Search Results (121)

Antimicrobial resistance (AMR) is one of the most serious threats to global public health, driven in part by extensive antibiotic use in food-producing animals. The poultry industry, a major contributor to the global animal protein supply, has depended on antibiotics for growth promotion and disease control, thereby contributing to the emergence and dissemination of AMR zoonotic bacteria. This review synthesizes current evidence on the potential of phytochemicals (PCs), plant-derived bioactive compounds, as sustainable non-antibiotic alternatives for controlling bacterial foodborne pathogens in poultry. Relevant literature including in vitro and in vivo studies assessing PCs against major poultry-associated zoonotic bacteria, including Salmonella enterica, Campylobacter spp., Clostridium perfringens, Listeria monocytogenes, and pathogenic Escherichia coli, is examined. Evidence indicates that PCs exert antimicrobial and anti-virulence effects through mechanisms like bacterial membrane disruption, inhibition of quorum sensing and virulence gene expression, modulation of gut microbiota, and enhancement of host immune responses. In vivo studies demonstrate reductions in pathogen colonization and improvements in gut health and performance metrics in poultry. Despite these promising findings, challenges remain in bioavailability, dose optimization, standardization, and regulatory approval. Overall, PCs represent a promising component of integrated antimicrobial stewardship strategies in poultry production, with significant implications for mitigating zoonotic AMR transmission. Full article

The deployment of insect-resistant rice cultivars is a sustainable strategy for pest control, while the adaptation of pest insects to resistance limits the efficiency of resistant rice varieties. The cytochrome P450 gene CYP4C61 was previously identified as a key locus underlying brown planthopper (BPH, Nilaparvata lugens) adaptation to the resistant rice variety IR36, but its metabolic function remained unknown. Here, we integrated RNAi-mediated gene silencing, untargeted metabolomics, and transcriptomics to elucidate the metabolic role of CYP4C61 in the BPH population virulent to resistant rice IR36. CYP4C61 silencing significantly impaired BPH fitness, including reduced body weight, increased mortality, disrupted feeding behavior, and a progressive body darkening of BPH reared on IR36 rice, reflecting dopamine accumulation entering the melanization branch. Metabolomic analysis identified 240 differentially abundant metabolites in silenced BPH on IR36, revealing a pattern of precursor reduction and product accumulation in the dopamine pathway. Transcriptomic analysis also revealed that CYP4C61 knockdown altered gene expression in the dopamine pathway in a host-dependent manner. Enzyme-linked immunosorbent assay validated dopamine accumulation after CYP4C61 knockdown exclusively in the IR36 background. Our integrated multi-omics evidence indicates that CYP4C61 contributes to dopamine homeostasis in the virulent BPH, providing a mechanistic link between a P450 gene and dopamine-mediated insect adaptation to resistant host plants. Full article

Abortion in cattle entails substantial economic loss, and rapid identification of abortigenic pathogens is critical for timely on-farm response and reduction in human exposure risk. In 2024, two Holstein cows from a small farm in Inner Mongolia aborted in close succession without an obvious cause. Vulvar swabs from both cows, one afterbirth sample, and whole blood from one aborted fetus were collected. Shotgun metagenomic sequencing was performed, followed by host-read removal, taxonomic profiling with Kraken2, de novo assembly of Brucella-aligned reads, and whole-genome comparison. Serological tests, Gram-stained smears, and Brucella genus- and species-specific qPCR assays were used as orthogonal verification. Putative resistance and virulence determinants were screened against CARD and VFDB. Brucella reads were detected in all samples, with the highest relative abundance in the 138-afterbirth (96%). qPCR assays detected Brucella DNA and B. abortus-specific signals in all four samples. A draft Brucella genome was assembled from the 138-afterbirth sample and was phylogenetically placed within B. abortus, showing relatedness to previously circulating Chinese lineages. Cows 138 and 198 were RBT-positive with SAT titres of 1:100 (++). No acquired Brucella resistance genes were identified in CARD. Within 72 h of sample receipt, B. abortus was reported to the farm and local authorities and emergency biosecurity measures were implemented. This field investigation shows that metagenomic sequencing, when combined with conventional serology, microscopy, and targeted qPCR, can support rapid etiological investigation when culture is delayed, hazardous, or biosafety level 3 facilities are unavailable. Full article

Avibacterium paragallinarum (A. paragallinarum) is the primary causative agent of infectious coryza in chickens. Infection often leads to growth retardation in broilers and a 10% reduction in egg production, reaching over 40% in laying hens. The problem is particularly severe under intensive farming conditions, significantly jeopardizing global poultry health and farming profitability. From a ‘One Health’ perspective, this not only disrupts the stability of the food supply chain, but also increases antibiotic usage due to disease prevention and control needs, thereby aggravating antimicrobial resistance (AMR) and posing a global public health challenge. This review systematically summarizes advances in the pathogenesis of A. paragallinarum and the protective immunity induced by subunit vaccines. It focuses on the infection mechanisms of A. paragallinarum, emphasizing its colonization strategies in the infraorbital sinus and nasal epithelium of chickens, and analyzes the roles of key virulence factors such as hemagglutinin and capsule in adhesion, colonization, and immune evasion. We integrate the tissue-specific pathogenesis of A. paragallinarum with the role of respiratory commensal microbiota in facilitating infection, providing an in-depth analysis of the bacterium’s key immune evasion strategies, thus offering novel insights into host–pathogen-microbiome interactions. Concurrently, to the best of our knowledge, this review provides the first comprehensive overview of current developments in subunit vaccines and their immunoprotective properties, with special attention to limitations in eliciting mucosal immune responses. By delving into the pathogen-host interaction mechanisms, this review aims to inform the optimization of subunit vaccine design and immunization strategies. Ultimately, it seeks to establish a theoretical basis and practical framework for precise control of A. paragallinarum. Full article

Recent studies have reported skin microbiome dysbiosis in patients with photodermatoses, featuring enriched Staphylococcus aureus colonization and decreased microbiome diversity. We propose that ultraviolet radiation (UVR), along with atypical antimicrobial peptides, may exert selective pressure on the skin microbiome, while cytokine dysregulation and a reduction in commensal bacteria amplify microbial dysbiosis. Dysbiotic microorganisms further release pathogen-associated patterns and virulence factors, and activate tissue-resident memory T cells, which collectively contribute to local inflammation. These mechanisms establish the skin microbiome as a potential target for early intervention. Potential therapeutic strategies may include antibiotics, phototherapy, bleach baths, phage therapy, and microbiota-based therapies. This review integrates current findings from microbial ecology, molecular biology, and host immunology to outline a conceptual framework linking UVR exposure, microbiome alterations, and cutaneous immune responses, while emphasizing the current limitations and evidence gaps in this field. Full article

Grade C molar-incisor pattern periodontitis (C-MIP) is a rapidly progressive form of periodontal disease affecting young individuals that is often linked to a highly virulent genotype of Aggregatibacter actinomycetemcomitans (Aa). Although Aa is present in the healthy oral microbiome, its transition into subgingival tissue correlates with the conversion from healthy to diseased status within the periodontal pocket. These changes may be due to immune evasion strategies attributed to Aa exotoxins. We previously demonstrated that a host cell protein, cellugyrin, plays a critical role in exotoxin internalization and subsequent cytotoxicity. Herein, we assess the contribution of cellugyrin to Aa phagocytosis and intracellular trafficking in human macrophages. Confocal imaging demonstrated that Aa co-localizes with cellugyrin. Importantly, cellugyrin-deficient macrophages exhibited a significant reduction in phagocytosed Aa. Furthermore, we analyzed the role of retrograde trafficking in Aa survival. Retro-2-mediated inhibition of this trafficking pathway resulted in increased intracellular Aa, likely due to increased survival. Collectively, our findings suggest that cellugyrin is involved in Aa phagocytosis and that retrograde trafficking may play a role in subsequent host cell clearance of Aa. Full article

Background/Objectives: Necrotic enteritis (NE), induced by Clostridium perfringens, is responsible for significant economic losses in the poultry industry worldwide. The growing restrictions on antibiotic use have driven the search for alternative strategies for disease control. The purpose of this study is to isolate and characterize lytic phages targeting multidrug-resistant C. perfringens type G recovered from chickens with NE. Methods: C. perfringens was isolated from chickens with NE using a culture method with selective TSC agar. Bacterial identification was carried out using biochemical tests and PCR. C. perfringens isolates were toxinotyped by PCR. Antibiotic susceptibility test was performed using the agar dilution method. Bacteriophages were isolated from chicken intestine samples collected from wet markets using the double-layer agar technique. Phage isolates were characterized by host range, one-step growth, stability, and whole genome sequencing. The efficacy of phage CPP8 in controlling multidrug-resistant C. perfringens type G was evaluated in GAM broth. Results: In this study, 16 C. perfringens strains were isolated from 100 chickens suspected of NE. Among these isolates, 10 (62.5%) belonged to type G, while the remaining 6 (37.5%) were type A. A total of 11 phages capable of lysing C. perfringens type G were isolated from the chicken intestine. Among them, phage CPP8 has the widest host range, short latent period, large burst size, and high stability. Moreover, the genome of CPP8 lacked genes related to antibiotic resistance, toxins, virulence factors, or lysogeny. Treatment with CPP8 resulted in a significant reduction in viable counts of C. perfringens at 37 °C. Conclusions: Our findings highlight phage CPP8 as a promising candidate for bio-control of multidrug-resistant C. perfringens type G. Full article

Candida albicans (C. albicans) is an opportunistic fungal pathogen capable of causing a wide range of infections, including mucosal and systemic candidiasis. In the oral cavity, fungi represent a minor component of the microbiome but can significantly contribute to morbidity, particularly under conditions of dysbiosis or immunosuppression. Treatment remains challenging due to increasing multidrug resistance. This study investigates the in vitro antifungal potential of Viroelixir, a standardized polyphenol blend derived from green tea and pomegranate and enriched in catechins (including epigallocatechin gallate, EGCG), ellagitannins (notably punicalagin), ellagic acid, and flavonoids, with particular focus on its potential anti-virulence mechanisms. Methods: The effect of Viroelixir on C. albicans growth was assessed using MTT assay, optical density measurements, colony formation, carbohydrate quantification, and pH variation analysis. Biofilm formation, morphological transition, ROS production, necrosis, virulence gene expression, adhesion, and host immune responses were also evaluated. Results: Viroelixir significantly inhibited C. albicans growth and reduced colony formation compared with untreated controls. The formulation also inhibited biofilm formation and markedly reduced pseudohyphal development, reaching up to 94% reduction under specific treatment conditions. Flow cytometry analysis showed an increase in dead fungal cells, reaching approximately 88% following exposure to Viroelixir at the highest tested concentration. In addition, Viroelixir reduced the transcript levels of several virulence-associated genes, including SAP1–SAP9 and EAP1. In epithelial cell co-culture models, pre-treatment of C. albicans with Viroelixir reduced fungal adhesion and attenuated epithelial inflammatory responses, including IL-6, IL-8, and hBD-2 production, and was associated with reduced activation of the TLR4-NF-κB signaling pathway. Conclusions: These findings suggest that the antifungal and anti-virulence effects observed may be associated with the polyphenolic compounds present in the Viroelixir formulation, highlighting its potential as a promising in vitro antifungal candidate against C. albicans. Full article

Multidrug-resistant Acinetobacter baumannii is a major nosocomial pathogen for which bacteriophages are being explored as alternative antibacterial agents. In this study, we isolated and characterized AUBFM01, a lytic phage active against MDR A. baumannii, and performed an initial assessment of its interaction with PMA-differentiated THP-1 macrophages. AUBFM01 was evaluated by host range testing, adsorption and one-step growth assays, lytic activity, stability testing, biofilm disruption, whole-genome sequencing, and flow cytometry-based macrophage profiling. The phage showed rapid adsorption, a short latent period of approximately 30 min, and a burst size of about 165 phage particles per infected cell. It remained stable under moderate temperature and near-neutral pH conditions and significantly reduced preformed A. baumannii biofilm biomass in vitro. Genomic analysis identified a 41,354-bp double-stranded DNA genome lacking detectable lysogeny-associated genes, antibiotic resistance determinants, and known bacterial virulence factors. In THP-1 macrophages, AUBFM01 exposure was associated with reduced cell viability and with enrichment of a resting/intermediate-like CD86-defined phenotype among the remaining cells, including after endotoxin reduction. These findings identify AUBFM01 as a lytic anti-Acinetobacter phage with antibiofilm activity and notable macrophage-associated effects that warrant further mechanistic and safety investigation. Full article

Helicobacter pylori (H. pylori) is the primary etiological agent for chronic gastritis, peptic ulcers, and gastric adenocarcinoma. The alarming rise in multidrug-resistant (MDR) strains, particularly against clarithromycin (CLR), metronidazole (MNZ), and levofloxacin (LVX), has severely compromised standard therapies. Thus, there is an urgent clinical need for novel antimicrobial agents that operate through distinct mechanisms to bypass resistance pathways and mitigate gastric cancer risk. We designed and synthesized a series of antimicrobial peptides, focusing on the proteolytically stable all-D-amino acid enantiomer, DT7-3, derived from a probiotic-sourced template. Minimum inhibitory concentrations (MICs) were determined against standard strains and 11 clinical MDR isolates via the broth microdilution method. Antimicrobial mechanisms were elucidated using scanning electron microscopy (SEM) for morphology, fluorescence-based assays for anti-adhesion activity, and real-time qPCR to quantify virulence gene expression (babA, ureA, and vacA). Biocompatibility was assessed using defibrinated sheep erythrocytes, gastric epithelial cells (GES-1), and representative beneficial gut microbiota. Analysis of the clinical isolates revealed resistance rates of 63.6% for CLR/LVX and 81.8% for MNZ, with 54.5% identified as MDR. DT7-3 exhibited superior potency (MIC 1–32 µg/mL) against all strains, significantly outperforming its L-enantiomer counterparts. Mechanistic studies unveiled a “triple-hit” mechanism: (1) rapid membrane disruption; (2) potent inhibition of bacterial adhesion to host cells (~60% reduction at 0.5 × MIC); (3) significant downregulation of critical virulence factors (babA, ureA, and vacA). Furthermore, DT7-3 showed an excellent safety profile, with negligible hemolysis (<5% at 32 µg/mL) and minimal cytotoxicity toward GES-1 cells, yielding a high selectivity index (SI, MHC/MIC) > 32 relative to mammalian cells. Crucially, DT7-3 showed high selectivity for the pathogen over beneficial gut microbiota (MIC > 128 µg/mL, SI > 16). Crucially, DT7-3 maintained potent bactericidal activity (MIC ≤ 16 µg/mL) even under cholesterol-enriched conditions. The engineered D-peptide DT7-3 is a potent candidate for combating MDR H. pylori. Its multifaceted mechanism, targeting bacterial viability while suppressing core virulence factors, positions it as a robust lead compound for next-generation eradication therapies aimed at reducing the burden of H. pylori-associated diseases. Full article

Lactic acid bacteria (LAB) are pivotal microorganisms in the food industry. Current approaches for functional gene validation and trait improvement in LAB primarily rely on traditional gene editing and homologous recombination techniques. These methods are often cumbersome, inefficient, and time-consuming, hindering the rapid and precise customization of strains. This limitation has, to some extent, constrained the rapid selection and industrial application of functional LAB strains. The engineering of LAB through gene editing technologies has significantly advanced both fundamental and applied research. Among these, CRISPR/Cas gene editing has successfully achieved precise modification of multiple genes in various LAB species. Compared to conventional methods, it offers superior editing efficiency and lower operational costs, opening new avenues for functional gene identification and genetic improvement in LAB. However, the application of exogenous CRISPR/Cas systems in LAB faces technical challenges such as high off-target rates, chromosomal abnormalities, and cytotoxicity. The development of endogenous CRISPR/Cas-based editing tools for LAB provides novel pathways for precise regulation, rational design, and flexible application. This paper first outlines the structural components and mechanistic principles of CRISPR/Cas gene editing tools. It then explores the research progress and applications of both endogenous and exogenous CRISPR/Cas systems in LAB. Finally, it provides an outlook on the future application of CRISPR/Cas gene editing technology in LAB, offering a reference for its implementation in this field. The advent of gene editing technologies has significantly propelled functional gene validation and trait improvement in lactic acid bacteria (LAB), thereby advancing both fundamental research and industrial applications. Notably, the CRISPR/Cas system has emerged as a transformative tool enabling precise genetic modification in diverse LAB species, offering marked improvements in editing efficiency and cost reduction relative to conventional approaches. CRISPR/Cas-based editing strategies in LAB are broadly classified into exogenous and endogenous systems. Exogenous systems operate independently of the host’s native immune repertoire, conferring the advantages of broad strain applicability and high editing efficiency. These systems have been successfully deployed for functional gene characterization, metabolic pathway engineering, such as augmenting antimicrobial production, and probiotic safety enhancement via virulence gene deletion. Conversely, endogenous systems leverage the intrinsic CRISPR/Cas machinery of LAB, offering superior biocompatibility and minimized off-target risks. Notable applications include precise gene knockout and integration using the native Type I-E system in Lacticaseibacillus paracasei. This review provides a concise overview of CRISPR/Cas system architecture and mechanisms, followed by a systematic synthesis of research progress and applications for both exogenous and endogenous systems in LAB. Finally, future directions are outlined to guide the continued development and application of CRISPR/Cas technologies in this field. Full article

Bacillus cereus is a major foodborne pathogen responsible for food spoilage and foodborne illness, including strains producing emetic toxins. In this study, two bacteriophages, PBC_MG88 and PBC_MG99, were isolated from wastewater using emetic B. cereus strains as hosts and were comprehensively characterized. Both phages formed clear plaques with halos and exhibited siphovirus morphology. Host range analysis against 172 B. cereus strains showed that PBC_MG88 and PBC_MG99 infected 50 and 60 strains, respectively. One-step growth experiments revealed efficient lytic activity, with latent periods of 20–25 min and burst sizes of 59–63 PFU per infected cell. More than 90% of phage particles adsorbed to host cells within 15 min. Both phages were stable across a wide temperature range (4–55 °C) and pH values (4–11). Genome sequencing revealed ~37 kb double-stranded DNA genomes lacking antibiotic resistance or virulence genes; however, the presence of lysogeny-related genes suggests a temperate lifestyle. Comparative genomic analyses indicated that both phages represent novel species within the genus Lwoffvirus. Biofilm assays demonstrated significant inhibition of B. cereus biofilm formation and reduction of pre-established biofilms. Overall, this study expands knowledge of B. cereus phage diversity and highlights the importance of genomic characterization in phage-based biocontrol research. Full article

Pseudomonas aeruginosa biofilm-associated infections present higher recalcitrance to antimicrobial treatments, contributing to persistent and difficult-to-treat infections. Quorum sensing (QS) regulates various cellular processes that are important for the establishment and survival of microbial communities on the host. However, QS inhibitors for the treatment of P. aeruginosa biofilms remain under-researched, partly due to the complexity of QS signalling pathways and the challenge of developing non-toxic inhibitors. Herein, the bioactivity of 2-{(2E)-2-[1-(pyridin-2-yl)ethylidene]hydrazinyl}-1,3-thiazole-4-carboxylic acid (TTNF37), a novel pyridine-based thiazolyl-hydrazone (PTH), was investigated. The compound antimicrobial activity was evaluated against a broad spectrum of microorganisms, its antioxidant potential was assessed using different assays, and its QS-inhibitory effect on P. aeruginosa was studied using bioreporter strains. The effect on P. aeruginosa biofilm formation was analysed in terms of biomass, culturability, and metabolic activity, structure, and cell membrane integrity, while virulence factors were evaluated through absorbance measurements. In addition, molecular docking studies were performed to predict the drug’s interactions with essential QS proteins and biological targets. TTNF37 exhibited potent antimicrobial activity with low to moderate minimum inhibitory concentrations against clinically relevant Gram-negative and Gram-positive bacteria, as well as fungi and yeasts. It also showed antioxidant activity, with variable effectiveness across different radicals and systems. TTNF37 inhibited the 3-oxo-C12-HSL-dependent QS system of P. aeruginosa in a dose-dependent manner, with reductions ranging from 26% to 98%. It also impaired the production and detection of 3-oxo-C12-HSL, resulting in a 56% and 65% decrease in bioluminescence, respectively. Molecular docking studies revealed strong binding interactions with LasI and LasR proteins, with affinity values exceeding those of furvina, a known potent QS inhibitor. Molecular dynamics simulations validated stable TTNF37 binding to LasR and LasI. Both experimental and docking data indicate a significant interaction with human serum albumin (HSA). TTNF37 also significantly reduced pyocyanin production and prevented biofilm set-up with a reduction of 50% in biomass with pronounced alterations in biofilm structure. These results indicate the potential of TTNF37 and related PTHs for treating biofilm-associated infections. Full article

Verticillium wilt (VW) of cotton caused by the soilborne pathogen Verticillium dahliae is a major disease across cotton production worldwide. The disease can result in yield reductions up to 80% on some occasions. V. dahliae is an asexual fungus and belongs to a relatively small Verticillium genus in the Ascomycota, though both of the mating type idiomorphs are present within some populations. The diversity of V. dahliae is widely associated with vegetative compatibility groups (VCGs), of which six different VCGs are recognised. Of these, isolates belonging to VCGs 1, 2, and 4 are globally distributed and associated with a broad host range, including cotton. Approximately 400 plant species have been recorded as hosts of V. dahliae. The pathogenicity and virulence of V. dahliae in many cases are correlated with VCG designations and hosts of origin. Disease management of VW of cotton still relies on accurate, rapid detection and quantification of V. dahliae using both conventional and molecular approaches. The use of resistant cultivars is the most effective and economical control strategy; however, no cultivars confer complete resistance to the disease. Control strategies including cultural, biological, chemical, and induced-resistance approaches have indicated certain degrees of success in minimising disease damage and diminishing the build-up of pathogen inoculum. In this review, we discuss insights into the VW disease of cotton, and the associated pathogen and current control approaches, as well as future research perspectives. Full article

Phage therapy is the use of bacterial viruses, or bacteriophages, as antibacterial agents. It has been in use for over 100 years and is becoming increasingly common clinically. The first steps of phage therapy include identification of bacteria to be targeted and then obtaining phages with appropriate host ranges. This is followed by various approaches to in vitro phage characterization. Increasingly common for phage phenotypic characterization is the use of kinetic microtiter plate readers. They can both decrease workloads and increase throughput, especially relative to analyses that require plating on agar-based media. These colorimetric/turbidimetric/optical density approaches primarily assess phage-induced culture-wide bacterial lysis, in the shorter term, or instead the phage potential to suppress phage-resistance evolution over longer time frames. Considered here are methods relevant to phage characterization especially for phage-therapy purposes. Discussed are turbidity-reduction assays, determinations of phage antibacterial virulence, and related time-kill curve analysis. All are or can be optical density-based approaches to assessing phage-based bacterial reduction. Emphasis is placed on consideration of the utilities, limitations, and intersections of these similar methods. Emphasized is that the start of “Deviation”—where phage-treated culture turbidity diverges from phage-free controls—may represent a superior endpoint for such optical density-based bacterial-reduction protocols. Full article