Topical Antimicrobial Agents for Burn Wound Care: History and Current Status

In vitro analysis of interactions between Pseudomonas aeruginosa and Candida albicans treated with silver sulfadiazine in wound infections

Background

Microorganisms tend to rely on close relationships with other species to survive. Consequently, biofilms formed by interactions of different species have been shown to delay the wound healing process. Studies suggest these mixed-population infections contribute to the development of drug resistance and inhibition of host immune response. Silver sulfadiazine (SSD) has been shown to effectively decrease the risk of infection in an open wound. Typically, these are bacterial wound infections; however, the role of fungal species needs further attention.

Objectives

The purpose of this in vitro study was to determine the effect of SSD on interactions between Pseudomonas aeruginosa 09-009 (PA1) or P. aeruginosa 09-010 (PA2) and Candida albicans ATTC 64550 (CA).

Methods

A mixture of 4 mL of tryptic soy broth (TSB) and 100 µL of CA and/or PA1 or PA2 (∼106 log cfu/mL) inoculums were deposited into either wells or vials. The wells or vials were then sonicated (50 W for 10 s) to separate microorganisms attached to the walls. After incubation, cell counts were performed at 24 and 48 h for each microorganism using specific media.

Results

Our results show that without SSD treatment, P. aeruginosa exhibits an inhibitory effect on C. albicans. Treatment with SSD demonstrated significant reduction of P. aeruginosa; however, C. albicans persisted. This experiment demonstrates that SSD was effective in reducing the bioburden of both P. aeruginosa strains after 24 and 48 h; however, it was not as effective in reducing C. albicans.

Conclusions

The data suggest that for polymicrobial mixed infections containing Pseudomonas spp. and C. albicans, treatment with SSD may be beneficial but does not provide adequate microorganism eradication. As such, added treatments that provide coverage for Candida infection are necessary. Additional in vivo studies are needed to obtain a better understanding of the complex interactions between these organisms.

Evolution of Burn Care: Past, Present, and Future

Burn care evolved slowly from primitive treatments depicted in cave drawings 3500 years ago to a vibrant medical specialty which has made remarkable progress over the past 200 years. This evolution involved all areas of burn care including superficial dressings, wound assessment, fluid resuscitation, infection control, pathophysiology, nutritional support, burn surgery, and inhalation injury. Major advances that contributed to current standards of care and improved outcomes are highlighted in this article. New innovations are making possible a future where severe burn injuries will require less morbid interventions for acute care and outcomes will restore patients more closely to their pre-injury condition.

ARAG, an Antioxidant-Rich Gel, Shows Superiority to Mepilex Ag in the Treatment of Deep Partial Thickness Burns without Sacrificing Antimicrobial Efficiency

Current treatments for deep tissue burns are limited, and most serve only to enhance hydration or prevent bacterial growth. This leaves burn healing dependent on slow natural processes to debride the wound and reestablish the epidermal and dermal layers of the skin. Infections are well known to destabilize this process through a variety of mechanisms, most notably through increased inflammation and the resulting oxidative stress. In this study, we show that ARAG (an antioxidant-rich antimicrobial gel) can suppress the growth of multiple bacteria commonly found to infect burns (Klebsiella pneumoniae, Proteus vulgaris, Pseudomonas aeruginosa, and Staphylococcus aureus). This inhibition is comparable to that conferred by silver ion release from burn dressings such as Mepilex-Ag. We further show, using a porcine model for deep partial-thickness burns, that ARAG allows for enhanced wound healing over Mepilex-Ag, the current standard of care. Histological findings indicate this is likely due to increased wound debridement and dampening of late inflammatory processes, leading to more balanced physiologic healing. Taken together, these findings show promise for ARAG as a superior alternative to the current standard of care.

Infections in Burn Patients

Infections are the leading cause of mortality in burn patients who survive their initial resuscitation. Burn injury leads to immunosuppression and a dysregulated inflammatory response which can have a prolonged impact. Early surgical excision along with support of the multidisciplinary burn team has improved mortality in burn patients. The authors review diagnostic and therapeutic challenges as well as strategies for management of burn related infections.

Improving the antimicrobial activity of old antibacterial drug mafenide: Schiff bases and their bioactivity targeting resistant pathogens

Background: Increasing rates of acquired resistance have justified the critical need for novel antimicrobial drugs. One viable concept is the modification of known drugs. Methods & results: 21 mafenide-based compounds were prepared via condensation reactions and screened for antimicrobial efficacy, which demonstrated promising activity against both Gram-positive and Gram-negative pathogens, pathogenic fungi and mycobacterial strains (minimum inhibitory concentrations from 3.91 μM). Importantly, they retained activity against a panel of superbugs (methicillin- and vancomycin-resistant staphylococci, enterococci, multidrug-resistant Mycobacterium tuberculosis) without any cross-resistance. Unlike mafenide, most of its imines were bactericidal. Toxicity to HepG2 cells was also investigated. Conclusion: Schiff bases were significantly more active than the parent drug, with iodinated salicylidene and 5-nitrofuran/thiophene-methylidene scaffolds being preferred in identifying the most promising drug candidates.

Pediatric First-Degree Burn Management With Honey and 1% Silver Sulfadiazine (Ag-SD): Comparison and Contrast

Background The cardinal area of managing fire wounds is guided by adequately evaluating the burn-induced lesion's profundity and size. Superficial second-degree burns are often treated through daily reinstating with fresh sterile bandaging with appropriate topical antimicrobials to allow rapid spontaneous epithelialization. Around the world, a wide variety of substances are used to treat these wounds, from honey to synthetic biological dressings. Objective This study intended to determine honey's therapeutic potential compared with 1% silver sulfadiazine (Ag-SD) in arsenal-caused contusion medicament fulfillment. Methods A total of 70 cases were evaluated in this research work after fulfilling the required selection criteria during the study period of January 2014 to December 2014 and January 2017 to December 2017. Purposive selection criteria were adopted in the study to select research patients. The patients in Group-1 (n = 35) relied on honey as medication, while patients in Group-2 (n = 35) relied on 1% Ag-SD. Results In Group-1, exudation (68.4%) and sloughing (82.9%) were substantially reduced by Days 3 and 5 of therapeutic intervention, respectively. However, in Group-2, a reduction of exudation (17.1%) and sloughing (22.9%) occurred after Days 3 and 5 of treatment, respectively. Completion of the epithelialization process was observed among Group-1 and Group-2 cases. It was detected after Days 7 and 10 of treatment at 36.3% and 77% (Group-1) and 27% and 67% (Group-2), respectively. Around 3 ml of 1% honey was required per body surface area per dressing in Group-1. On the other hand, in Group-2, 2 gm Ag-SD was needed per body surface area per dressing. Conclusion Patients treated with honey found better clinical outcomes in managing superficial partial-thickness burns.

A Narrative Review of the Potential Roles of Lipid-Based Vesicles (Vesiculosomes) in Burn Management

Burn injuries can have a lasting effect on people’s quality of life, as they negatively impact their physical and mental health. Then, they are likely to suffer psychological problems as a result. A serious problem is that deep burns are more challenging to treat due to their slow healing rate and susceptibility to microbial infection. Conventional topical medications used for burn treatment are sometimes ineffective because they cannot optimize their ability of transcutaneous absorption at the targeted site and accelerate healing. However, nanotechnology offers excellent prospects for developing current medical wound therapies and is capable of addressing issues such as low drug stability, water solubility, permeability, and bioavailability. The current review focuses on lipid-based vesicles (vesiculosomes) as an example of advanced delivery systems, showing their potential clinical applications in burn wound management. Vesiculosomes may help overcome impediments including the low bioavailability of active agents, offering the controlled release of drugs, increased drug stability, fewer side effects, and reduced dosing frequency, which will ultimately improve therapeutic efficacy and patient compliance. We discuss the application of various types of vesiculosomes such as liposomes, niosomes, ethosomes, cubosomes, transfersomes, and phytosomes in burn healing therapy, as these demonstrate superior skin penetration compared to conventional burn topical treatment. We also highlight their noteworthy uses in the formulation of natural products and discuss the current status as well as future perspectives of these carriers in burn management. Furthermore, the burn treatment options currently available in the market are also summarized.

Improving Water-Absorption and Mechanical Strength: Lyotropic Liquid Crystalline-Based Spray Dressings as a Candidate Wound Management System

A spray dressing based on lyotropic liquid crystalline (LLC) with adjustable crystalline lattices was investigated in this study. It possesses water-triggering phase transition property and ease of spraying on wound, as well as stable drug encapsulation and controllable drug release. When it comes to wound with exudate, adequate water absorption and sustainable mechanical strength after water absorption was important for a good dressing, while most of the normal LLC dressings were still unable to meet such standards. Herein, a type of hyaluronic acid (HA)-incorporated LLC-based spray dressing (HLCSD) was developed to overcome the above limitations. After comparing HAs with different molecular weights (MWs) and concentrations, 3% HA with MW of 800~1000 kD was chosen as an ideal amount of excipients to add into the HLCSD. The water absorption of HLCSD precursor increased by 150% with the appearance of enlarged water channels. The complex modulus of HLCSD gel also increased from 1 to 100 kPa, which suggested lasting wound coverage and good patient compliance when used clinically. The spraying and phase transition properties of HLCSD was studied and showed acceptable changes. Moreover, good safety comparable with the commercial product Purilon® was also demonstrated in an in vivo acute skin irritation test. Thus, the improved HLCSD was a promising dressing for exudation wound treatment.

Metallodrug Profiling against SARS-CoV-2 Target Proteins Identifies Highly Potent Inhibitors of the S/ACE2 interaction and the Papain-like Protease PLpro

The global spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has called for an urgent need for dedicated antiviral therapeutics. Metal complexes are commonly underrepresented in compound libraries that are used for screening in drug discovery campaigns, however, there is growing evidence for their role in medicinal chemistry. Based on previous results, we have selected more than 100 structurally diverse metal complexes for profiling as inhibitors of two relevant SARS-CoV-2 replication mechanisms, namely the interaction of the spike (S) protein with the ACE2 receptor and the papain-like protease PLpro . In addition to many well-established types of mononuclear experimental metallodrugs, the pool of compounds tested was extended to approved metal-based therapeutics such as silver sulfadiazine and thiomersal, as well as polyoxometalates (POMs). Among the mononuclear metal complexes, only a small number of active inhibitors of the S/ACE2 interaction was identified, with titanocene dichloride as the only strong inhibitor. However, among the gold and silver containing complexes many turned out to be very potent inhibitors of PLpro activity. Highly promising activity against both targets was noted for many POMs. Selected complexes were evaluated in antiviral SARS-CoV-2 assays confirming activity for gold complexes with N-heterocyclic carbene (NHC) or dithiocarbamato ligands, a silver NHC complex, titanocene dichloride as well as a POM compound. These studies might provide starting points for the design of metal-based SARS-CoV-2 antiviral agents.

Recent advances in nanotherapeutics for the treatment of burn wounds

Moderate or severe burns are potentially devastating injuries that can even cause death, and many of them occur every year. Infection prevention, anti-inflammation, pain management and administration of growth factors play key roles in the treatment of burn wounds. Novel therapeutic strategies under development, such as nanotherapeutics, are promising prospects for burn wound treatment. Nanotherapeutics, including metallic and polymeric nanoformulations, have been extensively developed to manage various types of burns. Both human and animal studies have demonstrated that nanotherapeutics are biocompatible and effective in this application. Herein, we provide comprehensive knowledge of and an update on the progress of various nanoformulations for the treatment of burn wounds.

Efficacy of autologous platelet-rich plasma in treating patients with burn wounds: A protocol for systematic review and meta-analysis

BACKGROUND

Burns are still regarded among severe health problems related to high morbidity and mortality rates globally. In essence, health problems associated with burns can cause significant economic burden to society. Regardless of treatment available options, no best treatment was considered adequate for treating severe burns. In particular, only a few studies have focused on the effect of autologous platelet-rich plasma to treat burn wounds. The present study aim to systematically review existing literature to examine the effectiveness and safety of autologous platelet-rich plasma (PRP) to treat burn wounds.

METHODS

For this study, we will conduct a systematic search using MEDLINE, EMBASE, the Cochrane Library, Web of Science, CINAHL, as well as Scopus to discover randomised controlled trials (RCTs) for the examination of effectiveness and safety of autologous PRP to treat burn wounds from their inception to March 2021 with no language restrictions. Additionally, we will search Google Scholar, ClinicalTrials.gov, as well as the reference lists of studies considered in the research to ascertain possibly eligible studies. We used two independent authors to evaluate studies for inclusion and conduct data extraction. We intend to assess study bias and quality utilizing the Cochrane Collaboration's Risk of Bias Tool 2.0. Also, we will pool study results using the fixed-effects model or random-effects model. Finally, any disagreements emanating from the process will be addressed through discussion or using a third author to mediate situations leading to disagreement.

RESULTS

The study aims at assessing the effectiveness and safety of autologous PRP for treating burn wounds.

CONCLUSION

The study will provide specific substantiation to assess autologous PRP's effectiveness and safety in treating patients with burn wounds.

ETHICS AND DISSEMINATION

The study does not require ethical approval since no published studies are used in it.

OSF REGISTRATION NUMBER

March 29, 2021.osf.io/74z5u. (https://osf.io/74z5u/).