Novel Cyclic Lipopeptides Fusaricidin Analogs for Treating Wound Infections

Nitric Oxide as an Efficient Antimicrobial Treatment for Second-Degree Burn Wounds

INTRODUCTION

Nitric oxide (NO) is a lipophilic gas with potent antimicrobial activity. Several in vitro and in vivo studies have demonstrated the broad-spectrum antimicrobial activity of NO-releasing compounds against bacteria, viruses, and parasites. The objective of this study was to assess the efficacy of topical NO formations with sustained release on microbial reduction in wounds.

MATERIALS AND METHODS

Swine was used as the preclinical animal model because of the similarities of porcine skin to human skin. Second-degree burn wounds were created in 3 pigs and then inoculated with Methicillin-resistant Staphylococcus aureus, Acinetobacter baumannii, or Candida albicans and covered with polyurethane film dressings to create biofilms. After 48 hours, wounds were then treated daily and then recovered for the bacterial burden assessments. Statistical analysis was performed using IBM SPSS statistics 27 using one-way ANOVA.

RESULTS

All treatments significantly reduced (P ≤ .05) the bacterial counts between assessment days 4 and 7. Wounds treated with the NVN4000 (1.8%) exhibited greater than 99.7% bacterial reduction on days 4 and 7. Significant differences (P ≤ .05) were observed in wounds treated with NVN4000 (1.8%) compared to silver sulfadiazine.

CONCLUSIONS

These studies demonstrate that topical NO-releasing formulations effectively reduce the microbial burden of several microorganisms and exhibit superior antimicrobial efficacy compared to silver sulfadiazine in the porcine wound model.

Unveiling a New Antimicrobial Peptide with Efficacy against P. aeruginosa and K. pneumoniae from Mangrove-Derived Paenibacillus thiaminolyticus NNS5-6 and Genomic Analysis

This study focused on the discovery of the antimicrobial peptide (AMP) derived from mangrove bacteria. The most promising isolate, NNS5-6, showed the closest taxonomic relation to Paenibacillus thiaminolyticus, with the highest similarity of 74.9%. The AMP produced by Paenibacillus thiaminolyticus NNS5-6 exhibited antibacterial activity against various Gram-negative pathogens, especially Pseudomonas aeruginosa and Klebsiella pneumoniae. The peptide sequence consisted of 13 amino acids and was elucidated as Val-Lys-Gly-Asp-Gly-Gly-Pro-Gly-Thr-Val-Tyr-Thr-Met. The AMP mainly exhibited random coil and antiparallel beta-sheet structures. The stability study indicated that this AMP was tolerant of various conditions, including proteolytic enzymes, pH (1.2-14), surfactants, and temperatures up to 40 °C for 12 h. The AMP demonstrated 4 µg/mL of MIC and 4-8 µg/mL of MBC against both pathogens. Time-kill kinetics showed that the AMP acted in a time- and concentration-dependent manner. A cell permeability assay and scanning electron microscopy revealed that the AMP exerted the mode of action by disrupting bacterial membranes. Additionally, nineteen biosynthetic gene clusters of secondary metabolites were identified in the genome. NNS5-6 was susceptible to various commonly used antibiotics supporting the primary safety requirement. The findings of this research could pave the way for new therapeutic approaches in combating antibiotic-resistant pathogens.

Staphylococcus aureus and biofilms: transmission, threats, and promising strategies in animal husbandry

Staphylococcus aureus (S. aureus) is a common pathogenic bacterium in animal husbandry that can cause diseases such as mastitis, skin infections, arthritis, and other ailments. The formation of biofilms threatens and exacerbates S. aureus infection by allowing the bacteria to adhere to pathological areas and livestock product surfaces, thus triggering animal health crises and safety issues with livestock products. To solve this problem, in this review, we provide a brief overview of the harm caused by S. aureus and its biofilms on livestock and animal byproducts (meat and dairy products). We also describe the ways in which S. aureus spreads in animals and the threats it poses to the livestock industry. The processes and molecular mechanisms involved in biofilm formation are then explained. Finally, we discuss strategies for the removal and eradication of S. aureus and biofilms in animal husbandry, including the use of antimicrobial peptides, plant extracts, nanoparticles, phages, and antibodies. These strategies to reduce the spread of S. aureus in animal husbandry help maintain livestock health and improve productivity to ensure the ecologically sustainable development of animal husbandry and the safety of livestock products.

Breakthrough treatments for accelerated wound healing

Skin injuries across the body continue to disrupt everyday life for millions of patients and result in prolonged hospital stays, infection, and death. Advances in wound healing devices have improved clinical practice but have mainly focused on treating macroscale healing versus underlying microscale pathophysiology. Consensus is lacking on optimal treatment strategies using a spectrum of wound healing products, which has motivated the design of new therapies. We summarize advances in the development of novel drug, biologic products, and biomaterial therapies for wound healing for marketed therapies and those in clinical trials. We also share perspectives for successful and accelerated translation of novel integrated therapies for wound healing.

Biocontrol potential of lipopeptides produced by Paenibacillus polymyxa AF01 against Neoscytalidium dimidiatum in pitaya

Pitaya canker, caused by Neoscytalidium dimidiatum, is one of the most important fungal diseases that cause significant losses in production. To replace chemical pesticides, the use of biocontrol strains to manage plant diseases has been the focus of research. In this study, the bacterial strain AF01, identified as Paenibacillus polymyxa, exhibited significant antifungal effects against N. dimidiatum and four other pitaya fungal pathogens. The strain P. polymyxa AF01 produces 13 fusaricidins, which directly inhibit mycelial growth, spore germination and germ tube elongation by causing the membrane integrity and cell ultrastructure to incur irreversible damage. Pot experiment and yield test confirmed that AF01 provided preservative effects by reducing the disease index. In comparison to the untreated control groups, RNA-seq data showed that P. polymyxa AF01 selectively blocked some transcription and translation processes and inhibited RNA and DNA structural dynamics, energy production and conversion, and signal transduction, particularly cell wall biosynthesis, changes in membrane permeability, and impairment of protein biosynthesis. Thus, P. polymyxa AF01 could be potentially useful as a suitable biocontrol agent for pitaya canker.

Effect of Moringa oleifera Leaf Extract on Excision Wound Infections in Rats: Antioxidant, Antimicrobial, and Gene Expression Analysis

The present study investigated the wound healing activity of Moringa oleifera leaf extract on an infected excision wound model in rats. Infection was induced using methicillin-resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa. An investigation was also done to study the effect of Moringa extract on the vascular endothelial growth factor (VEGF) and transforming growth factor-beta 1 (TGF-β1) gene expression in vitro using human keratinocytes (HaCaT). The methanol extract of M. oleifera leaves was analyzed for the presence of phytochemicals by LCMS. The antimicrobial activity of the extract was also determined. Wound contraction, days for epithelization, antioxidant enzyme activities, epidermal height, angiogenesis, and collagen deposition were studied. M. oleifera showed an antimicrobial effect and significantly improved wound contraction, reduced epithelization period, increased antioxidant enzymes activity, and reduced capillary density. Effect of the extract was less in wounds infected with P. aeruginosa when compared to MRSA. The VEGF and TGF-β1 gene expression was increased by M. oleifera.