Introduction: Antimicrobial resistance is a significant public health challenge worldwide, especially in Gram-negative bacteria such as Pseudomonas aeruginosa. In recent years, P. aeruginosa has shown increasing multi- and pan-drug resistance, even to colistin, which is considered to be the last line of defence against resistant bacteria. Black cumin or Nigella sativa L., globally used as a spice, contains the bioactive compound thymoquinone, which is promising as a natural antibacterial agent due to its chemical properties. The high cost and complexity of developing new antibiotics is a significant obstacle and often leads to high attrition rates. However, computational chemistry is a promising approach that optimises the selection of candidates and supports the development of targeted antibacterial agents. This can speed up the discovery process and reduce costs in the ongoing fight against antimicrobial resistance.

Methods: The pharmacokinetic properties of thymoquinone and its pharmacological potential and bioavailability were computationally evaluated using the SwissADME tool. The topologies of the receptor proteins were analysed using the CASTp web server, and triple molecular docking simulations were performed using AutoDock Vina 1.1.2. Molecular visualisation and analysis were performed with PyMol and DS Visualizer.

Results: Thymoquinone fulfils all of Lipinski's rules of five criteria, which indicates favourable pharmacokinetic properties for potential therapeutic use. Molecular docking simulations show a strong binding affinity to the MvfR protein in P. aeruginosa, which is an important regulator of virulence and quorum sensing. Seven (out of nine) models showed consistent interactions with a root mean square deviation (RMSD) of less than 5 Å, often involving the amino acid Ile236.

Conclusions: Computational chemistry can enhance the development of new antibiotics. Thymoquinone shows favourable pharmacokinetics and a strong binding affinity to the MvfR protein in P. aeruginosa. Thymoquinone shows potential as an antimicrobial agent against P. aeruginosa, but further in vitro and in vivo tests, including toxicological studies, are needed to evaluate its cytotoxicity.

Listeria monocytogenes remains a critical foodborne pathogen responsible for listeriosis, a severe illness with high mortality rates, particularly among immunocompromised individuals, pregnant women, and the elderly. The persistence of this pathogen in food production environments presents a serious challenge to public health and food safety. While traditional chemical preservatives have been widely used to control microbial contamination, growing concerns regarding their potential health risks and environmental impact have intensified the search for natural alternatives.

Among these alternatives, essential oils (EOs) have emerged as promising antimicrobial agents due to their potent bioactive properties. Derived from aromatic plants such as Zingiber officinale (ginger), Origanum vulgare (oregano), and Thymus vulgaris (thyme), EOs contain key antimicrobial compounds—thymol, carvacrol, and eugenol—that exert bactericidal effects by disrupting bacterial cell membranes and interfering with essential metabolic functions. This mode of action has been extensively studied, with numerous reports confirming their inhibitory effects against L. monocytogenes in diverse food matrices, including dairy products, meat, and fresh produce.

Despite their potential, challenges remain regarding the stability, volatility, and sensory impact of EOs in food applications. Recent advances in encapsulation technologies, such as nanoemulsions and liposomal delivery systems, have been explored to enhance their controlled release and improve efficacy in food systems. This systematic review consolidates current research on the antimicrobial properties of EOs, their mechanisms of action, and their practical applications in food preservation. Additionally, it outlines technological innovations that aim to optimize EO-based preservation strategies, emphasizing the need for further studies to ensure their commercial viability and regulatory compliance.

Food safety and food security cannot be considered without considering the One Health concept (1). This approach underscores the interdependence of health challenges compromising people, animals, plants, and the environment in which they coexist. Antimicrobial resistance is one of these threats, and the food chain is considered an important reservoir of antibiotic resistance genes (2). The food industry produces wastes and by-products from a variety of sources which have the potential to mitigate environmental impacts and be effective against pathogenic foodborne bacteria (3,4). In addition to by-products, natural sources have demonstrated significant antimicrobial and antioxidant properties, emphasizing the potential of natural extracts derived from the food chain to enhance food safety (5). This study aimed to assess the antimicrobial activity of natural products from northern Portugal, including Hibiscus sabdariffa L., Punica granatum L., and Castanea sativa hedgehog, to understand their potential as bioactive compounds. To prepare the crude extract, we employed a solid–liquid extraction process followed by freeze-drying to obtain the dried extracts. Initially, a screening of the extracts was conducted using the MIC method to evaluate their antimicrobial activity against key pathogens, including Listeria monocytogenes, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, and more. Subsequently, the best-performing extract was analyzed for its physicochemical properties, including antioxidant capacity and phenolic compound content. Hibiscus sabdariffa L. exhibited MIC values of 7.81 mg/mL against both Gram-positive and Gram-negative bacteria, demonstrating bactericidal activity. Punica granatum L. showed MIC values ranging from 1.95 mg/mL to 3.91 mg/mL, while the hedgehog extract of Castanea sativa, displayed the most effective activity, with MIC values between 0.250 mg/mL and 1.00mg/mL. Castanea sativa hedgehog extract was further analyzed for its antioxidant activity and phenolic compound contents. Overall, this study highlights the promising role of these natural extracts as antimicrobial agents against pathogenic bacteria and the necessity for further investigations.

The emergence of new pathogens and the increased rise in antimicrobial resistance warrants the search for novel sources of therapeutic agents. Even though secondary metabolites with notable biological activities have been isolated from medicinal plants, it has been shown that some of these metabolites originate from the endophytic fungi associated with the plants. The capabilities of endophytic fungi are not limited to the production of secondary metabolites; these microorganisms are able to produce industry-significant enzymes with broad applications. In this study, four (4) endophytic fungi isolated from Asparagus densiflorus leaves were screened for their antimicrobial, antioxidant, and extracellular enzymatic activities. The sequencing of the ITS region revealed that all four isolates belong to the phylum Ascomycota. The antimicrobial activity of the fungal endophytes' crude extracts was tested against Psuedomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae, where MIC values ranged from 0.63 to 1.25 mg/ml. The ferric reducing antioxidant power assay revealed that the crude extracts demonstrated minimal antioxidant activity. All the isolates except AspL-3 were observed to possess laccase activity,;however, only AspL-3 possesses the protease activity. All the isolates were observed to possess peroxidase activity. The results obtained in this study further highlight that medicinal plants are an excellent source of fungal endophytes' significant biological and biotechnological potential.

Biofilm formation by Coagulase Negative Staphylococci (CoNS) represents a critical challenge in device-associated infections, often leading to treatment failures. While Staphylococcus epidermidis has been extensively studied, the biofilm-forming potential of other CoNS species remains underexplored. This study analysed 152 isolates belonging to 11 CoNS species obtained from individuals with infections, with the aim of assessing interspecies variability in biofilm formation and its potential clinical implications.

The 152 isolates were evaluated for their capacity to form biofilms using the microtiter biofilm assay. Statistical analyses were conducted to ascertain associations between biofilm formation in the various CoNS species.

The majority of CoNS isolates (64,47%) demonstrated a high capacity for biofilm production, while only 7,24% were classified as non-producers. Despite the variability observed between the isolates, no statistically significant differences were identified in the ability to form biofilms between the different species.

The results obtained in this study offer significant insights into the biofilm forming capacity of CoNS, which may have substantial ramifications for the formulation of novel therapeutic strategies aimed at mitigating biofilm formation and, by extension, the reduction in the prevalence of infections within hospital environments.

Acknowledgements: This work was supported by project UIDB/00772/2020 funded by the Portuguese Foundation for Science and Technology (FCT). This work was also supported by LAQV-REQUIMTE, which is financed by national funds from FCT/MCTES (UIDB/50006/2020 and UIDP/50006/2020).

The human body hosts a diverse community of microorganisms, with the gastrointestinal tract being the most densely colonized, hosting a thousand microbial species collectively referred to as the gut microbiota. Recent studies have demonstrated that the gut microbiota maintains multidirectional and communicational connections with various organs through metabolic, endocrine, neural, humoral, and immunological pathways. Alterations in this gut--organ axis can lead to a wide range of health issues beyond gastrointestinal disorders which affect other organ systems. Emerging evidence highlights the intricate relationship between diet and microbiota in the onset and progression of diseases. Personalized nutrition has gained attention as a strategy to identify specific microbiome traits that predict responses to dietary components. This approach holds promise for designing targeted dietary interventions that promote favorable health outcomes by modulating the gut microbiota. This systematic review explores current insights into the mechanisms underlying gut--organ interactions and examines the potential of personalized nutrition for disease prevention taking advantage of these mechanisms. Furthermore, it addresses existing limitations in understanding the mechanistic pathways and the implementation of personalized nutrition as a preventive strategy. Finally, by summarizing the latest findings, this review aims to provide a clearer understanding of the gut microbiota's role in systemic health and its modulation through dietary strategies, paving the way for innovative approaches in preventive medicine.

Enterococcus spp. are ubiquitous Gram-positive bacteria present in the gastrointestinal tract of humans and animals, as well as in various environmental niches. Over recent decades, Enterococcus spp. have emerged as significant opportunistic pathogens in healthcare-associated infections, with vancomycin-resistant E. faecium identified as a critical health threat. In this context, the One Health concept underscores the interconnection of human, animal, and environmental health, highlighting the importance of intervention fields such as antimicrobial resistance and food safety.

This study aimed to isolate and analyse the genetic diversity of enterococci from a diverse range of samples across One Health domains: sick (n=18) and healthy (n=17) humans, sick (n=13) and healthy (n=14) animals, canteen food (n=11), public transportation surfaces (n=8), and surface water (n=8). Samples were cultured on enterococci-selective media, with and without vancomycin supplementation. Approximately 20% of characteristic colonies were selected and confirmed at the genus level, followed by DNA extraction and RAPD-PCR using primers OPC15 and GTG5 in independent reactions. Amplification analysis and dendrogram construction were performed using the BioNumerics software to obtain relationship patterns within and across One Health sectors.

A total of 148 isolates were obtained from selective media, comprising 81 environmental, 27 animal-, and 35 human-derived isolates, including 24 from vancomycin-supplemented media. Overall, no distinct clustering by sample type or One Health sector was observed, suggesting the widespread dissemination of genetically diverse enterococci across these settings. However, isolates from surface water and clinical samples showed high genetic similarity (≥80–95%), with some clinical clusters also containing isolates from healthy humans.

These findings confirm the widespread dissemination of enterococci across One Health sectors, including presumptive vancomycin-resistant enterococci, and underscore the need for further biosurveillance studies.

Introduction: Dengue is a viral disease transmitted by Aedes mosquitoes, endemic in over 100 countries, including Brazil. It represents a significant public health challenge due to its high incidence and the simultaneous circulation of all four virus serotypes, creating a hyperendemic scenario. This situation complicates efforts for prevention and control, making it a persistent concern for healthcare systems. The state of Rio Grande do Sul has seen a notable rise in dengue cases in 2024, highlighting the need to understand its epidemiological trends, impact on healthcare infrastructure, and contributing factors. Methods: Data were collected from the Department of Informatics of the Unified Health System (DATASUS) on dengue cases in Rio Grande do Sul from January 2021 to December 2024. The data were analyzed based on the following variables: epidemiological profile, hospitalization rates, and clinical outcomes. Results: From 2021 to 2024, 329,185 dengue cases were reported in Rio Grande do Sul, with 212,321 (64%) occurring in 2024, peaking in April (84,513 cases). A 400% increase was observed in 2024 compared to 2023, 200% compared to 2022, and 1800% compared to 2020. The epidemiological profile remained consistent, with 54% of cases in females and 60% in patients aged 20-49. Most patients were of White ethnicity (82%). Regarding outcomes, 73% did not require hospitalization, and 75% recovered, following trends from previous years. Conclusions: The significant rise in dengue cases in Rio Grande do Sul in 2024, particularly with a 400% increase compared to 2023, highlights the influence of favorable climate conditions, including increased rainfall and higher temperatures, which promote mosquito proliferation. Additionally, factors such as urban water accumulation and insufficient mosquito control measures contribute to the surge. Despite this, the epidemiological profile and clinical outcomes remained consistent, with most cases not requiring hospitalization and the majority of patients recovering.

This work studies the antibacterial activity of chitosans prepared with controlled physicochemical characteristics against Gram-positive and Gram-negative reference bacteria. The optimal conditions in acetic acid and chitosan concentration were determined, and the disk diffusion method was used to evaluate the antimicrobial activity. All prepared chitosans, P CHTs, show an inhibition zone that varies between 14mm and 18mm depending on the strain and the physicochemical characteristics of the chitosan (degree of acetylation, DA; molar mass, Mv; and surface structure). These chitosans demonstrate enhanced antibacterial activity compared to the tested commercial chitosans, C CHTs. The effect of DA is particularly interesting. P CHTs exhibit significantly better antibacterial activity than C CHTs, especially against Gram-negative bacteria, where the improvement can reach 100%. Totally deacetylated chitosan (DA=0%) provided the highest inhibition diameter and the lowest MIC/MBC values. Also, PCHTs with Mv>80000 g/mol showed relatively high antimicrobial activity compared to Mv< 20000 g/mol. Interference of the surface structure with the effects of other parameters (Mv, DA, and strain) was observed. The antibacterial activity of the prepared chitosan (DA=0%) against E. faecalis was improved by 21% and 6% compared to Gentamicin and Ciprofloxacin. For the other bacteria, this chitosan provides 68 to 86% of the activity of Gentamicin and 49 to 80% of that of Ciprofloxacin.

Legumes not only establish beneficial symbiosis with rhizobia but are also colonized by other endophytic bacteria, which are believed to play a significant role in plant fitness. However, the molecular mechanisms through which non-rhizobial bacteria respond to host-derived signals remain poorly understood compared to those of the well-studied rhizobia–legume symbiosis. In this study, the responses of two non-rhizobial endophytic bacteria, Pseudomonas sp. Q1 and Kosakonia sp. MH5, to chickpea root exudates were analyzed using high-throughput proteomics. Proteomic analysis revealed the differential expression of proteins involved in metabolism, cell envelope biosynthesis, stress response, oxidative stress defense, chemotaxis, nitrogen metabolism, type IV secretion systems, and transmembrane transport.

A notable finding was the upregulation of the gacS gene (2,754 bp) in the proteome of Pseudomonas sp. Q1 following exposure to chickpea root exudates. This gene encodes GacS, a hybrid histidine kinase and a critical component of the Gac two-component signal transduction system. To explore the functional role of GacS, a gacS knockout mutant of Pseudomonas sp. Q1 was generated. The mutant ∆gacS strain showed no significant differences in swarming or swimming motility, biofilm formation, or phosphate solubilization compared to the wild-type strain. However, siderophore production in the mutant was reduced by approximately 8.8%, while the biosynthesis of antimicrobial metabolites remained unaffected. Additionally, under iron deficient conditions, subclover plants inoculated with the mutant ∆gacS exhibited significantly lower growth compared to those inoculated with the wild-type strain.

These findings indicate that GacS in Pseudomonas sp. Q1 is only partially involved in regulating key plant-beneficial traits, suggesting that other two-component signal transduction systems may compensate for GacS function in this strain. Further studies are needed to fully understand the role of GacS in plant–bacteria interactions. This research enhances our understanding of the molecular dialogue between chickpea and its endophytic bacteria and identifies potential genetic targets to improve plant–microbe interactions.