Search Results (505)

This review explores the biofilm architecture and drug resistance of Enterococcus faecalis in clinical and environmental settings. The biofilm in E. faecalis is a heterogeneous, three-dimensional, mushroom-like or multilayered structure, characteristically forming diplococci or short chains interspersed with water channels for nutrient exchange and waste removal. Exopolysaccharides, proteins, lipids, and extracellular DNA create a protective matrix. Persister cells within the biofilm contribute to antibiotic resistance and survival. The heterogeneous architecture of the E. faecalis biofilm contains both dense clusters and loosely packed regions that vary in thickness, ranging from 10 to 100 µm, depending on the environmental conditions. The pathogenicity of the E. faecalis biofilm is mediated through complex interactions between genes and virulence factors such as DNA release, cytolysin, pili, secreted antigen A, and microbial surface components that recognize adhesive matrix molecules, often involving a key protein called enterococcal surface protein (Esp). Clinically, it is implicated in a range of nosocomial infections, including urinary tract infections, endocarditis, and surgical wound infections. The biofilm serves as a nidus for bacterial dissemination and as a reservoir for antimicrobial resistance. The effectiveness of first-line antibiotics (ampicillin, vancomycin, and aminoglycosides) is diminished due to reduced penetration, altered metabolism, increased tolerance, and intrinsic and acquired resistance. Alternative strategies for biofilm disruption, such as combination therapy (ampicillin with aminoglycosides), as well as newer approaches, including antimicrobial peptides, quorum-sensing inhibitors, and biofilm-disrupting agents (DNase or dispersin B), are also being explored to improve treatment outcomes. Environmentally, E. faecalis biofilms contribute to contamination in water systems, food production facilities, and healthcare environments. They persist in harsh conditions, facilitating the spread of multidrug-resistant strains and increasing the risk of transmission to humans and animals. Therefore, understanding the biofilm architecture and drug resistance is essential for developing effective strategies to mitigate their clinical and environmental impact. Full article

Mycoplasma bovis is an important pathogen that is associated with respiratory diseases, mastitis, and arthritis in cattle, leading to significant economic losses in the global cattle industry. Most notably in this study, we pioneer the discovery that its secreted effector ENO1 (α-enolase) directly targets host cytoskeletal proteins for metabolic–immune regulation. Using an innovative GST pull-down/mass spectrometry approach, we made the seminal discovery of β-actin (ACTB) as the primary host target of ENO1—the first reported bacterial effector–cytoskeleton interaction mediating metabolic reprogramming. ENO1–ACTB binding depends on a hydrogen bond network involving ACTB’s 117Glu and 372Arg residues. This interaction triggers (1) glycolytic activation via Glut1 upregulation, establishing Warburg effect characteristics (lactic acid accumulation/ATP inhibition), and (2) ROS-mediated activation of dual inflammatory axes (HIF-1α/IL-1β and IL-6/TNF-α). This work establishes three groundbreaking concepts: (1) the first evidence of a pathogen effector hijacking host ACTB for metabolic manipulation, (2) a novel ‘glycolysis–ACTB–ROS-inflammation’ axis, and (3) the first demonstration of bacterial proteins coordinating a Warburg effect with cytokine storms. These findings provide new targets for anti-infection therapies against Mycoplasma bovis. Full article

Low-level laser therapy (LLLT) is gaining attention as an effective adjunct to non-surgical periodontal treatment. This study evaluates the potential of LLLT to reduce bacterial load in a clinically relevant in vitro subgingival biofilm model and its impact on the inflammatory response. A subgingival biofilm model consisting of seven bacterial species was established. Primary human gingival fibroblasts (GFs) and periodontal ligament cells (PDLs) were cultured. Both biofilms and host cells were treated with the DenLase Diode Laser (980 nm) under various clinically relevant settings. The composition and structure of the seven-species biofilms were evaluated using quantitative PCR and fluorescence microscopy, respectively. The inflammatory response in host cells was analyzed by measuring the gene and protein expression levels of various inflammatory mediators. Laser treatment at power outputs ranging from 0.3 to 2 W had no significant effect on biofilm composition or architecture. LLLT, particularly at higher power settings, reduced the viability in both GFs and PDLs up to 70%. Gene expression levels of inflammatory mediators were only minimally influenced by laser treatment. However, LLLT significantly decreased the secretion of all examined cytokines. These findings suggest that LLLT with a 980 nm diode laser, under clinically relevant conditions, exerts anti-inflammatory rather than antimicrobial effects. Full article

Vibrio alginolyticus, a common Gram-negative opportunistic pathogen of marine animals and humans, is known for its rapid growth in organic-matter-rich environments. However, it remains unclear how it incorporates metabolic pathways in response to diverse carbon and nitrogen sources and rapidly alters gene expression. Increasing evidence suggests that post-transcriptional regulation by RNA-binding proteins and small RNAs (sRNAs) plays a crucial role in bacterial adaptation and metabolism. CsrA (carbon storage regulator A), a conserved post-transcriptional regulator in Gammaproteobacteria, is poorly characterized in Vibrio species. Using integrated transcriptomic and proteomic analyses, we found that CsrA alters the expression of 661 transcripts and 765 protein transcripts in V. alginolyticus, influencing key pathways including central carbon metabolism, amino acid metabolism and transport, quorum sensing, and bacterial secretion systems. Through directed CsrA-RNA EMSAs, we identified several direct mRNA targets of CsrA, including gltB, gcvP, aceE, and tdh, as well as secretion system components (tagH, tssL, yopD, and sctC). Notably, CsrA also directly regulates rraA, a key modulator of ribonuclease activity, suggesting a broader role in RNA metabolism. Our findings establish CsrA as a global regulator in V. alginolyticus, expanding the known targets of CsrA and providing new insights into its regulatory roles. Full article

The spore-forming probiotic Bacillus coagulans JBI-YZ6.3 interacts with the gut epithelium via its secreted metabolites as well as its cell walls, engaging pattern-recognition receptors on the epithelium. We evaluated its effects on human T84 gut epithelial cells using in vitro co-cultures, comparing metabolically active germinated spores to the isolated metabolite fraction and cell wall fraction under unstressed versus inflamed conditions. Germinated spores affected epithelial communication via chemokines interleukin-8, interferon gamma-induced protein-10, and macrophage inflammatory protein-1 alpha and beta after 2 and 24 h of co-culture. Non-linear dose responses confirmed that bacterial density affected the epigenetic state of the epithelial cells. In contrast, the cell wall fraction increased cytokine and chemokine levels under both normal and inflamed conditions, demonstrating that the intact bacterium had anti-inflammatory properties, regulating pro-inflammatory signals from its cell walls. During recovery from mechanical wounding, germinated spores accelerated healing, both in the absence and presence of LPS-induced inflammation; both the metabolite and cell wall fractions contributed to this effect. The release of zonulin, a regulator of tight junction integrity, was reduced by germinated spores after 2 h. These findings suggest that B. coagulans JBI-YZ6.3 modulates epithelial chemokine signaling, supports barrier integrity, and enhances epithelial resilience, highlighting its potential as an efficacious multi-faceted probiotic for gut health. Full article

OPN is a phosphorylated glycoprotein found in all vertebrate organisms and expressed in many tissues and secretions. It is a pleiotropic protein that plays diverse roles in various pathological and physiological processes. OPN is involved in many tissue transformation events such as intestinal and brain development, the regulation of immune system activity, immune cell activation, and inflammatory responses. This protein increases the functionality of the digestive system by regulating the intestinal microbiome and may help strengthen the intestinal barrier. OPN can also influence cognitive development and behavior. In addition, its recent association with cancer has gained critical importance. The increased expression of OPN has been observed in many cancer types, which may promote tumor cell metastasis. OPN is also effective in bacterial interaction and infections; it can prevent bacterial adhesion, supporting the development of new therapeutic approaches for oral care. Furthermore, the supplementation of OPN in infant formula has positively influenced the immune and intestinal health of infants. Many recent studies have focused on these aspects. This article provides a review and comparison of the existing knowledge on the structure and functions of OPN. It emphasizes how milk-derived OPN impacts human and infant health and disease. Full article

Vaccine-induced thrombotic thrombocytopenia (VITT) is a rare thrombotic disorder first identified in 2021 as a catastrophic syndrome associated with anti-SARS-CoV-2 adenoviral vector (AdV)-vaccine administration. It is characterized by the presence of oligo- or monoclonal anti-PF4 antibodies able to induce in vitro platelet activation in the presence of PF4. In addition to this immune-based pathomechanism, random splicing events of the Adv-vector DNA encoding for SARS-CoV-2 spike protein resulting in the secretion of soluble spike variants have been postulated as a possible pathophysiological mechanism. More recently, some novel clinical-pathological anti-PF4-associated entities also characterized by thrombosis, thrombocytopenia, and VITT-like antibodies but independent from heparin or AdV-vaccine administration have been identified. To date, these VITT-like disorders have been reported following the administration of vaccines different from anti-SARS-CoV-2 AdV-vaccines, like human papillomavirus (HPV) and mRNA-based COVID-19 vaccines, following a bacterial or viral respiratory infection, and in patients with a monoclonal gammopathy of undetermined significance. The purpose of this review is to provide an update on the knowledge on VITT pathogenesis, focusing on recent findings on anti-PF4 antibodies, on a possible genetic predisposition to VITT, on VITT-antibody intracellular activated pathways, on lipid metabolism alterations, and on new VITT-like disorders. Full article

Background/Objective: Virus-based vaccine vectors have been widely utilised in commercial vaccines, predominantly for virus infections. They also offer promise for bacterial diseases, for which many vaccines are sub-optimal or ineffective. It is well-established for chlamydial infections, including ovine enzootic abortion, that the major outer membrane protein (MOMP) antigen is protective. Immune responses strongly associated with controlling Chlamydiae include cellular interferon-gamma (IFN-γ) production. Methods: A study was conducted to compare the ability of a modified Orf virus vector directly with a modified sheep maedi visna virus vector to deliver the C. abortus antigen ompA and stimulate vaccine-induced responses in sheep. The Orf virus-based vaccine (mORFV-ompA) was found to be more effective in stimulating MOMP-specific antibodies and cellular antigen-driven IFN-γ in immunised sheep. This mORFV-ompA vaccine was assessed in a follow-up immunogenicity investigation in sheep, where the cellular and humoral immune responses elicited following immunisation with the live or inactivated vaccine were determined. Sheep were immunised intramuscularly with a live mORFV-ompA (n = 10) or an inactivated mORFV-ompA (n = 10). An additional group of 10 sheep served as unvaccinated controls. Results: Serological anti-MOMP antibodies and cellular recall responses of peripheral blood mononuclear cells to the native C. abortus antigen were assessed. Immunisation with either the live or inactivated mORFV-ompA-induced anti-MOMP immunoglobulin-G. Antigen-specific cellular responses, characterised by the secretion of IFN-γ and interleukin (IL)-17A, with negligible IL-10 and no IL-4, were detected in lymphocyte stimulation assays from both mORFV groups. No antibody responses to the mORFV platform were detected following immunisations. Conclusions: Both live and inactivated vaccines have the potential to be a platform technology for deployment in sheep. This addresses a notable gap in veterinary vaccine development where the induction of both humoral responses and cellular responses is required without using an adjuvant. The successful use of the MOMP candidate antigen suggests potential utility for bacterial disease deployment. Full article

Natural restoration of vegetation and plantation are effective land use measures to promote soil organic carbon (SOC) sequestration. How soil physicochemical properties, microorganisms, Glomalin-related soil proteins (GRSPs), and aggregates interact to regulate SOC accumulation and sequestration remains unclear. This study examined five land uses in the karst region of Southwest China: corn field (CF), corn intercropped with cabbage fields (CICF), orchard (OR), plantation (PL), and natural restoration of vegetation (NRV). The results revealed that SOC, total nitrogen (TN), total phosphorus (TP), total GRSP (T-GRSP), and easily extractable GRSP (EE-GRSP) contents were significantly higher under NRV and PL than in the CF, CICF, and OR, with increases ranging from 10.69% to 266.72%. Land use significantly influenced bacterial α-diversity, though fungal α-diversity remained unaffected. The stability of soil aggregates among the five land uses followed the order: PL > NRV > CF > OR > CICF. Partial least-squares path modeling (PLS-PM) identified land use as the most critical factor influencing SOC. SOC accumulation and stability were enhanced through improved soil properties, increased microbial diversity, and greater community abundance, promoting GRSP secretion and strengthening soil aggregate stability. In particular, soil microorganisms adhere to the aggregates of soil particles through the entanglement of fine roots and microbial hyphae and their secretions (GRSPs, etc.) to maintain the stability of the aggregates, thus protecting SOC from decomposition. Natural restoration of vegetation and plantation proved more effective for soil carbon sequestration in the karst region of Southwest China compared to sloping cropland and orchards. Full article

Background/Objectives: Listeria monocytogenes is a major foodborne pathogen responsible for listeriosis, a serious illness with high morbidity and mortality, particularly in vulnerable populations. Its persistence in food processing environments and resistance to conventional preservation methods pose significant food safety challenges. Lactic acid bacteria (LAB) offer a promising natural alternative due to their antimicrobial properties, especially through the production of bacteriocins. This study investigates the competitive interactions between Lactococcus lactis and L. monocytogenes under co-culture conditions, with a focus on changes in their secretomes to better understand how LAB-derived bacteriocins can help mitigate the Listeria burden. Methods: Proteomic approaches, including Tricine-SDS-PAGE, two-dimensional electrophoresis, and shotgun proteomics, were employed to analyze the molecular adaptations of both species in response to bacterial competition. Results: Our results reveal a significant increase in the secretion of enolase by L. monocytogenes when in competition with L. lactis, suggesting its role as a stress-responsive moonlighting protein involved in adhesion, immune evasion, and biofilm formation. Concurrently, L. lactis exhibited a shift in the production of its bacteriocin, nisin, favoring the expression of Nisin Z—a variant with improved solubility and diffusion properties. This differential regulation indicates that bacteriocin production is modulated by bacterial competition, likely as a defensive response to the presence of pathogens. Conclusions: These findings highlight the dynamic interplay between LAB and L. monocytogenes, underscoring the potential of LAB-derived bacteriocins as natural biopreservatives. Understanding the molecular mechanisms underlying microbial competition could enhance food safety strategies, particularly in dairy products, by reducing reliance on chemical preservatives and mitigating the risk of L. monocytogenes contamination. Full article

Background/Objectives: Acne vulgaris is a chronic skin infection characterized by high sebum secretion, keratosis around hair follicles, inflammation, and imbalance in androgen levels. Acne vulgaris causes permanent scars or skin pigmentation in cases of improper treatment. Oral or topical isotretinoin, contraceptives, and antibiotics are used to treat acne. Minocycline is one of the widely used tetracyclines for this purpose; it inhibits the synthesis of proteins in bacterial ribosomes. Commonly, minocycline is prescribed daily for several months for acne vulgaris. Systemic minocycline is highly distributed into body fluids, and it is associated with several side effects and antibiotic resistance. Additionally, minocycline is highly metabolized in the liver, leading to reduced bioavailability upon systemic delivery. This study aims to develop and characterize minocycline nanocrystals for targeted skin delivery and evaluate their antimicrobial efficacy in treating acne vulgaris. Methods: Minocycline nanocrystals were synthesized using milling or solvent evaporation techniques. Nanocrystals were characterized in terms of particle size, particle distribution index (PDI), zeta potential, and morphology. The antibacterial efficacy against Propionibacterium acne, Staphylococcus aureus, and Staphylococcus epidermidis was evaluated using a minimum inhibitory concentration assay (MIC) and agar well diffusion test in comparison to coarse minocycline. Results: Minocycline nanocrystals had a particle size of 147.4 ± 7.8 nm and 0.27 ± 0.017 of PDI. The nanocrystals exhibited a loading efficiency of 86.19 ± 16.7%. Antimicrobial testing showed no significant difference in activity between minocycline and its nanoparticle formulation. In terms of skin deposition, the nanocrystals were able to deliver minocycline topically to rat skin significantly more than free minocycline. The nanocrystal solution deposited 554.56 ± 24.13 μg of minocycline into rat skin, whereas free minocycline solution deposited 373.99 ± 23.32 μg. Conclusions: Minocycline nanocrystals represent a promising strategy for targeted skin delivery in the treatment of acne vulgaris, potentially reducing systemic side effects and antibiotic resistance and improving patient outcomes. Full article

The strain A-9^T, isolated from Oncorhynchus mykiss (rainbow trout) in a Turkish aquaculture facility, was characterized through integrated phenotypic, phylogenetic, and genomic analyses. Whole-genome sequencing revealed a 5.21 Mb circular chromosome (GC content: 58.16%) and three plasmids encoding proteins for mobilization and toxin–antitoxin systems. Multilocus phylogenetic analysis (MLPA) using seven housekeeping genes supported the distinct lineage of A-9^T. Digital DNA–DNA hybridization (77.6–78.6%) and average nucleotide identity values (96.59–97.58%) confirmed taxonomic divergence from all currently recognized A. salmonicida subspecies. Comparative proteomic and pangenomic analyses identified 328 strain-specific genes, including virulence factors, secretion system components (Type II and Type VI), and efflux-related proteins. Although genes encoding Type III secretion systems and biofilm formation were absent, A-9^T harbored a broad virulence gene repertoire and resistance determinants, including OXA-956, cphA5, and FOX-20, supporting a multidrug-resistant phenotype. Based on its genomic, phenotypic, and functional distinctiveness, we propose the novel taxon Aeromonas salmonicida subsp. oncorhynchi subsp. nov. (type strain A-9^T = LMG 33538^T = DSM 117494^T), expanding the taxonomic landscape of the A. salmonicida complex and offering insights into fish-associated bacterial evolution. Full article

Extracellular vesicles (EVs) are nanometer-sized lipid structures actively secreted by Gram-negative and Gram-positive bacteria, representing a sophisticated microbial adaptation and communication strategy. These structures are involved in biomolecular transport, the regulation of biological processes, the modulation of host–pathogen interactions, and adaptation to hostile environmental conditions. EVs also play a crucial role in virulence, antibiotic resistance, and biofilm formation. This review will explore the biogenesis, composition, and biological mechanisms of outer membrane vesicles (OMVs) secreted by Gram-negative bacteria and membrane vesicles (MVs) generated by Gram-positive bacteria. In detail, the modulation of EVs in response to antibiotic exposure will be addressed. The role of EV morpho-functional adaptations will be studied in antimicrobial resistance, the gene determinant spread, and survival in adverse environments. This study aims to provide a comprehensive overview of the EV role in bacterial physiology, highlighting their ecological, evolutionary, and biotechnological implications. An overview of the enzymes and proteins mainly involved in OMV-mediated resistance mechanisms will also be provided. These insights could open new perspectives for developing therapeutic strategies that counteract EV secretion and biotechnological applications, such as vaccines and drug delivery systems. Full article

Introduction: Recent studies have shown that Erythroid progenitor cells exhibit a distinct immunosuppressive and immunoregulatory phenotype associated with the response to bacteria. Methods: The objective of this study was to comprehensively explore the traits of human bone marrow Erythroid cells through protein–protein interaction network analysis using cytokine secretion analysis, and single-cell immunoproteomic analysis using flow cytometry, as well as the re-analysis of publicly available human and mouse bone marrow Erythroid-cell transcriptomic data. Results: Our protein–protein interaction network analysis of human bone marrow Erythroid-cell protein-coding genes identified enrichment in the immune response to lipopolysaccharide, with Calprotectin and Cathepsin G being the main factors. We then mapped the Calprotectin to the CD45⁺ Erythroid cells of both humans and mice via the analysis of the publicly available scRNA-seq data. Additionally, we observed that human bone marrow Erythroid cells secrete cytokines and chemokines, such as IL-1b, IL-8, and IL-18, which are also mainly involved in the immune response to lipopolysaccharide. We also found that human and mouse bone marrow Erythroid-cell conditional media inhibit bacterial growth in vitro. Discussion: These findings suggest that both human and mouse bone marrow CD45⁺ Erythroid cells possess the potential to combat pathogenic microbes and thus play a role in innate antimicrobial immunity. Conclusions: CD45⁺ Erythroid cells are a potent immunoregulatory cell population in both humans and mice. Full article

The aim of this study was to achieve the high secretion and expression of thymosin β4 derived from Pinctada fucata in Pichia pastoris, as well as to investigate its antibacterial properties and biological effects in promoting wound healing. The recombinant thymosin β4 protein (rTβ4) exhibited no hemolytic activity on rabbit red blood cells and demonstrated significant antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), with a minimum inhibitory concentration (MIC) of 25 μg/mL. It effectively inhibited bacterial growth and disrupted the cell wall and membrane structure of the bacteria. In the Sprague Dawley (SD) rat wound healing model, the wound healing rate in the rTβ4 treatment groups (at concentrations of 12.5 and 25 μg/mL) was significantly higher than that in the control group (p < 0.05), and the healing effect was comparable to that of the positive control group (Kangfu Xin solution, KFX). The histopathological study demonstrated that rTβ4 could reduce the infiltration of inflammatory cells and promote the proliferation and re-epithelialization of granulation tissue. In conclusion, this study successfully achieved the high expression of thymosin β4 derived from Pinctada fucata in Pichia pastoris and validated its antibacterial and wound healing potential through both In vitro and In vivo experiments. Full article