Search Results (121)

Background/Objectives: Postbiotics derived from lactic acid bacteria are emerging as promising antimicrobial agents due to their antibacterial, antibiofilm, and immunomodulatory properties. Among their metabolites, lactic acid (LA) is thought to play a major role in antimicrobial activity. This study investigated the proteomic response of Pseudomonas aeruginosa and Staphylococcus aureus to Lacticaseibacillus rhamnosus cell-free supernatant (CFS) and compared it with that elicited by LA alone. Methods: Overnight bacterial cultures were exposed to sub-MIC LA or CFS (1:10 for P. aeruginosa and 1:8 for S. aureus; ~12.5–15.6 mM LA) for 6 h at 37 °C. Intracellular proteins were harvested and subsequently quantified and purified to be analysed by HPLC–MS/MS, for quantitative label-free proteomics. Results: Proteomic analysis revealed clear separation of treated samples from controls, with largely overlapping responses to CFS and LA. Hallmark acid-stress adaptations were observed, including urease-mediated pH buffering, confirming that part of the response was driven by mild organic acid. In P. aeruginosa, treatments suppressed virulence pathways (phenazines, T3SS), while shifting metabolism toward lactate utilisation and reinforcing the outer membrane (lipid A, polyamine). In S. aureus, decreased abundance of the SaeRS-regulated immune-evasion factor Sbi, together with changes in envelope, ROS and translation-related proteins, suggested a bacteriostatic-like state. S. aureus differences between CFS and LA were more pronounced; CFS uniquely increased cell-wall defences, oxidative stress (SodA, SodM) and chaperone expression (GroS, GrpE), suggesting stress beyond acidification alone. Conclusions: These findings shed light on the molecular mechanisms underlying bacterial adaptation to CFS and highlight their potential as a novel antimicrobial approach. Full article

Streptococcus pneumoniae contributes significantly to morbidity, mortality, and healthcare costs worldwide due to severe Invasive Pneumococcal Disease (IPD), particularly among young children and vulnerable populations. This review critically examines the current state of pneumococcal disease epidemiology, the evolution of vaccine strategies, and persistent challenges to achieve global control of the disease. The implementation of Pneumococcal Conjugate Vaccines (PCVs) has yielded substantial public health gains, establishing herd protection and sharply reducing vaccine-type IPD incidence. However, this success has been fundamentally challenged by serotype replacement, where non-vaccine serotypes have subsequently emerged to cause a significant proportion of the residual disease burden. This epidemiological shift has necessitated the development and deployment of higher-valency PCVs (PCV15, PCV20, and PCV21) to expand serotype coverage. Furthermore, optimal protection requires personalized strategies for high-risk cohorts where vaccine effectiveness can be compromised. In this context, the review details how pneumococcal vaccination—and particularly PPSV23—serves as an indispensable diagnostic tool to evaluate a broad spectrum of Inborn Errors of Immunity (IEI) and in particular humoral defects. Diagnostic challenges are strained by non-standardized assays and the limited panel of unique serotypes available for testing in the PCV era. The scientific priority is now the development of universal protein-based vaccines, to provide protection against all serotypes and non-encapsulated strains by targeting conserved virulence factors. This integrated approach, combining expanded PCV coverage with novel vaccine technology, is essential to mitigate the ongoing public health burden of pneumococcal disease. Full article

Background: Monkeypox (MPX), caused by the Monkeypox virus (MPOX) of the Orthopoxvirus genus, has re-emerged as a significant global health threat. Once confined to Central and West Africa, the 2022–2025 multi-country outbreaks, predominantly caused by Clade IIb, demonstrated sustained human-to-human transmission and global spread. Objective: This review summarizes current knowledge on MPX virology, epidemiology, clinical presentation, and diagnostic technologies, with a focus on innovations supporting rapid and field-deployable detection in resource-limited settings. Methods: The recent literature (2019–2025), including peer-reviewed studies, WHO and Africa CDC reports, and clinical guidelines, was critically reviewed. Data were synthesized to outline key developments in diagnostic methodologies and surveillance approaches. Results: MPX comprises two genetic clades: Clade I (Congo Basin) and Clade II (West African), which differ in virulence and transmission. Clade IIb is associated with sexual and close-contact transmission during recent outbreaks. Clinical manifestations have shifted from classic disseminated rash to localized anogenital lesions and atypical or subclinical infections. RT-PCR remains the diagnostic gold standard, while emerging assays such as loop-mediated isothermal amplification (LAMP), recombinase polymerase amplification (RPA), and CRISPR/Cas-based platforms show promise for rapid point-of-care (POC) testing. Complementary serological tools, including ELISA and lateral flow assays, enhance surveillance and immune profiling. Conclusions: The resurgence of MPX highlights the urgent need for accessible, sensitive, and specific diagnostic platforms to strengthen surveillance and outbreak control, especially in endemic and resource-constrained regions. Full article

Straw returning is a critical practice with profound strategic importance for sustainable agricultural development. However, within a comprehensive soil health evaluation framework, research analyzing the impact of tobacco straw returning on soil ecosystem health from the perspectives of microbial taxa and functional genes remains insufficient. To investigate the effects of tobacco straw returning on virulence factor genes (VFGs), methane-cycling genes (MCGs), nitrogen-cycling genes (NCGs), carbohydrate-active enzyme genes (CAZyGs), antibiotic resistance genes (ARGs), and their host microorganisms in soil, this study collected soil samples from a long-term tobacco-rice rotation field with continuous tobacco straw incorporation in Shaowu City, Fujian Province. Metagenomic high-throughput sequencing was performed on the samples. The results demonstrated that long-term tobacco straw returning influenced the diversity of soil VFGs, MCGs, NCGs, CAZyGs, ARGs, and their host microorganisms, with richness significantly increasing compared to the CK treatment (p < 0.05). In the microbially mediated methane cycle, long-term tobacco straw returning resulted in a significant decrease in the abundance of the key methanogenesis gene mttB and the methanogenic archaeon Methanosarcina, along with a reduced mtaB/pmoA functional gene abundance ratio compared to CK. This suggests enhanced CH₄ oxidation in the tobacco-rice rotation field under straw returning. Notably, the abundance of plant pathogens increased significantly under tobacco straw returning. Furthermore, a significantly higher norB/nosZ functional gene abundance ratio was observed, indicating a reduced capacity of soil microorganisms to convert N₂O in the tobacco-rice rotation field under straw amendment. Based on the observation that the full-rate tobacco straw returning treatment (JT2) resulted in the lowest abundances of functional genes prkC, stkP, mttB, and the highest abundances of nirK, norB, malZ, and bglX, it can be concluded that shifts in soil physicochemical properties and energy substrates drove a transition in microbial metabolic strategies. This transition is characterized by a decreased pathogenic potential of soil bacteria, alongside an enhanced potential for microbial denitrification and cellulose degradation. Non-parametric analysis of matrix correlations revealed that soil organic carbon, dissolved organic carbon, alkaline-hydrolyzable nitrogen, available phosphorus, and available potassium were significantly correlated with the composition of soil functional groups (p < 0.05). In conclusion, long-term tobacco straw returning may increase the risk of soil-borne diseases in tobacco-rice rotation systems while potentially elevating N₂O and reducing CH₄ greenhouse gas emission rates. Analysis of functional gene abundance changes identified the full-rate tobacco straw returning treatment as the most effective among all treatments. Full article

The nucleoid-associated protein Fis functions as a global regulator that influences various cellular processes in Gram-negative bacteria. In this study, we examined the role of Fis in the transcriptional regulation of type 3 fimbriae in Klebsiella pneumoniae, a notable opportunistic pathogen associated with hospital-acquired infections. Our transcriptional analyses revealed that deleting the fis gene caused a significant upregulation of mrkA and mrkH, the genes responsible for the structure and regulation of type 3 fimbriae, respectively. Additionally, phenotypic assays demonstrated that the Δfis mutant exhibited enhanced biofilm formation and greater adherence to A549 lung epithelial cells compared to the wild-type strain. These effects were restored to wild-type levels in the cis-complemented strain. Electrophoretic mobility shift assays confirmed that Fis directly binds to the regulatory regions upstream of both mrkA and mrkH, indicating that repression occurs through direct interaction with the promoter. In summary, our findings show that Fis acts as a transcriptional repressor of mrkA and mrkH, thereby negatively regulating the expression of type 3 fimbriae, biofilm formation, and adherence. This study highlights Fis as a direct regulator of fimbrial expression and biofilm development in K. pneumoniae, deepening our understanding of its virulence regulatory network. Full article

Background: Genome sequencing is transforming infectious-disease diagnostics, surveillance, and precision therapy by enabling rapid, high-resolution pathogen identification, transmission tracking, and genomic-informed antimicrobial stewardship. Methods: We review contemporary sequencing platforms (short- and long-read), targeted and metagenomic approaches, and operational workflows that connect laboratory outputs to clinical and public health decision-making. We highlight strengths and limitations of genomic AMR prediction, the role of plasmids and mobile elements in resistance and virulence, and practical steps for clinical translation, including validation, reporting standards, and integration with electronic health records. Results: Comparative and population genomics reveal virulence determinants and host–pathogen interactions that correlate with clinical outcomes, improving risk stratification for high-risk infections. Integrating sequencing with epidemiological and clinical metadata enhances surveillance, uncovers cryptic transmission pathways, and supports infection control policies. Despite these advances, clinical implementation faces technical and interpretative barriers, as well as challenges related to turnaround time, data quality, bioinformatic complexity, cost, and ethical considerations. These issues must be addressed to realize routine, point-of-care sequencing. Conclusions: Emerging solutions, including portable sequencing devices, standardized pipelines, and machine-learning models, promise faster, more actionable results and tighter integration with electronic health records. The widespread adoption of sequencing in clinical workflows has the potential to shift infectious disease management toward precision medicine, thereby improving diagnostics, treatment selection, and public health responses. Full article

The growing prevalence of antimicrobial resistance has significantly compromised the efficacy of conventional antibiotic-based interventions in controlling Salmonella infections across human and veterinary settings. This growing challenge necessitates a strategic rethinking of pathogen control, prompting the integration of next-generation therapeutics capable of disrupting Salmonella pathogenesis through novel, antibiotic-sparing mechanisms. In this context, a diverse array of emerging alternatives, including bacteriophages, antimicrobial peptides, probiotics, prebiotics, short-chain fatty acids, nanoparticles, and host-directed immunomodulators, have gained prominence as a promising frontier in non-antibiotic therapeutics. These modalities offer targeted approaches to inhibit Salmonella colonization, virulence expression, and persistence, while minimizing collateral damage to the microbiota and avoiding the propagation of resistance genes. As Salmonella continues to pose a global threat to animal and public health, the development of scalable, resistance-conscious interventions remains a critical priority. Ongoing research efforts are increasingly focused on optimizing delivery systems, dosage strategies, and synergistic combinations to enhance the clinical and field applicability of these alternatives. By harnessing these innovative modalities, the future of Salmonella control may shift toward precision therapeutics that align with One Health principles and sustainable food safety goals. Full article

Deployment of resistant barley cultivars is the most cost-effective and environmentally responsible strategy to manage barley leaf rust caused by Puccinia hordei. Gene predictions based on screening of germplasm with an array of well-characterised pathotypes and application of molecular markers serve as a pivotal step for identification, characterisation, and deploying resistance in breeding programmes. We evaluated 77 barley genotypes from 17 countries using an array of diverse P. hordei pathotypes and molecular markers to predict resistance gene identities. Evaluation and resistance analysis of the panel determined four known all-stage resistance (ASR) genes—Rph2, Rph3, Rph9.am, and Rph25 present individually or in combination, with Rph3 being the most common (33% of entries) and Rph2 the second most frequent (9%). Three entries, CG55, CG56, and CG57, exhibited low infection to all tested pathotypes and were negative for markers associated with Rph7, Rph15, and Rph28, potentially carrying novel uncharacterised resistance. In addition to ASR, our studies demonstrated that the core panel had a high prevalence of adult plant resistance (APR) to P. hordei, occurring in ~83% of entries. By employing markers linked to APR, we were able to partition known APR with Rph24 found in the most lines (60%), followed by Rph23 (17%), Rph20 (14%), and uncharacterised (9%) either individually or in combination. The resistance sources identified in this study can be effectively utilised and combined by breeding programmes to diversify their resistance gene pool. Our study also revealed the virulence and avirulence profiles of 12 Australian P. hordei pts to catalogued Rph genes, providing pathologists and breeders with insights into combining genes relevant to their breeding regions and pathogen shifts. Full article

Background: EHEC O157:H7 causes severe gastrointestinal illness by first colonizing the large intestine. It intimately attaches to the epithelial lining, orchestrating distinctive “attaching and effacing” lesions that disrupt the host’s cellular landscape. While much is known about the well-established virulence factors, there are much to learn about the surface proteins’ roles in a living host. Methods: This study presents the first in vivo characterisation of the surface proteome, i.e., proteosurfaceome, of Escherichia coli O157:H7 EDL933 during intestinal infection, revealing spatial and temporal adaptations critical for colonisation and survival. Using a murine ileal loop model, surface proteomic profiles were analysed at early (3 h) and late (10 h) infection stages across the ileum and colon. Results: In total, 272 proteins were identified, with only 13 shared across all conditions, reflecting substantial niche-specific adaptations. Gene ontology enrichment analyses highlighted dominant roles in metabolic, cellular, and binding functions, while subcellular localisation prediction uncovered cytoplasmic moonlighting proteins with surface activity. Comparative analyses revealed dynamic changes in protein abundance. Conclusions: These findings indicate a coordinated shift from stress adaptation and virulence to nutrient acquisition and persistence and provide a comprehensive view of EHEC O157:H7 surface proteome dynamics during infection, highlighting key adaptive proteins that may serve as targets for future therapeutic and vaccine strategies. Full article

Postpartum uterine diseases such as metritis and endometritis impair reproductive performance and cause substantial economic losses in dairy cows worldwide. The multifactorial etiology, involving polymicrobial infections and complex host immune responses, poses diagnostic and therapeutic challenges. Traditional treatments rely on antibiotics, e.g., cephalosporins like ceftiofur and cephapirin, with broad-spectrum efficacy. However, emerging antimicrobial resistance, biofilm formation by pathogens such as Trueperella pyogenes, Fusobacterium necrophorum, and Escherichia coli, and bacterial virulence factors have reduced effectiveness of conventional therapies. Advances in systems biology, particularly proteomics, metabolomics, and microRNA (miRNA) profiling, have provided unprecedented insights into the molecular mechanisms underpinning uterine disease pathophysiology. Proteomic analyses reveal dynamic changes in inflammatory proteins and immune pathways, whereas metabolomics highlight shifts in energy metabolism and bacterial–host interactions. Furthermore, miRNAs have critical roles in post-transcriptional gene regulation affecting immune modulation, inflammation, and tissue repair, and also in modulating neutrophil function and inflammatory signaling. Uterine inflammation not only disrupts local tissue homeostasis but also compromises early embryo development by altering endometrial receptivity, cytokine milieu, and oocyte quality. Integration of multi-omics approaches, combined with improved diagnostics and adjunct therapies—including micronutrient supplementation and immunomodulators—offers promising avenues for enhancing disease management and fertility in dairy herds. This review synthesizes current knowledge on proteomics, metabolomics, and miRNAs in postpartum uterine diseases and highlights future directions for research and clinical applications. Full article

Malaria persists as a paradigmatic model of co-evolutionary complexity, emerging from the dynamic interplay among a human host, Anopheles vectors, and Plasmodium falciparum parasites. In human populations, centuries of selective pressures have sculpted an intricate and heterogeneous immunogenetic landscape. Classical adaptations, such as hemoglobinopathies, are complemented by a diverse array of genetic polymorphisms that modulate innate and adaptive immune responses. These genetic traits, along with the acquisition of functional immunity following repeated exposures, mitigate disease severity but are continually challenged by the parasite’s highly evolved mechanisms of antigenic variation and immunomodulation. Such host adaptations underscore an evolutionary arms race that perpetually shapes the clinical and epidemiological outcomes. Intermediaries in malaria transmission have evolved robust responses to both natural and anthropogenic pressures. Their vector competence is governed by complex polygenic traits that affect physiological barriers and immune responses during parasite development. Recent studies reveal that these mosquitoes exhibit rapid behavioral and biochemical adaptations, including shifts in host-seeking behavior and the evolution of insecticide resistance. Mechanisms such as enhanced metabolic detoxification and target site insensitivity have emerged in response to the widespread use of insecticides, thereby eroding the efficacy of conventional interventions like insecticide-treated bed nets and indoor residual spraying. These adaptations not only sustain transmission dynamics in intervention saturated landscapes but also challenge current vector control paradigms, necessitating the development of innovative, integrated management strategies. At the molecular level, P. falciparum exemplifies evolutionary ingenuity through extensive genomic streamlining and metabolic reconfiguration. Its compact genome, a result of strategic gene loss and pruning, is optimized for an obligate parasitic lifestyle. The repurposing of the apicoplast for critical anabolic functions including fatty acid, isoprenoid, and haem biosynthesis highlights the parasite’s ability to exploit host derived nutrients efficiently. Moreover, the rapid accumulation of mutations, coupled with an elaborate repertoire for antigenic switching and epigenetic regulation, not only facilitates immune escape but also accelerates the emergence of antimalarial drug resistance. Advanced high throughput sequencing and functional genomics have begun to elucidate the metabolic epigenetic nexus that governs virulence gene expression and antigenic diversity in P. falciparum. By integrating insights from molecular biology, genomics, and evolutionary ecology, this study delineates the multifaceted co-adaptive dynamics that render malaria a recalcitrant global health threat. Our findings provide critical insights into the molecular arms race at the heart of host–pathogen vector interactions and underscore promising avenues for the development of next generation therapeutic and vector management strategies aimed at sustainable malaria elimination. Full article

Strains of Aeromonas salmonicida subsp. salmonicida, a major pathogen of salmonids, typically do not grow at temperatures above 30 °C. The effects of thermal stress on this bacterium have been extensively studied. Recently, we demonstrated that repeated exposure to cyclical thermal stress, reaching up to 37 °C, can induce permanent thermoadaptation in certain strains of this bacterium. Many aspects of this adaptation process remain poorly understood. We generated 88 thermoadapted strains of A. salmonicida subsp. salmonicida capable of sustained growth at 33 °C or higher demonstrating that prolonged heat exposure can shift a substantial proportion of psychrophilic strains toward a more mesophilic-like behavior. Although growth at 35 °C was still weaker than in naturally mesophilic A. salmonicida strains, some thermoadapted strains were able to grow up to 37 °C. North American strains harboring the genomic island AsaGEI1a, a known biomarker, exhibited a significantly reduced capacity for thermoadaptation, suggesting a possible genetic constraint, although genomic analyses indicate that AsaGEI1a itself is not directly responsible for this limitation. Genotyping and phenotypic analyses revealed that thermoadaptation is frequently associated with the loss of Type III secretion system and the A-layer, two key virulence factors. Only 7% of the thermoadapted strains retained both features. Overall, our findings suggest that thermoadaptation may represent a potential mechanism influencing the persistence of some psychrophilic A. salmonicida subsp. salmonicida strains in warming aquatic environments under climate change. Full article

The influenza virus is one of the major global health concerns, causing significant morbidity and mortality in both humans and animals, with substantial impacts on public health. Vaccination remains the primary strategy for managing influenza virus infections; however, the virus undergoes frequent genetic changes through antigenic drift and shift. These mutations lead to new seasonal strains that evade pre-existing immunity. These mutations can potentially result in virulent strains that could trigger future pandemics. Therefore, developing a vaccine capable of providing robust protection despite these genetic changes is essential. Vaccine adjuvants are essential for boosting and directing the immune system’s response, broadening the spectrum of protection, and reducing the amount of antigen required to achieve protection, which is particularly valuable in the face of rapidly evolving strains and during pandemics. Recent advances in adjuvant design and formulation strategies have demonstrated promising improvements in both the overall potency and durability of influenza vaccines, importantly, significant reductions in losses due to influenza infection. This review highlights the current status of different types of influenza virus vaccines, their benefits, and challenges. Further, the review focuses on the role of adjuvants, discussing their advantages, limitations, and methodological approaches, while also considering their potential contribution in developing a universal flu vaccine intended to provide extensive and lasting protection. Full article

The rapid evolution of ventilators and their circuits, coupled with varying maximum usage durations set by different hospitals globally, poses a significant risk for the proliferation and transmission of nosocomial infections in intensive care settings. This study investigated temporal changes in bacterial community structure and predicted metabolic functions in ventilator circuits over a three-week period, with a specific focus on ESKAPE pathogens. The results of full-length 16S rRNA sequencing revealed dynamic shifts in bacterial communities, with an increased bacterial diversity and unique species prevalence in week-2 compared to week-1 and week-3. However, a marked emergence of pathogenic bacteria, including Serratia marcescens and Chryseobacterium indologenes, was observed in week-3 compared to week-1 and week-2. Additionally, the abundance of ESKAPE pathogens, including Klebsiella pneumoniae and Acinetobacter baumannii, was higher in week-3 compared to week-1 and week-2. Furthermore, the PCR analysis revealed a higher detection rate of Pseudomonas aeruginosa and K. pneumoniae in week-3 than in the previous weeks. FAPROTAX analysis further revealed a high abundance of specific functions associated with the pathogens of pneumonia, nosocomial, and septicemia in week-3 compared to the other two weeks, suggesting a shift toward more virulent or opportunistic pathogens with increased utilization of ventilator circuits. These findings highlight the microbial risks associated with prolonged use of ventilator circuits, underscoring the need for continuous microbial surveillance throughout their usage, and provide a foundation for optimizing infection control strategies in intensive care settings. Full article

Antibiotic resistance has emerged as a critical global public health challenge. In this study, we employed metagenomic sequencing to analyze fecal samples from giant pandas (Ailuropoda melanoleuca) across three distinct stages—semi-wild, released, and wild populations—to investigate shifts in antibiotic resistance genes (ARGs) and virulence factors (VFs) during the reintroduction process. Our findings revealed significant variations in the composition of ARG and VF across different stages, with released and wild giant pandas exhibiting similar ARG and VF profiles. Further analyses identified that the increased abundance of ARGs and VFs in both released and wild individuals compared to semi-wild individuals was mainly from Pseudomonas. We hypothesized that the same geographic environment in which ARGs and VFs are transmitted between a host and the environment via mobile genetic elements (MGEs) may be responsible for the similar structure of ARGs and VFs in released and wild giant pandas. Additionally, diet may modulate the gut microbial community, thereby influencing the distributions of ARG and VF. This study elucidated the impact of geographic and dietary factors on ARGs and VFs dynamics in giant pandas, offering valuable insights for mitigating antibiotic resistance and virulence gene dissemination. Full article