Tackling strong biofilm and multi-virulent vancomycin-resistant Staphylococcus aureus via natural alkaloid-based porous nanoparticles: perspective towards near future eradication

Mycosynthesis of zinc oxide nanoparticles using Mucor racemosus with their antimicrobial, antibiofilm, anticancer and antioxidant activities

The unregulated administration of currently available antimicrobial agents resulted in overspreading of resistant microbial phenotypes. In this study, Mucor racemosus was used for biosynthesis of zinc oxide nanoparticles (ZnO NPs) through fungi-based ecofriendly approach. The biosynthesized of ZnO NPs was initially considered based on analytical practices including UV-vis spectroscopy and transmission electron microscopy (TEM). Additionally, their cytotoxicity and anticancer activity were analyzed using suitable cell lines and their antioxidant effect was also assessed. Microbiologically, their inhibitory activity was comparatively evaluated against various methicillinresistant Staphylococcus aureus (MRSA) and methicillinsensitive Staphylococcus aureus (MSSA). Characterization of ZnO NPs displayed a distinct maximum absorption peak at 320 nm appeared in the UV-vis. Also, TEM revealed predominantly spherical ZnO NPs with particle size distribution ranging from 15 to 55 nm (mean size ≃ 40 nm). The normal cell line (Wi-38) illustrated the biosafety of ZnO NPs, where results showed IC50 of 197.2 µg/mL. Furthermore, ZnO NPs exhibited promising suppressive activity on Hep-G2 cancerous cell with IC50 of 51.4 µg/mL. Besides, ZnO NPs displayed antioxidant activity where IC50 was 69.2 µg/mL. As well, the minimum inhibitory concentrations of ecofriendly ZnO NPs against the tested MRSA and MSSA isolates were ranged from 32 to 512 µg/mL. Also, their minimum bactericidal concentrations against the tested MSSA was in lower range, 32-1024 µg/mL, than the recorded range, 128-1024 µg/mL, against the MSSA. Also, the crystal violet (CV) assay showed an eradication potential of the biosynthesized ZnO NPs on MRSA and MSSA biofilm in a range of 23.24-73.96% and 6.63-74.1%, respectively. In conclusion, the ecofriendly synthesized ZnO NPs with antioxidant and anticancer activities demonstrated promising inhibitory effect on planktonic growth form of MRSA and MSSA clinical isolates with capability to eradicate their preformed biofilm. To achieve their full potential, future research needs to enhance the synthesis process to make ZnO NPs more uniform and scalable, as well as investigate their action mechanisms at the molecular level.

Staphylococcus aureus in Inflammation and Pain: Update on Pathologic Mechanisms

Staphylococcus aureus (S. aureus) is a Gram-positive bacterium of significant clinical importance, known for its versatility and ability to cause a wide array of infections, such as osteoarticular, pulmonary, cardiovascular, device-related, and hospital-acquired infections. This review describes the most recent evidence of the pathogenic potential of S. aureus, which is commonly part of the human microbiota but can lead to severe infections. The prevalence of pathogenic S. aureus in hospital and community settings contributes to substantial morbidity and mortality, particularly in individuals with compromised immune systems. The immunopathogenesis of S. aureus infections involves intricate interactions with the host immune and non-immune cells, characterized by various virulence factors that facilitate adherence, invasion, and evasion of the host's defenses. This review highlights the complexity of S. aureus infections, ranging from mild to life-threatening conditions, and underscores the growing public health concern posed by multidrug-resistant strains, including methicillin-resistant S. aureus (MRSA). This article aims to provide an updated perspective on S. aureus-related infections, highlighting the main diseases linked to this pathogen, how the different cell types, virulence factors, and signaling molecules are involved in the immunopathogenesis, and the future perspectives to overcome the current challenges to treat the affected individuals.

Nanotechnology Meets Phytotherapy: A Cutting-Edge Approach to Treat Bacterial Infections

The increasing prevalence of bacterial infections and the rise in antibiotic resistance have prompted the search for alternative therapeutic strategies. One promising approach involves combining plant-based bioactive substances with nanoparticles, which have demonstrated improved antimicrobial activity compared to their free forms, both in vitro, in vivo, and in clinical studies. This approach not only improves their stability but also enables targeted delivery to bacterial cells, reducing side effects and minimising the risk of resistance development, leading to more effective treatments. This narrative review explores the benefits of combining bioactive plant compounds (berberine, catechin, chelerythrine, cinnamaldehyde, ellagic acid, proanthocyanidin, and sanguinarine) with nanoparticles for the treatment of bacterial infections (caused by Staphylococcus aureus, Enterococcus spp., Klebsiella pneumoniae, Acinetobacter baumannii, Escherichia coli, Serratia marcescens, and Pseudomonas aeruginosa), highlighting the potential of this approach to overcome the limitations of traditional antimicrobial therapies. Ultimately, this strategy offers a promising alternative in the fight against resistant bacterial strains, paving the way for the development of more effective and sustainable treatments.

Surface-functionalized UIO-66-NH2 for dual-drug delivery of vancomycin and amikacin against vancomycin-resistant Staphylococcus aureus

BACKGROUND

Conventional antibacterial compounds can inhibit the growth of microorganisms, but their adverse effects and the development of drug limit their widespread use. The current study aimed to synthesize PEG-coated UIO-66-NH2 nanoparticles loaded with vancomycin and amikacin (VAN/AMK-UIO-66-NH2@PEG) and evaluate their antibacterial and anti-biofilm activities against vancomycin-resistant Staphylococcus aureus (VRSA) clinical isolates.

METHODS

The VAN/AMK-UIO-66-NH2@PEG were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS) to determine their size, polydispersity index (PDI), encapsulation efficiency (EE%), zeta-potential, drug release profile, and physical stability. Antibacterial activity was evaluated using minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-kill assays. Biofilm formation by VRSA was assessed using the crystal violet (CV) and minimum biofilm eradication concentration (MBEC) assays. The effect of sub-MIC concentrations of the formulations on the expression of biofilm-related genes (icaA, icaD) and resistance-related genes (mecA, vanA) was investigated using quantitative real-time polymerase chain reaction (RT-qPCR).

RESULTS

As demonstrated by MIC, MBC and time-kill assay, the VAN/AMK-UIO-66-NH2@PEG nanoparticles exhibited enhanced antibacterial activity against VRSA isolates compared to free drugs and prepared formulations. Furthermore, CV and MBEC tests indicated that the VAN/AMK-UIO-66@NH2/PEG can reduce biofilm formation dramatically compared to VAN/AMK and VAN/AMK-UIO-66@NH2, due to its great drug release properties. This study also found that the expression level of the mecA, vanA, icaA, and icaD genes in VAN/AMK-UIO-66@NH2/PEG treated VRSA isolates was substantially decreased compared to other groups.

CONCLUSIONS

These findings highlighted the efficiency of VAN/AMK-UIO-66@NH2/PEG in combating antimicrobial resistance and biofilm formation in VRSA isolates. Future studies, particularly in vivo models, are necessary to evaluate the safety, efficacy, and clinical applicability of these nanoparticles for the treatment of bacterial infections.

Innovative unified impact of magnetite iron nanoparticles and quercetin on broiler chickens: performance, antioxidant and immune defense and controlling of Clostridium perfringens infection

Necrotic enteritis caused by Clostridium perfringens (C. perfringens) is characterized by poor performance and higher mortality rates in poultry farms. Novel dietary intervention involving bioactive molecules loaded into smart magnetized nano-system with a potent antioxidant function (quercetin-loaded Fe3O4-NPs), was evaluated for their impact on growth performance, intestinal immune and antioxidant defenses, and resistance against Clostridium perfringens in a necrotic enteritis challenge model. Four experimental groups comprising a total of 200 one-day-old Ross 308 broiler chickens were fed different diets: a control basal diet, a diet supplemented with quercetin (300 mg/kg), a diet with Fe3O4-NPs (60 mg/kg), and a diet with quercetin-loaded Fe3O4-NPs (300 mg/kg). These groups were then challenged with C. perfringens during the grower period. Dietary inclusion of quercetin-loaded Fe3O4-NPs prominently reduced C. perfringens colonization and its associated virulence genes expression, which subsequently restored the impaired growth performance and intestinal histopathological changes in challenged broilers. Quercetin-loaded Fe3O4-NPs supplemented group displayed higher Lactobacillus and Bifidobacterium counts, upregulation of intestinal host defense antimicrobial peptides related genes (avian β-defensin 6 and 12) and downregulation of intestinal inflammatory regulated genes (Interleukin-1 beta, C-X-C motif chemokine ligand 8, tumor necrosis factor-α, chemokine C-C motif ligand 20, inducible nitric oxide synthase and cycloox-ygenase-2). Intestinal redox balance was boosted via upregulation of catalase, superoxide dismutase, glutathione peroxidase and heme Oxygenase 1 genes along with simultaneous decrease in hydrogen peroxide, reactive oxygen species and malondialdehyde contents in groups fed quercetin-loaded Fe3O4-NPs. Overall, new nutritional intervention with quercetin-loaded Fe3O4-NPs impacted better immune and antioxidant defenses, attenuated C. perfringens induced necrotic enteritis and contributed to better performance in the challenged birds.

Targeting bacterial biofilm-related genes with nanoparticle-based strategies

Persistent infection caused by biofilm is an urgent in medicine that should be tackled by new alternative strategies. Low efficiency of classical treatments and antibiotic resistance are the main concerns of the persistent infection due to biofilm formation which increases the risk of morbidity and mortality. The gene expression patterns in biofilm cells differed from those in planktonic cells. One of the promising approaches against biofilms is nanoparticle (NP)-based therapy in which NPs with multiple mechanisms hinder the resistance of bacterial cells in planktonic or biofilm forms. For instance, NPs such as silver (Ag), zinc oxide (ZnO), titanium dioxide (TiO2), copper oxide (Cu), and iron oxide (Fe3O4) through the different strategies interfere with gene expression of bacteria associated with biofilm. The NPs can penetrate into the biofilm structure and affect the expression of efflux pump, quorum-sensing, and adhesion-related genes, which lead to inhibit the biofilm formation or development. Therefore, understanding and targeting of the genes and molecular basis of bacterial biofilm by NPs point to therapeutic targets that make possible control of biofilm infections. In parallel, the possible impact of NPs on the environment and their cytotoxicity should be avoided through controlled exposure and safety assessments. This study focuses on the biofilm-related genes that are potential targets for the inhibition of bacterial biofilms with highly effective NPs, especially metal or metal oxide NPs.