Search Results (10,386)

Salmonella enterica serovar Typhimurium (ST) is an intracellular pathogen that survives within macrophages and disseminates to systemic organs, thereby evading host immune defenses. Previous studies have shown that the probiotic yeast Saccharomyces boulardii CNCM I-745 improves survival in ST-infected mice, reduces bacterial translocation, and modulates cytokine expression, including the upregulation of interferon-γ and the downregulation of interleukin-10, both of which are involved in the regulation of inducible nitric oxide synthase (iNOS), a key mediator of macrophage antimicrobial activity. The present study was designed to investigate the transcriptional regulation of iNOS and associated antimicrobial responses in ST-infected RAW264.7 murine macrophages pretreated or cotreated with S. boulardii. Gene expression levels of iNOS and selected cytokines were analyzed in RT-qPCR assays. Bacterial adhesion was quantified by colony-forming unit (CFU) counting, and intracellular survival was assessed using a gentamicin protection assay. S. boulardii did not affect bacterial adhesion, but it significantly reduced intracellular ST survival, particularly under pretreatment conditions (p < 0.05). This effect was associated with increased iNOS gene expression. Interferon-γ expression was mainly induced by pretreatment, whereas tumor necrosis factor-α and interleukin-10 were modulated under cotreatment conditions. These findings indicate that S. boulardii modulates macrophage antimicrobial gene expression and suggest that probiotic pretreatment enhances innate immune responses against intracellular bacterial infections. Full article

Antimicrobial resistance represents one of the most formidable global health crises of the 21st century, driven by the diminishing efficacy of conventional antibiotics due to bacterial adaptation and biofilm formation. In response, antimicrobial nanoformulations have emerged as a transformative therapeutic paradigm, offering multifaceted and innovative mechanisms to combat resistant pathogens. This comprehensive review delineates the broad scope and distinct novelty of nano-enabled antimicrobial strategies, moving beyond the single-target limitations of traditional drugs. We systematically explore the diverse architectural classes of nanoformulations—including metallic, polymeric, and self-assembling nanostructures—and elucidate their unique mechanistic actions. These encompass (1) physical disruption of microbial membranes via electrostatic interactions; (2) catalytic generation of reactive oxygen and nitrogen species to induce an ‘oxidative storm’; (3) intracellular sabotage of essential metabolic pathways; (4) the ‘Trojan horse’ strategy for enhanced drug delivery and bioavailability; (5) efflux pump bypass to counteract a major resistance mechanism; (6) penetration and eradication of resilient biofilms; and (7) disarming pathogens through quorum sensing and virulence inhibition. Furthermore, this review highlights the immunomodulatory potential of nanoformulations; their activity beyond bacteria against fungi, viruses, and parasites; and the critical role of the nano-bio interface defined by surface physicochemistry. We also address the translational pathway, considering challenges in nanotoxicology, scalability, and regulatory approval, alongside the ecological impact and economic horizon of these technologies. This sector is projected to reach USD 5.4 to 8.96 billion by 2033 to 2034, with compound annual growth rates of 11 to 21% across antimicrobial nanomaterials, nanocoatings, and nanomedicine applications. By integrating insights from computational modeling and in silico design, this review underscores how nanoformulations leverage synergistic, multi-target approaches to overcome resistance, enhance therapeutic efficacy, and represent a significant leap forward in the future of infectious disease management. The novelty lies in the holistic and mechanistic synthesis of how nanotechnology is redefining antimicrobial warfare, offering a promising arsenal to avert a post-antibiotic era. Full article

Campylobacter spp. constitutes a significant global public health hazard as it is a leading cause of reported foodborne diseases. Human infection is predominantly acquired through the ingestion of contaminated food, unpasteurized milk and untreated water, prompting the widespread implementation of chemical disinfection across several sectors, from healthcare, domestic environments, and food-processing to animal husbandry. While these biocidal agents encompass multiples classes with different modes of action and efficacy, growing evidence suggests that their extensive and repeated use may unintentionally promote bacterial persistence, tolerance and adaptive responses. Although biocide resistance has been documented in several foodborne pathogens, data on biocide tolerance in Campylobacter spp. remain limited. Available studies report variable degrees of reduced susceptibility to commonly used biocides among isolates originating from poultry production, food-processing environments, and water systems. Importantly, while biocide-induced adaptive responses in Campylobacter spp. may potentially overlap with antimicrobial resistance mechanisms, the extent to which these agents drive co-selection, persistence, or dissemination requires further elucidation. Evidence remains limited on the effects of long-term and repeated exposure under realistic processing conditions, the interplay between stress-induced gene regulation and stable genetic changes, and the contribution of mobile genetic elements, biofilm formation, and microbial communities in shaping antimicrobial resistance evolution. In light of the global health burden imposed by campylobacteriosis and the rising challenge of antimicrobial-resistant Campylobacter, this review brings together current evidence on the role of biocides in shaping bacterial survival, adaptation, and resistance mechanisms. Full article

Avibacterium paragallinarum (Av. paragallinarum), the causative agent of infectious coryza, imposes substantial economic burdens on the poultry industry by inducing growth retardation in broilers and reducing egg production in laying hens by up to 40%. Disease control is hindered by the limited efficacy of available vaccines and the increasing prevalence of antibiotic resistance—challenges that are exacerbated by the pathogen’s capacity to form biofilms, which facilitate bacterial persistence and enhance drug tolerance. To systematically elucidate the genetic determinants underlying biofilm formation in Av. Paragallinarum, we constructed a high-density random mutant library using mini-Tn5 transposon mutagenesis, comprising 3106 individual mutants. Phenotypic screening via crystal violet staining identified 188 mutants displaying altered biofilm-forming capacity relative to the wild-type strain, including 172 with enhanced and 16 with reduced biofilm formation. Sequencing of transposon insertion sites in these mutants revealed 105 disrupted genes involved in diverse biological pathways, including amino acid metabolism, quorum sensing, and transmembrane transport. A representative subset of eight mutants was selected for detailed phenotypic characterization. Their biofilm phenotypes were consistent with the initial screening results; certain mutants exhibited markedly enhanced biofilm formation (e.g., Tn-2206), whereas others, including Tn-1504, Tn-2428, and Tn-2859, showed significant reductions in biofilm production. Notably, these three biofilm-deficient mutants—harboring disruptions in a TonB-dependent receptor (Tn-1504), a GntP family permease (Tn-2428), and a hypothetical protein (Tn-2859)—displayed drastically attenuated virulence in vitro. Compared with the wild-type strain, these mutants exhibited reductions in cytotoxicity (up to 66.38%), cell adhesion (up to 50.68%), and invasive capacity, while maintaining normal growth kinetics. These findings indicate that the identified genes may play crucial roles in biofilm-associated virulence and highlight Tn-1504, Tn-2428, and Tn-2859 as promising candidates for the development of live attenuated vaccines. Collectively, this study provides a comprehensive genetic foundation for the rational design of novel anti-biofilm strategies against Av. paragallinarum. Full article

Insects are widely distributed across the globe and exhibit strong adaptability in diverse living environments, a capability closely linked to the diversity of their gut microbiota. The composition of insect gut bacteria varies with species, living environment, diet, and development stage. In recent years, the widespread application of culture-independent strategies based on molecular biology techniques has provided substantial information for studies on the interaction mechanisms between insects and their gut microbiota. However, culture-dependent strategies aimed at isolating pure cultures remain indispensable. Only by integrating multi-techniques such as bacterial isolation and pure culture, axenic insect technology, and molecular biology can in-depth research be conducted on key gut bacteria of insects. This review summarizes culture-dependent and -independent strategies used for the analysis of the diversity and functions of insect gut microbiota, focusing on the traditional methods and new strategies for microbial cultivation, multi-omics techniques, and axenic insect technology. Recent studies showed that the application of integrated techniques is powerful for illustrating the microbial function and evolution of gut microbiota, and the interactions between intestinal bacteria and their hosts. Studies have shown that the insect gut microbiota plays important roles in the promotion of host growth and development by regulating host metabolic pathways, contributing to host nutrition, and supporting the host in defending against pathogens or degrading toxic compounds. Future research directions and strategies are also proposed, providing insights into further exploration of the interaction mechanisms between symbiotic insect gut bacteria and their hosts, as well as future applications in various fields. Full article

Anthrax is a zoonotic infectious disease characterized by high lethality and transmissibility. Its spores are highly stable and can persist in the environment for long periods. Furthermore, the overuse or improper use of antibiotics may contribute to bacterial resistance, complicating anthrax treatment. Phages can efficiently target and lyse Bacillus anthracis (B. anthracis), significantly reducing pathogen contamination and transmission risks in soil, water, and other environmental media. Compared to traditional chemical disinfectants and antibiotics, phages enable precise pathogen elimination while minimizing ecological disruption. In this study, two phages infecting B. anthracis, vB_BanM-JC307 (JC307) and vB_BanS-YL5 (YL5), were isolated and characterized. Both phages belong to the class Caudoviricetes. Genome sequencing revealed that JC307 and YL5 have sequence lengths of 148,323 bp and 74,568 bp, respectively. Phylogenetic analysis indicates that JC307 is located in the same evolutionary branch as the Nachito phage of the Herelleviridae family, while YL5, although grouped with the Basilisk-like phages, forms an independent branch. As these two phages have been observed to exhibit lytic activity against all nine tested strains of B. anthracis, they could serve as auxiliary tools for pathogen diagnosis and assist in ecological management of anthrax-contaminated areas. Full article

Botrytis cinerea, the causative agent of gray mold, is a major fungal pathogen affecting a wide range of economically important crops. To identify sustainable alternatives to chemical fungicides, this study characterized the biocontrol potential of two bacterial strains, Serratia quinivorans NFX21 and Pseudomonas thivervalensis NFX104, through genomic analysis and functional assays targeting key stages of fungal growth and plant infection. The NFX21 and NFX104 strains significantly inhibited B. cinerea mycelial growth (~35%) and strongly suppressed conidial germination with performances comparable to the reference biocontrol strain Bacillus amyloliquefaciens QST 713. In tomato detached-leaf and whole-plant pot assays, application of NFX21 and NFX104 significantly reduced gray mold incidence and lesion severity relative to nontreated infected plants (53–64%, detached leaves; 12–13%, whole-plant assays), achieving disease control levels similar to those obtained with the commercial biofungicide Serenade ASO^®. Whole-genome sequencing allowed the taxonomic assignment of the NFX strains and revealed a rich repertoire of biosynthetic gene clusters and antifungal determinants. The NFX21 genome contained genes associated with N-acyl-homoserine lactone-mediated quorum-sensing and production of lipopeptides, siderophores, and extracellular lytic enzymes. The NFX104 genome harbored clusters involved in the biosynthesis of multiple siderophores, 2,4-diacetylphloroglucinol and hydrogen cyanide. Moreover, both the NFX21 and NFX104 genomes contained additional low-homology clusters that potentially encode for novel unexplored metabolites. Collectively, these results support the translational potential of NFX21 and NFX104 as biocontrol candidates for sustainable, integrated management of gray mold caused by B. cinerea. Full article

Sunflower (Helianthus annuus L.) production is severely hindered by continuous cropping obstacles, leading to soil degradation and significant yield declines. This study compared soybean–sunflower (G-H) and maize–sunflower (Z-H) rotations against sunflower monoculture (H-H) to elucidate the mechanisms of soil health restoration associated with crop rotation. Our results demonstrated that Z-H and G-H rotations led to a profound yield increase of 103.19% and 82.35%, respectively, with Z-H improving the 100-grain weight by 52.63%. Soil biological revitalization was evidenced by a 98.29% increase in sucrase activity and a 28.92% rise in alkaline phosphatase activity. Metagenomic analysis revealed that the rotation sequences increased bacterial Chao1 richness by 35.29% and fungal Shannon diversity by 20.17%. Specifically, the rotation treatments proactively recruited beneficial taxa such as Pontibacter (Log₂FC > 3.0) and Panaeolus (Log₂FC = 6.88), while effectively suppressing pathogens such as Ceratobasidiaceae. Co-occurrence network analysis identified a complex bacterial scaffold (199 nodes, 53 modules) that provided greater structural robustness than the fungal network (27 nodes). It is concluded that diversified rotations effectively mitigate continuous cropping obstacles by reactivating nutrient cycling and restructuring the rhizosphere into a stable, modular microbial interactome. This study provides a quantitative framework for utilizing biological strategies to restore soil health in degraded agroecosystems. Full article

Filamentous fungal infections of breast implants remain underrecognized compared with infections caused by Candida species and bacteria, despite their potential to induce significant inflammatory pathology. This commentary highlights the distinctive ability of filamentous fungal biofilms to penetrate deeply into the implant capsule, a feature that may contribute to distinct pathogenic behaviour compared with bacterial or yeast biofilms. We discuss how this invasive behavior may contribute to the perception that reported cases represent the first documented breast implant-associated fungal infections, when in fact such infections may be under-recognised and under-investigated. By drawing attention to these mechanisms and their clinical implications, this commentary aims to stimulate greater awareness and further investigation within the fields of infectious diseases and pathogen research. Full article

The global rise in antimicrobial resistance has spurred increased interest in alternative antimicrobial agents, particularly essential oils (EOs). These oils are complex mixtures of volatile compounds that exhibit documented biological activity. This study evaluated antimicrobial and antibiofilm effects of selected EOs against clinically relevant bacterial and fungal pathogens. Antimicrobial activity against planktonic cells was assessed using disc diffusion assays with DMSO-diluted EO solutions against Escherichia coli (E.coli), Staphylococcus aureus (S.aureus), Pseudomonas aeruginosa, Klebsiella pneumoniae, and Candida albicans. Antibiofilm activity of E. coli and S. aureus was examined using ethanol-based EO formulations, with biofilm viability quantified by colony forming unit (CFU) enumeration. Cinnamon (Cinnamomum verum) oil showed the strongest and most consistent activity, inhibiting planktonic and biofilm models. Tea tree (Melaleuca alternifolia), lemongrass (Cymbopogon citratus), rosemary (Rosmarinus officinalis), rose (Rosa damascena), and jasmine (Jasminum officinale) oils showed significant planktonic antimicrobial effects, while jasmine oil (Jasminum officinale) demonstrated pronounced antibiofilm activity against S. aureus, including strong biofilm eradication in several replicates. In contrast, chamomile (Matricaria chamomilla) and sandalwood (Santalum austocaledonicum) oils showed limited or no activity. These findings highlight differences between planktonic and biofilm responses, emphasizing the importance of incorporating biofilm models into antimicrobial evaluation. Overall, Cinnamomum verum and Jasminum officinale oils may serve as complementary antimicrobial agents, warranting further investigation. Full article

Background: Aeromonas veronii is an important bacterial pathogen in crucian carp and can cause serious disease outbreaks and substantial economic losses in aquaculture. Objectives: To evaluate how A. veronii infection and its inactivated vaccine modulate immune responses in Carassius auratus. Methods: 270 juveniles were allocated into three groups: a saline-injected control group (Ctrl), a vaccination group receiving an inactivated A. veronii vaccine (Vac), and an artificial infection group (AIG) subjected to stimulation. Liver, spleen, head kidney, gill, and intestine samples were collected from fish after anesthesia. The relative transcript levels of IgM, IgD, BAFF, MHCII, CD4, BCL6, MyD88, and NF-κB were quantified. For liver transcriptome analysis, the effective library concentration was determined. And the 16S rRNA gene resulting reads of fish gill symbiotic microbiota were processed for downstream bioinformatic analysis. Results: The results showed that the Vac achieved an RPS of 73.33%, and vaccination significantly upregulated multiple immune-related genes in different fish organs. With BAFF transcription across organs emerging as a robust sentinel readout. The Pearson correlation coefficient (r) of BAFF between other genes were all ≥0.8. GO and KEGG enrichment analyses indicated that AIG had more DEGs than Vac (5885 vs. 4008) and Ctrl (6910 vs. 6178), respectively. Some genes in AIG revealed significant over-representation of immune pathways, such as BCL6, MyD88, and NF-κB. The fish gill microbiota comprised a diverse set of low-abundance taxa, the phylum level was dominated by Proteobacteria and Fusobacteriota across all groups; whereas, the Vac group remained broadly closer to the Ctrl group in overall composition. Conclusions: These results indicated marked post-challenge immune–metabolic coupling in the liver, and suggested coordinated immunophysiological interplay between the liver and the spleen. Gill microecology of symbiotic bacteria was affected by vaccination or challenge reactions, which in turn affects the health of the gills or the organism itself. Full article

Background: To evaluate the potential of cefiderocol as a topical ophthalmic antibiotic by determining the susceptibility of keratitis isolates from an extensive panel of Gram-negative bacterial species to this siderophore-cephalosporin class antibiotic. Methods: Minimum Inhibitory Concentrations (MICs) of cefiderocol were determined by the broth dilution method using iron-depleted, cation-adjusted Mueller–Hinton broth. The following Gram-negative bacteria were included: Acinetobacter baumannii (n = 13), Achromobacter xylosoxidans (n = 14), Escherichia coli (n = 15), Klebsiella aerogenes (n = 14), Klebsiella pneumoniae (n = 13), Klebsiella oxytoca (n = 14), Moraxella spp. (n = 15), Proteus mirabilis (n = 13), Pseudomonas aeruginosa (n = 17), Serratia marcescens (n = 14) and Stenotrophomonas maltophilia (n = 12). MIC₉₀ values were calculated for each of the species. Results: MIC₉₀ values (µg/mL): A. baumannii (0.5), A. xylosoxidans (0.25), E. coli (0.5), K. aerogenes (1.0), K. oxytoca (0.5), K. pneumoniae (0.5), Moraxella spp. (0.5), P. mirabilis (0.25), P. aeruginosa (0.5), S. marcescens (0.5), and S. maltophilia (0.25). In total, 100% of the isolates were determined to be susceptible to cefiderocol in vitro except for A. xylosoxidans and Moraxella spp., for which there are no established breakpoints for cefiderocol. Conclusions: Cefiderocol demonstrated in vitro activity against the tested panel of Gram-negative keratitis isolates. The results of this study suggest cefiderocol may be useful for the treatment of keratitis caused by numerous Gram-negative pathogens. Further development of cefiderocol for the topical treatment of Gram-negative keratitis is indicated. Full article

The translation of nucleic acid amplification into practical point-of-care and biosensor-integrated diagnostics is still significantly impeded by the necessity for rapid sample preparation. For this reason, a broad comparison of seven commercially available kits for DNA/RNA extraction containing their temperature-related adjustments was performed. Extracts isolated from SARS-CoV-2-positive nasopharyngeal swabs, viral stocks, as well as laboratory-prepared suspensions of clinically relevant Gram-positive and Gram-negative bacteria were evaluated by recombinase polymerase amplification (RPA) and real-time PCR. In addition, the impact of transport media for SARS-CoV-2 samples was investigated. Extraction performance varied markedly according to the kit, pathogen, sample background. For SARS-CoV-2, rapid extraction was more effective for samples collected in viral transport medium than in inactivation buffer. Across bacterial targets, performance was species dependent, highlighting substantial differences in compatibility between simplified extraction workflows and downstream amplification. Among the rapid methods tested, a simplified QuickExtract protocol (95 °C, 5 min) provided the most consistent overall results, although it did not uniformly match the reference silica-based method for all targets. In conclusion, these results demonstrate that rapid nucleic acid extraction must be thoroughly evaluated as an essential element of the entire sample-to-answer workflow, rather than being chosen as a standalone preprocessing step for point-of-care molecular diagnostics. Full article

Pseudomonas aeruginosa is a major opportunistic pathogen whose adaptive capacity limits the long-term efficacy of antibiotic therapy. Beyond classical resistance mechanisms, antibiotics may also act as stress signals that alter bacterial physiology and evolutionary trajectories. A central element of this response is the SOS regulatory network, controlled by the RecA–LexA system. Although well studied in Escherichia coli, SOS signaling in P. aeruginosa shows distinct regulatory features that remain incompletely understood. This review summarizes experimental and clinical evidence on antibiotic-induced SOS responses in P. aeruginosa, focusing on fluoroquinolones and other genotoxic agents. Fluoroquinolone exposure consistently induces SOS activation and RecA-dependent signaling, affecting short-term antibiotic susceptibility. However, the available evidence does not support a universal role for SOS activation as a major driver of long-term resistance evolution under most tested conditions. Its relationship with antibiotic-induced mutagenesis remains variable: some studies implicate low-fidelity DNA polymerases, whereas others report mutagenesis independent of canonical RecA–LexA control. Beyond mutagenesis, SOS activation may affect integron dynamics, virulence, and biofilm-associated phenotypes. Overall, in P. aeruginosa, the SOS response appears to be a context-dependent modulator of stress adaptation rather than a universal determinant of resistance evolution. Full article

Olive mill wastewater (OMW) is an agro-industrial byproduct rich in polyphenols and other bioactive compounds with documented antioxidant and antimicrobial properties. In this study, purified OMW fractions (RO1 and MD2), previously characterized by high polyphenol content and strong antioxidant activity, were incorporated (10% w/w) into cellulose-based hydrogels intended for topical application. Hydrogels were prepared using carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), hydroxypropyl methylcellulose (HPMC), and methylcellulose (MC) at concentrations of 1.5–2.0% (w/w). The formulations were characterized in terms of organoleptic properties, pH, rheological behavior, swelling capacity, weight loss, antioxidant activity (DPPH assay), and microbiological activity against selected skin pathogens, including antibiotic-resistant strains. Rheological analysis confirmed pseudoplastic behavior suitable for topical administration. OMW-loaded hydrogels exhibited significant radical scavenging activity compared to blank formulations and demonstrated antimicrobial efficacy, supporting the preservation of OMW bioactivity within the polymeric network. The results highlight the potential of cellulose-based hydrogels as sustainable and biocompatible carriers for the valorization of OMW in dermatological applications, particularly for the management of oxidative stress and bacterial skin infections. Full article