Search Results (726)

Background: The aim of this review is to summarize and evaluate the properties of antibacterial polysaccharides for application in dental implantology to identify knowledge gaps and provide new research ideas. Methods: The electronic databases PubMed, Medline, ProQuest, and Google Scholar were used to search for peer-reviewed scientific publications published between 2018 and 2025 that provide insights to answer research questions on the role of antibacterial polysaccharides in combating pathogens in dental implantology without triggering immune reactions and inflammation. Further research questions relate to the efficacy against various dental pathogens and the understanding of the antibacterial mechanism, which may enable the development of functionalized polysaccharides with long-term antibacterial activity. Results: Biomedical implants have revolutionized medicine but also increased the risk of infections. Implant infections are a major problem in implantology and lead to implant failure and replacement. An antibacterial coating could be an excellent strategy to extend the lifespan of implants and improve the quality of the patient’s life. Bacterial resistance to antibiotics poses significant challenges for researchers, forcing them to search for new ways to prevent bacterial infections in implantology. Antibacterial natural polymers have recently received considerable research attention due to their long-term antibacterial activity. Polysaccharides from marine sources, such as chitosan and alginate, or pectin, xanthan, etc., from various plants, appear to be promising biopolymers for such applications in implantology due to their antibacterial activity, biocompatibility, and osteogenic properties. The antibacterial activity of these natural biopolymers depends on their chemical and physical properties. Nanopolysaccharides exhibit higher antibacterial activity than conventional polysaccharides, but their toxicity to human cells must be considered. Their antibacterial activity is based on the disruption of bacterial DNA or RNA synthesis, increased cell wall permeability, membrane disruption, and cytoplasmic leakage. Conclusions: Polysaccharides are a class of natural polymers with a broad spectrum of biological activities. They exhibit antioxidant, immunomodulatory, anticoagulant, anticancer, anti-inflammatory, antibacterial, and antiviral activity. Furthermore, polysaccharides are non-cytotoxic and exhibit good biocompatibility with osteogenic cells. Bactericidal polysaccharides are attractive new antibacterial materials against implant infections and open up new perspectives in implantology. Full article

Methicillin-resistant Staphylococcus aureus (MRSA), a multidrug-resistant pathogen, poses a significant threat to global healthcare. This review evaluates the potential of marine algal metabolites as novel antibacterial agents against MRSA. We explore the clinical importance of S. aureus, the emergence of MRSA as a “superbug”, and its resistance mechanisms, including target modification, drug inactivation, efflux pumps, biofilm formation, and quorum sensing. The limitations of conventional antibiotics (e.g., β-lactams, vancomycin, macrolides) are discussed, alongside the promise of algal-derived compounds such as fatty acids, pigments, polysaccharides, terpenoids, and phenolic compounds. These metabolites exhibit potent anti-MRSA activity by disrupting cell division (via FtsZ inhibition), destabilizing membranes, and inhibiting protein synthesis and metabolic pathways, effectively countering multiple resistance mechanisms. Leveraging advances in algal biotechnology, this review highlights the untapped potential of marine algae to drive innovative, sustainable therapeutic strategies against antibiotic resistance. Full article

Antimicrobial resistance (AMR) has emerged as a global health crisis, with methicillin-resistant Staphylococcus aureus (MRSA) representing one of the most clinically significant multidrug-resistant pathogens. In this study, three structurally unique anthracycline derivatives—keto-ester (1), 4-deoxy-ε-pyrromycinone (2), and misamycin (3)—were first isolated and characterized from the fermentation broth of the marine-derived Streptomyces tauricus NBUD24. These compounds exhibited notable antibacterial efficacy against MRSA, with minimum inhibitory concentrations (MICs) ranging from 16 to 32 µg/mL. Cytotoxicity assays confirmed their safety profile at therapeutic concentrations. The biofilm formation assay demonstrated that 4-deoxy-ε-pyrromycinone inhibited biofilm formation of MRSA ATCC43300, with an inhibition rate of 64.4%. Investigations of antibacterial mechanisms revealed that these compounds exert antibacterial effects primarily through disruption of bacterial cell wall integrity and destruction of DNA structure. These findings underscore the potential of marine-derived microbial metabolites as promising scaffolds for developing next-generation antimicrobial candidates to combat drug-resistant infections. Full article

Microplastic particles (MPs) are an emerging global pollutant of increasing concern due to their widespread occurrence, persistence, and multifaceted impact on aquatic ecosystems. This study provides a comprehensive review of peer-reviewed literature from 2011 to 2025, analysing the presence, distribution, and microbiological associations of MPs in surface waters across five continents. The findings confirm that MPs are present in both marine and freshwater systems, with concentrations varying by region, hydrology, and proximity to anthropogenic sources. Polyethylene and polypropylene were identified as the most common polymers, often enriched in river mouths, estuaries, and aquaculture zones. A key focus of this review is the plastisphere—microbial biofilms colonizing MPs—which includes both environmental and pathogenic bacteria such as Vibrio, Pseudomonas, and Acinetobacter. Notably, MPs serve as vectors for the spread of antibiotic resistance genes (ARGs), including sul1, tetA and ermF, and β-lactamase genes like blaCTX-M. This highlights their role in enhancing horizontal gene transfer and microbial dissemination. The results emphasize the need for standardized monitoring protocols and further interdisciplinary research. In light of the One Health approach, understanding the microbial dimension of MP pollution is essential for managing risks to environmental and public health. Full article

Vibrio parahaemolyticus is a pathogenic bacterium widely distributed in marine environments, posing significant threats to aquatic organisms and human health. The overuse and misuse of antibiotics has led to the development of multidrug- and pan-resistant V. parahaemolyticus strains. There is an urgent need for novel antibacterial therapies with innovative mechanisms of action. In this work, a genome-scale metabolic network model (GMSN) of V. parahaemolyticus, named VPA2061, was reconstructed to predict the metabolites that can be explored as potential drug targets for eliminating V. parahaemolyticus infections. The model comprises 2061 reactions and 1812 metabolites. Through essential metabolite analysis and pathogen–host association screening with VPA2061, 10 essential metabolites critical for the survival of V. parahaemolyticus were identified, which may serve as key candidates for developing new antimicrobial strategies. Additionally, 39 structural analogs were found for these essential metabolites. The molecular docking analysis of the essential metabolites and structural analogs further investigated the potential value of these metabolites for drug design. The GSMN reconstructed in this work provides a new tool for understanding the pathogenic mechanisms of V. parahaemolyticus. Furthermore, the analysis results regarding the essential metabolites hold profound implications for the development of novel antibacterial therapies for V. parahaemolyticus-related disease. Full article

Microbial infections are an escalating global health threat, driven by the alarming rise of antimicrobial resistance (AMR), which has made many conventional antibiotics increasingly ineffective and threatens to reverse decades of medical progress. The rapid emergence and spread of multidrug-resistant bacteria have severely limited treatment options, resulting in increased morbidity, mortality, and healthcare burden worldwide. In response to these challenges, phage therapy is regaining interest as a promising alternative. Bacteriophages, the most abundant biological entities, have remarkable specificity toward their bacterial hosts, enabling them to selectively eliminate pathogenic strains. Phage therapy presents several advantages over conventional antibiotics, which include minimal disruption to the microbiome and a slower rate of resistance development. Among the various sources of phages, the marine environment remains one of the least explored. Given their adaptation to saline conditions, high pressure, and variable nutrient levels, marine bacteriophages mostly exhibit enhanced environmental stability, broader host ranges, and distinct infection mechanisms, thus making them highly promising for therapeutic purposes. This review explores the growing therapeutic potential of marine bacteriophages by examining their ecological diversity, biological characteristics, infection dynamics, and practical applications in microbial disease control. It also deals with emerging strategies such as phage–antibiotic synergy, genetic engineering, and the use of phage-derived enzymes, alongside several challenges that must be addressed to enable clinical translation and regulatory approval. Advancing our understanding and application of marine phages presents a promising path in the global fight against AMR and the development of next-generation antimicrobial therapies. Full article

Microplastics are pervasive in marine ecosystems and have been shown to affect a range of marine organisms, including corals. These particles can develop biofilms, facilitating the transport of pollutants and pathogenic microorganisms. Although the effects of primary microplastics on adult corals have been extensively studied, little is known about the impacts of secondary microplastics on early life stages. This study investigated (1) the effects of different abundances of secondary microplastics on the early development of Orbicella faveolata; (2) the influence of fibers and fragments on the larval settlement of Acropora palmata; and (3) the effects of the microplastic size, abundance, and biofilm presence on the settlement of Favia fragum. For O. faveolata, fertilization, embryogenesis, and settlement were all impaired by fragments, with embryonic development showing a 25.9% reduction in viability. Larval development was unaffected, but post-settlement survival declined by 35.8% with exposure to fibers and fragments. For A. palmata, settlement was reduced by fragments, while for F. fragum, only 2–4 mm fragments significantly decreased settlement rates. This study contributes to the knowledge of the effect of microplastics on the early development of corals, providing valuable information to improve strategies to control microplastic pollution. Full article

Aquatic resistomes are important reservoirs of antibiotic resistance genes (ARGs) and their precursors, which can proliferate and dissipate in pathogenic microorganisms that affect humans and animals, especially due to anthropogenic pressures such as the intensive use of antibiotics in aquaculture, often without effective regulation. This review addresses the mechanisms of horizontal gene transfer (HGT) in the dissemination of ARGs through mobile genetic elements (MGEs). In freshwater, genera such as Aeromonas, Pseudomonas and Microcystis stand out as vectors of ARGs. In the context of One Health, it is essential to implement sound public policies and strict regulations on the use of antibiotics in aquaculture, and the use of monitoring tools such as environmental DNA (eDNA) and metagenomics allows for the early detection of ARGs, contributing to the protection of human, animal and environmental health. Full article

A key feature that differentiates Gram-positive and Gram-negative bacteria is the outer membrane, an asymmetric membrane composed of lipopolysaccharides, phospholipids, lipoproteins and integral proteins, including the outer-membrane proteins (OMPs). By being in direct contact with the extracellular milieu, the outer membrane and OMPs participate in multiple functions in Gram-negative bacteria, including controlling nutrient and molecule access to the cytoplasm, membrane vesicle formation and resistance to environmental stresses. OMPs have a characteristic barrel shape formed by antiparallel β-strands, with or without channels that allow diffusion of substrates through the outer membrane. The marine bacterium Vibrio cholerae is responsible for non-invasive gastroenteritis and cholera disease by consumption of contaminated water or food. Its OMPs, besides having a porin function, contribute to resistance to osmotic pressure and antimicrobial agents, intracellular signaling, adhesion to host cells and biofilm formation, amongst other functions. In this review, in addition to quickly reviewing the general structure of the outer membrane, the OMPs and how they reach the outer membrane, the functions attributed to these proteins are compiled. The mechanisms used by each of the described OMP to accomplish these functions in the marine pathogenic bacterium V. cholerae are discussed. Potential clinical and bioengineering applications of OMPs, such as diagnostic tools, vaccine development, and targeted antimicrobial or anti-virulence strategies are presented. What is known about the OMPs of V. cholerae is presented below. Full article

Tuberculosis (TB) poses a persistent global health threat exacerbated by the emergence of drug-resistant strains; hence, there is a continuous quest for novel antimicrobial agents. Despite efforts to develop effective therapies, existing treatments require a relatively long duration of therapy to eradicate the pathogen due to its virulence factors, pathogenesis patterns, and ability to enter dormant states. This can lead to a higher risk of treatment failure due to poor patient adherence to the complex regimen. As a result, considerable research is necessary to identify alternative antituberculosis agents. The marine environment, particularly marine-derived fungi, has recently gained interest due to its potential as an abundant source of bioactive natural products. This review covers 19 genera of marine-derived fungi and 139 metabolites, 131 of which exhibit antimycobacterial activity. The integrated dataset pinpoints the fungal genera and chemical classes that most frequently yield potent antimycobacterial hits while simultaneously exposing critical gaps, such as the minimal evaluation of compounds against dormant bacilli and the presence of underexplored ecological niches and fungal genera. Several compounds exhibit potent activity through uncommon mechanisms, including the inhibition of mycobacterial protein tyrosine phosphatases (MptpB/MptpA), protein kinase PknG, ATP synthase and the disruption of mycobacterial DNA via G-quadruplex stabilization. Structure–activity relationship (SAR) trends are highlighted for the most potent agents, illuminating how specific functional groups underpin target engagement and potency. This review also briefly proposes a dereplication strategy and approaches for toxicity mitigation in the exploration of marine-derived fungi’s natural products. Through this analysis, we offer insights into the potency and challenges of marine-derived fungi’s natural products as hit compounds or scaffolds for further antimycobacterial research. Full article

Vibrio species are among the primary pathogenic bacteria affecting abalone aquaculture, posing significant threats to farming practices. Current clinical control predominantly relies on antibiotics, which can result in antibiotic residues in both abalone and the surrounding marine environments. Lactobacillus plantarum (LP) has been shown to release bioactive antagonistic substances and exhibits potent inhibitory effects against marine pathogenic bacteria. This study aimed to screen and characterize the probiotic properties of LP strains isolated from rice wine lees to develop a novel biocontrol strategy against Vibriosis in abalone. The methods employed included selective media cultivation, streak plate isolation, and single-colony purification for strain screening, followed by Gram staining, 16S rDNA sequencing, and phylogenetic tree construction using MEGA11 for identification. The resilience, antimicrobial activity, and in vivo antagonistic efficacy of the strains were evaluated through stress tolerance assays, agar diffusion tests, and animal experiments. The results demonstrated the successful isolation and purification of four LP strains (NDMJ-1 to NDMJ-4). Phylogenetic analysis revealed closer genetic relationships between NDMJ-3 and NDMJ-4, while NDMJ-1 and NDMJ-2 were found to be more distantly related. All strains exhibited γ-hemolytic activity, bile salt tolerance (0.3–3.0%), and resistance to both acid (pH 2.5) and alkali (pH 8.5), although they were temperature sensitive (inactivated above 45 °C). The strains showed susceptibility to most of the 20 tested antibiotics, with marked variations in hydrophobicity (1.91–93.15%) and auto-aggregation (13.29–60.63%). In vitro antibacterial assays revealed that cell-free supernatants of the strains significantly inhibited Vibrio parahaemolyticus, V. alginolyticus, and V. natriegens, with NDMJ-4 displaying the strongest inhibitory activity. In vivo experiments confirmed that NDMJ-4 significantly reduced mortality in abalone infected with V. parahaemolyticus. In conclusion, the LP strains isolated from rice wine lees (NDMJ-1 to NDMJ-4) possess robust stress resistance, adhesion capabilities, and broad antibiotic susceptibility. Their metabolites exhibit significant inhibition against abalone-pathogenic Vibrios, particularly NDMJ-4, which demonstrates exceptional potential as a candidate strain for developing eco-friendly biocontrol agents against Vibriosis in abalone aquaculture. Full article

The parasitic dinoflagellate Hematodinium is an infectious pathogen that causes severe enzootic in numerous economically important marine crustaceans worldwide. Previous research has focused on investigating the identification and life stages of Hematodinium parasites, while the parasite abundance and tissue proliferation process of Hematodinium in naturally infected crustacean hosts need to be further studied. In the present study, the tissue tropisms and intensity of H. perezi were investigated in the naturally infected Chinese swimming crabs Portunus trituberculatus by both the qualitative (hemolymph assay, histology) and quantitative analysis (cell count, quantitative PCR). The results showed that in P. trituberculatus with infection level I (4 ± 2 parasites in 200× microscopic field), filamentous trophonts were observed in the hemolymph and stomach tissues, with the average parasite number and ITS 1 copy number of H. perezi quantitatively detected in hemolymph (1.0 × 10² parasites/mL) and stomach tissues (1.7 × 10³ cells/g), respectively. H. perezi trophonts were observed in the hemolymph (4.3 × 10⁴ parasites/mL) and exhibited broad distribution in multiple tissues with its highest abundance of H. perezi in pereiopod muscles (1.1 × 10⁴ cells/g) followed by that in stomach (4.8 × 10³ cells/g) in P. trituberculatus with infection level II (80 ± 10 parasites in 200× microscopic field). In P. trituberculatus with infection level III (200 ± 35 parasites in 200× microscopic field), a high abundance of H. perezi sporoblasts was found in the hemolymph (3.1 × 10⁷ parasites/mL) and all of the other examined tissues, with its highest abundance detected in pereiopod muscles (3.5 × 10⁴ cells/g). In addition, the number of host’s hemocytes was significantly decreased during the Hematodinium infection. This study provides a comprehensive quantitative characterization of the tissue distribution and abundance of H. perezi in its natural crab host which will contribute to better understanding of the crustacean host–Hematodinium interactions. 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

Necrotizing soft tissue infections (NSTIs) are serious and aggressive infections which can result in significant morbidity and mortality. Both prompt surgical intervention and early antibiotics can decrease patient mortality. Based on microbiology, NSTIs can be categorized into four different types. Type I is polymicrobial, caused by a mix of both anaerobic and aerobic bacteria. Type II is monomicrobial, usually caused by either Streptococcus or Staphylococcus. Type III infections are caused by Gram-negative bacteria, often marine-related organisms, such as Vibrio. Lastly, Type IV infections are caused by fungi, and they are often associated with trauma. Despite the possibility of all these different pathogens in NSTI, early therapy often consists of a broad Gram-positive antimicrobial such as linezolid or vancomycin, and a broad Gram-negative agent such as piperacillin/tazobactam. Multiple factors including patient comorbidities, environmental exposures, and clinical presentation must also be considered when choosing antimicrobial agents and dosing. Adjunct medical therapies such as intravenous immunoglobulin (IVIG) and the antibiotics clindamycin and linezolid that are aimed at toxin suppression may be utilized to improve outcomes. Microbiological data are critical for optimizing the antimicrobial regimen. Full article

In fish, the innate immune system is crucial for rapid defense against pathogens. In this study, we performed transcriptome sequencing using next-generation sequencing (NGS) to identify and characterize granulocyte colony-stimulating factor (GCSF) and macrophage colony-stimulating factor (MCSF) in starry flounder (Platichthys stellatus). The GCSF gene (594 bp, 198 aa) features a conserved IL-6 domain, while the MCSF gene (621 bp, 207 aa) contains a predicted transmembrane region. Phylogenetic analysis confirmed high evolutionary conservation with other marine species. Quantitative real-time PCR revealed that GCSF is highly expressed in the skin, peripheral blood leukocytes, and muscle, with significant up-regulation in immune organs following Streptococcus parauberis infection; MCSF exhibited a similar tissue-specific expression pattern. Recombinant GCSF (rGCSF) was produced using a cell-free system and effectively enhanced leukocyte phagocytic activity at an optimal concentration of 150 μg/mL, without causing cytotoxicity in hemolytic assays. In contrast, rMCSF exhibited folding issues during purification. These findings highlight the potential of rGCSF as a molecular adjuvant to enhance immune responses in aquaculture. This study provides foundational knowledge for developing cytokine-based adjuvants, which could reduce antibiotic dependency and enhance vaccine efficacy in sustainable aquaculture systems. Full article