone/Hyaluronic Acid-Based Bilayer Film Patch with Anti-Inflammatory Properties as an Enhancer of the Wound Healing Process

The management of acute and chronic wounds is still a socioeconomic burden for society due to the lack of suitable tools capable of supporting all the healing phases. The exponential spread of diabetes worldwide and the consequent increase of complicated diabetic ulcers require further efforts to develop scalable, low-cost, and easy-to-use treatments for tackling this emergency. Recently, we explored the fabrication of a polyvinylpyrrolidone/hyaluronic acid-based bilayer wound dressing, characterizing its physicochemical features and detailing its excellent antimicrobial activity. Here, we further demonstrate its biocompatibility on fibroblasts, keratinocytes, and red blood cells. The bilayer shows anti-inflammatory properties, statistically reducing the level of IL-6, IL-1β, and TNF-α, and a capacity to accelerate wound healing in vitro and in healthy and diabetic mice models compared to untreated mice. The outcomes suggest that this bilayer material can be an effective tool for managing different skin injuries.

Controlled-release iodine foam dressings demonstrate broad-spectrum biofilm management in several in vitro models

Multiple in vitro models were utilised to evaluate the biofilm management capabilities of seven commercially-available wound dressings, varying in composition and antibacterial ingredients, to reduce common aerobic, anaerobic, and multispecies biofilms. The Center for Disease Control bioreactor was used to evaluate single species Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) 24 and 48 hours biofilms, as well as a multispecies biofilm consisting of these two organisms in addition to Enterococcus faecalis (E. faecalis). As wound biofilms often exist in hypoxic wound environments, a direct contact anaerobic model system was used to evaluate efficacy on Bacteroides fragilis (B. fragilis). Biofilm control was evaluated against P. aeruginosa in the drip flow bioreactor model, where a constant flow of proteinaceous media is used to create a more challenging and wound-like model. The results demonstrated that biofilm management capabilities varied amongst wound dressings. Two dressings, a controlled-release iodine foam dressing and a silver nanocrystalline dressing, showed potent >4 log reductions in recovered organisms compared with untreated controls in all biofilm models evaluated. The effectiveness of other dressings to manage bioburden varied between dressing, test organism, and model system. A silver foam dressing showed moderate biofilm control in some models. However, biofilm exposure to methylene blue and gentian violet-containing foam dressings showed negligible log reductions in all in vitro biofilm methods examined. The data outlined in this in vitro study support the use of the iodine foam dressing for wounds with infection and biofilm.

The Efficacy of Silver-Based Electrospun Antimicrobial Dressing in Accelerating the Regeneration of Partial Thickness Burn Wounds Using a Porcine Model

(1) Background: Wounds with damages to the subcutaneous are difficult to regenerate because of the tissue damages and complications such as bacterial infection. (2) Methods: In this study, we created burn wounds on pigs and investigated the efficacy of three biomaterials: polycaprolactone-gelatin-silver membrane (PCLGelAg) and two commercial burn dressings, Aquacel^® Ag and UrgoTul^TM silver sulfadiazine. In vitro long-term antibacterial property and in vivo wound healing performance were investigated. Agar diffusion assays were employed to evaluate bacterial inhibition at different time intervals. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and time-kill assays were used to compare antibacterial strength among samples. Second-degree burn wounds in the pig model were designed to evaluate the efficiency of all dressings in supporting the wound healing process. (3) Results: The results showed that PCLGelAg membrane was the most effective in killing both Gram-positive and Gram-negative bacteria bacteria with the lowest MBC value. All three dressings (PCLGelAg, Aquacel, and UrgoTul) exhibited bactericidal effect during the first 24 h, supported wound healing as well as prevented infection and inflammation. (4) Conclusions: The results suggest that the PCLGelAg membrane is a practical solution for the treatment of severe burn injury and other infection-related skin complications.

Antimicrobial stewardship of antiseptics that are pertinent to wounds: the need for a united approach

Long before the nature of infection was recognized, or the significance of biofilms in delayed healing was understood, antimicrobial agents were being used in wound care. In the last 70 years, antibiotics have provided an effective means to control wound infection, but the continued emergence of antibiotic-resistant strains and the documented antibiotic tolerance of biofilms has reduced their effectiveness. A range of wound dressings containing an antimicrobial (antibiotic or non-antibiotic compound) has been developed. Whereas standardized methods for determining the efficacy of non-antibiotic antimicrobials in bacterial suspension tests were developed in the early twentieth century, standardized ways of evaluating the efficacy of antimicrobial dressings against microbial suspensions and biofilms are not available. Resistance to non-antibiotic antimicrobials and cross-resistance with antibiotics has been reported, but consensus on breakpoints is absent and surveillance is impossible. Antimicrobial stewardship is therefore in jeopardy. This review highlights these difficulties and in particular the efficacy of current non-antibiotic antimicrobials used in dressings, their efficacy, and the challenges of translating in vitro efficacy data to the efficacy of dressings in patients. This review calls for a unified approach to developing standardized methods of evaluating antimicrobial dressings that will provide an improved basis for practitioners to make informed choices in wound care.

A Risk-Stratified Peri-Operative Protocol for Reducing Surgical Site Infection after Cesarean Delivery

Background: Surgical site infections (SSI) are multifaceted. Pre-operative, intra-operative, and post-operative factors influence the risk of developing an infection. Our objective was to evaluate the effectiveness of an infection risk-stratification checklist, utilizing known SSI risk factors, and a tailored surgical protocol for SSI prevention in women undergoing cesarean delivery. Patients and Methods: A prospective project to reduce SSI was conducted for women undergoing cesarean delivery on the resident staff service at a midwestern, urban tertiary care hospital. Patients were categorized according to an SSI risk-stratification checklist as high risk or low risk. The low-risk group received the local standard of care (single prophylactic dose of pre-operative intravenous antibiotics and a standard pressure dressing). In the high-risk group, prophylactic antibiotic agents were given pre-operatively and continued for the first 24 hours post-operatively. Additionally, patients at high risk received an absorbent dressing (Mepilex Ag^®; Mölnlycke Health Care AB, Gothenburg, Sweden) that was applied in the operating room and worn for one week. Results: The overall rate of SSIs decreased from 6.1% (pre-study rate) to 1.4% after initiation of the protocol, a 77% reduction (p < 0.001). The low- and high-risk groups did not differ in infection rate (0% and 1.4%, respectively; p < 0.59). Both deep incisional and organ/space SSIs decreased after initiation of the protocol (91% and 62% decrease, respectively). Conclusion: Stratifying patients into high- and low-risk groups with tailored peri-operative management strategies reduced overall SSIs. The protocol incorporates known risk factors for SSI in a surgical procedure with high rates of SSI. This approach offers a structured method that can be adopted by other hospital systems for SSI prevention in patients undergoing cesarean delivery.

In vitro antimicrobial effects of chlorhexidine diacetate versus chlorhexidine free base dressings

OBJECTIVE

The aim of this study was to investigate the in vitro antimicrobial performance of a chlorhexidine diacetate dressing and a chlorhexidine free base dressing to determine if the free base form of chlorhexidine has the potential to be an effective alternative to the chlorhexidine salts used in conventional, chlorhexidine-based antimicrobial dressings.

METHOD

Dressing samples were inoculated with clinically relevant pathogenic microorganisms including Gram-positive and Gram-negative bacteria, yeasts and fungus, and subsequently evaluated for in vitro log₁₀ reduction at 1-, 3-, and 7-day time points. Chlorhexidine mole content was also calculated as a function of dressing surface area for both sample types to allow for formulation-independent comparison between the dressings.

RESULTS

The chlorhexidine free base dressing demonstrated >0.5 log₁₀ superior mean antimicrobial efficacy at 67% of the experimental time points and equivalent mean antimicrobial efficacy (≤0.5 log₁₀ different) at the remaining time points when compared with the chlorhexidine diacetate dressing. The chlorhexidine free base dressing was also found to contain 36% less chlorhexidine mole content than the chlorhexidine diacetate dressing.

CONCLUSION

Our results suggest that a dressing formulated with chlorhexidine free base can deliver in vitro antimicrobial performance at both a magnitude and rate that meets or exceeds that of a chlorhexidine diacetate-based dressing, while also allowing for a reduction in total chlorhexidine content per dressing. These findings could be of particular interest to researchers developing new antimicrobial technologies as well as to infection preventionists when evaluating antimicrobial products for use on clinical patients at elevated risk of infection.

Risk and clinical impact of bacterial resistance/susceptibility to silver-based wound dressings: a systematic review

Objective:

To perform a systematic review of the literature on bacterial resistance, tolerance and susceptibility of silver within the context of wound therapy using silver-based dressings.

Methods:

A literature search was carried out using PubMed, Embase and Cochrane Library databases, the focus was whether results from microbiological experimental in vitro tests with reference strains and clinical wound isolates are reflected in clinical practice with regards to their ‘resistance’ profiles, comparable with those observed for antibiotics. The search results were allocated to six categories: resistance and resistance mechanism, in vitro tests with standard strains and wound isolates, prevalence and incidence, impact on clinical practice and impact on antibiotic therapy as well as reviews, expert opinions and consensus.

Results:

Based on all findings of the literature, it cannot be confirmed that a related clinical resistance to silver-ions in silver-based dressings has clinical impact, although endogenous and exogenous genetic resistance patterns have been described and intensively investigated. A translation of these genetic resistance-expression structures to phenotypic appearances, similar to those known for antibiotics, has not been demonstrated for silver in the literature.

Conclusion:

It can be concluded that there is no definitive evidence available and further studies should be conducted.

Manuka honey chelates iron and impacts iron regulation in key bacterial pathogens

AIM

The aim of this study was to test the hypothesis that Manuka honey (MH) chelates iron and promotes an iron-limiting environment, which contributes to its antimicrobial activity.

METHODS AND RESULTS

Employing a ferrozine-based assay, we observed that MH is an iron chelator that depletes iron from solution. Siderophores are small molecules that bind ferric iron (III) with high affinity and their levels are upregulated by bacteria under iron-limiting conditions. We demonstrated by quantitating siderophore production that Escherichia coli and Pseudomonas aeruginosa treated with MH sub-minimum inhibitory concentrations (sub-MIC) experience an iron-limiting environment and increase siderophore production. In addition, supplementation with ferrous iron (II) significantly increased growth of E. coli, Staphylococcus aureus and P. aeruginosa cultured at their MH MIC above that observed in nonsupplemented controls. By contrast, supplementation with ferric iron (III) significantly increased growth for only E. coli and P. aeruginosa, above their nonsupplemented controls.

CONCLUSIONS

Manuka honey chelates iron, thereby generating an iron-limiting environment for E. coli and P. aeruginosa, and to a lesser extent S. aureus, which contributes to its antimicrobial properties.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our work demonstrates that MH-induced iron chelation is an antimicrobial mechanism that differentially impacts the bacterial species tested here. Iron chelation affects multiple diverse physiological processes in bacteria and would contribute to the lack of bacterial resistance to MH. Iron metabolism is tightly regulated; bacteria require this essential nutrient for survival, but in excess it is toxic. Additional exploration of MH's iron chelation mechanism will facilitate its future use in mainstream medicine.

Superiority of silver-foam over porcine xenograft dressings for treatment of scalds in children: A prospective randomised controlled trial

AIM

Our aim was to compare two different regimens for the treatment of children with partial-thickness scalds. These were treated with either a porcine xenograft (EZderm^®, Mölnlycke Health Care, Gothenburg, Sweden) or a silver-foam dressing (Mepilex^® Ag, Mölnlycke Health Care, Gothenburg, Sweden).

METHODS

We organised a prospective randomised clinical trial that included 58 children admitted between May 2015 and May 2018 with partial-thickness scalds to The Burn Centre in Linkoping, Sweden. The primary outcome was time to healing. Secondary outcomes were pain, need for operation, wound infection, duration of hospital stay, changes of dressings, and time taken.

RESULTS

The patients treated with silver-foam dressing had a significantly shorter healing time. The median time to 97% healing for this group was 9 (7-23) days compared to 15 (9-29) days in the porcine xenograft group (p = 0.004). The median time to complete healing for the silver-foam group was 15 (9-29) days and for the porcine xenograft group 20.5 (11-42) days (p = 0.010). Pain, wound infection, duration of hospital stay, and the proportion of operations were similar between the groups. Number of dressing changes and time for dressing changes were lower in the silver-foam dressing group (p = 0.03 for both variables).

CONCLUSIONS

We compared two different treatments for children with partial-thickness scalds, and the data indicate that wound healing was faster, fewer dressing changes were needed, and dressing times were shorter in the silver-foam group.