Folia microbiologica最新文献

The escalating crisis of antibiotic resistance presents a formidable challenge to global public health and food security. Insects are increasingly recognized as significant reservoirs and vectors for antibiotic resistance genes (ARGs) which inhabit diverse ecosystems. This review explores how the insect gut microbiota contributes to the development and spread of antibiotic resistance, focusing on the mediating role of the host immune system. We outline the structural and functional dynamics of the insect gut microbiome and elaborate on direct mechanisms through which microbiota contribute to resistance, including ARG carriage, enzymatic inactivation of antibiotics, and modulation of host detoxification pathways. Special emphasis is placed on the bidirectional crosstalk between gut microbes and the host immune system: we discuss how immune effectors, particularly antimicrobial peptides (AMPs), exert selective pressures that may enrich resistant taxa, and how microbial metabolites reciprocally regulate immune activity. Key immune signaling pathways-Toll, Immune Deficiency(Imd), and Janus kinase-signal transducer and activator of transcription (JAK-STAT)-are explored for their roles in maintaining microbial homeostasis and modulating resistance phenotypes. We also highlight cutting-edge experimental approaches, including gnotobiotic models and multi-omics technologies, that are essential for elucidating causal relationships. We conclude by highlighting outstanding questions and outlining future research priorities that integrate microbiology, immunology, and computational biology. This review aims to establish a holistic framework for understanding the insect gut as a hotspot for antibiotic resistance evolution and to inspire innovative microbiome-based interventions.

The industrial production of spirulina (Spirulina and Arthrospira spp.) demands large amounts of carbon and nitrogen. This becomes challenging as raw material costs increase and the worldwide market shifts toward organic products. In this study, we examined the feasibility and effectiveness of various carbon and nitrogen sources in both helical and linear spirulina cultures. Glucose at 2.5 g/L doubled the growth of linear spirulina, and the trichomes were 50% longer and thicker compared to the control (inorganic carbon). In addition, the obtained biomass contained more protein (95% ± 0.2%) and phycobiliproteins (PBPs) (989 ± 12 mg/g). The helical strain preferred a lower glucose concentration (0.5 g/L), which led to a twofold increase in protein content (77% ± 0.4%). On the other hand, the substitution of NaNO₃ with 1% soybean hydrolysate significantly increased the trichome size (500 μm ± 21.34 μm) and PBPs content (847.78 ± 143.9 mg/g) in the linear strain. When cultivated with 0.05% whey or soybean hydrolysate, the helical strain showed a 3.5-fold increase in protein content and a twofold increase in C-phycocyanin and PBPs levels. These findings highlight the robustness of the linear strain, which efficiently used higher organic inputs, whereas the helical strain responded better to lower concentrations of organic C and N.

The widespread emergence of multidrug-resistant pathogenic bacteria across various environments, healthcare settings, and food industries, combined with the development of new methods to combat them, highlights the need for more precise, rapid, and cost-effective pathogen detection techniques. This is especially important for clinically relevant pathogens, as it allows treatment to begin as quickly as possible, enables more effective targeted therapies to be chosen, helps preserve the effectiveness of current antibacterial agents, and prevents infections from water- and foodborne bacterial pathogens. Currently, many methods can accurately identify bacteria at the species or strain level and determine their antibiotic resistance. However, most of these techniques require sample preparation and cell culture beforehand, which can be time-consuming and labor-intensive. This review aims to highlight approaches that focus on identifying bacterial cells-especially pathogenic groups-based on their surface properties. This includes agents such as antibodies, whole phage particles, phage receptor binding proteins, cell wall-binding domains of peptidoglycan hydrolases, and functionalized magnetic nanoparticles. These agents can bind to and recognize peptidoglycan, parts of it, and other cell wall components. Developing detection kits based on these agents could enable the rapid detection of pathogenic bacteria from genera such as Acinetobacter, Bacillus, Campylobacter, Clostridium, Enterococcus, Klebsiella, Listeria, Pseudomonas, Salmonella, Shigella, Staphylococcus, Streptococcus, Vibrio, and Yersinia. These methods also offer the potential to distinguish these infectious pathogens from each other and from bacteria of the natural microbiota. Detection typically takes from a few minutes to several hours, with a broad detection range depending on the pathogen species, the detecting agent, and the technique used.

Ventilator-associated pneumonia (VAP) is the most common infection encountered in intensive care units and is closely linked with elevated mortality, morbidity, and healthcare expenditure. The predominant pathogens responsible for VAP are multidrug-resistant (MDR) Gram-negative bacteria, including Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli. This study aimed to investigate the molecular antibiotic resistance profiles of bacterial isolates from hospital-acquired VAP cases. Conducted between 30 November 2022 and 30 November 2023 at Kırşehir Training and Research Hospital, resistance genes were identified using Polymerase Chain Reaction (PCR), while clonal relatedness and genotyping were assessed through Repetitive Extragenic Palindromic-PCR (rep-PCR) and Multi-Locus Sequence Typing (MLST). The most frequently isolated organisms were A. baumannii (46.2%), K. pneumoniae (42.3%), and P. aeruginosa (7.7%). A. baumannii strains exhibited 100% resistance to ciprofloxacin and carbapenems, and 70.83% to colistin. K. pneumoniae strains demonstrated 94.73% resistance to carbapenems and 100% to piperacillin-tazobactam and colistin. Molecular analyses identified bla_TEM, bla_OXA-1, bla_CTX-M1, bla_OXA-51, bla_OXA-23, and bla_OXA-40 in A. baumannii, and bla_TEM, bla_SHV, bla_CTX-M1, bla_OXA-1, bla_OXA-48, and bla_NDM-1 in K. pneumoniae. Nine isolates (17%) were identified as transconjugants. MLST analysis revealed K. pneumoniae ST2096 and A. baumannii ST2 as predominant. Clones not previously reported in Türkiye A. baumannii ST78 and K. pneumoniae ST45, ST437, and ST1128 were also detected. This study provides a comprehensive molecular characterisation of VAP pathogens based on an extensive dataset. The results underscore the need for stricter infection control, restrained use of broad-spectrum antibiotics, and ongoing surveillance of resistance mechanisms.

Epstein-Barr virus (EBV) is a ubiquitous human herpesvirus that establishes lifelong latency in its host and is associated with a range of malignancies and immune-related disorders. This review examines the complex interactions between EBV and microRNAs (miRNAs), small, non-coding RNAs that regulate gene expression at the post-transcriptional level. It focuses on EBV-encoded miRNAs derived from the BHRF1 and BART clusters, detailing their distinct functions during different latency phases and viral reactivation. These miRNAs facilitate immune evasion, modulate cell cycle progression, apoptosis, and differentiation, and promote cellular environments that favor viral persistence and oncogenesis. EBV also disrupts host miRNA networks, altering gene expression and immune regulation, which contributes to tumor development in diseases such as Burkitt's lymphoma, nasopharyngeal carcinoma, Hodgkin's lymphoma, and post-transplant lymphoproliferative disorders, and has additionally emerged as a leading etiological factor in multiple sclerosis. Furthermore, the review highlights how viral and host miRNAs jointly modulate immune checkpoints, antiviral defense mechanisms, and the tumor microenvironment. It concludes by summarizing recent progress in miRNA-based diagnostics and therapeutics, underscoring their potential for advancing personalized medicine in EBV-associated pathologies.

This study aimed to isolate acid-tolerant lactic acid bacteria from Suancai, a traditional Chinese fermented vegetable, and evaluate their potential and safety as candidate probiotics. Fifteen dominant lactic acid bacteria strains were isolated from spontaneously fermented Suancai, and four isolates were selected based on their tolerance to acid and bile, as well as their autoaggregation, coaggregation, cell surface hydrophobicity, and adhesion capabilities. Based on 16S rRNA and pheS gene sequence analyses, the four strains were identified as Lactiplantibacillus plantarum (strain S5) and Levilactobacillus brevis (strains S1, H1, and H2). These strains were further evaluated for multiple in vitro probiotic properties. All four exhibited cholesterol removal capacity, DPPH and hydroxyl radical scavenging activity, gamma-aminobutyric acid production, and nitrite degradation ability. α-Glucosidase inhibitory activity was observed in three strains, with the exception of Levilactobacillus brevis S1. Additionally, all strains displayed antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Salmonella paratyphi B. Safety assessment revealed that the strains were sensitive to ampicillin, erythromycin, and penicillin, resistant to gentamycin, and negative for indole production and hemolytic activity. In conclusion, the four selected strains demonstrated favorable probiotic characteristics and safety profile, supporting their potential as candidate probiotics for functional food application.

Antimicrobial resistance (AMR) is a mounting global health challenge projected to cause up to 10 million deaths annually by 2050. Despite advances in antibiotic discovery, the rapid emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) pathogens undermines modern medicine, threatening procedures such as surgery, chemotherapy, and organ transplantation. Conventional antibiotics face increasing limitations due to target-site mutations, efflux mechanisms, enzymatic degradation, and biofilm-associated tolerance, underscoring the urgent need for novel antimicrobial strategies. Phenazines, particularly 1-hydroxyphenazine (1-HP), represent promising alternatives owing to their redox activity, broad-spectrum antimicrobial properties, and ecological roles in microbial competition. Recent advances highlight the potential of 1-HP as both a virulence factor and a therapeutic scaffold, with applications spanning agriculture, biotechnology, and medicine. Synthetic biology, metabolic engineering, and nanocarrier-based delivery systems have enabled scalable production and reduced toxicity, while structural modifications such as halogenation have expanded therapeutic potential. This review consolidates historical, mechanistic, and translational insights into 1-HP, emphasizing its dual role as a pathogenic metabolite and a lead compound for future antimicrobial and anticancer development.

The endophytic isolate PAD5, derived from Eryngium foetidum L. and identified as Bacillus pumilus strain PAD5 (KX350056), demonstrated remarkable characteristics including phosphate solubilization (7.5 µg/ml), indole-3-acetic acid (IAA) production (31.13 µg/ml), biofilm formation, siderophore, hydrogen cyanide (HCN), and exo-polysaccharide production. It exhibited robust growth on nitrogen-free media, high salt conditions (6%), and low pH (5.0). The isolate showed potent antagonistic activity against Sclerotium rolfsii. Gas chromatography-mass spectrometry (GC-MS) analysis of the crude extract revealed the presence of five major and 19 minor active compounds. When applied in conjunction with the pathogen (SrBp), the PAD5 isolate remarkably enhanced rice growth after 20 days of transplanting, recording substantial increases over the pathogen (Sr) treatment shoot length by 175.8%, shoot fresh weight by 193.5%, shoot dry weight by 161.0%, root length by 106.5%, root fresh weight by 114.3%, and root dry weight by 129.2%. These pronounced improvements indicating PAD5's strong potential in promoting plant growth even under pathogen-induced stress. Additionally, the PAD5 isolate induced systemic response and enhanced host defense physiological activities, as evidenced by elevated plant defense enzyme such as Phenylalanine ammonia lyase (PAL), Total phenol content (TPC), Polyphenol oxidase (PPO), and Superoxide dismutase (SOD) enzyme activities in seedlings treated with either isolate PAD5 alone or in combination with the pathogen (SrBp).

Cancer continues to be a leading cause of death globally, driving the ongoing search for novel bioactive compounds with therapeutic potential. Metagenomic sequencing has revolutionized this pursuit by enabling the direct detection and genomic assembly of previously uncultured Streptomyces species from environmental DNA, circumventing traditional cultivation limitations. This review explores recent advances in metagenomics-driven discovery of anticancer compounds derived from Streptomyces, with a focus on identifying biosynthetic gene clusters (BGCs) responsible for producing bioactive secondary metabolites. Over the past decade, metagenomic approaches have been adopted to uncover new species of Streptomyces and anticancer compounds. Although metagenomics has been adopted in research and discovery of new Streptomyces, its application in the discovery of Streptomyces-related pathways pertaining to anticancer compounds remains limited. Furthermore, clinical translation remains limited, highlighting the need for further research. By examining metagenomic methodologies and the mechanisms of action of these compounds, this review provides an updated and focused perspective on Streptomyces-derived anticancer agents and their potential for future drug development.

β-Glucans, naturally occurring β-D-glucose polysaccharides from fungi, yeast, bacteria, algae, and cereals, have emerged as promising immunomodulatory agents in antiviral defense. Their structural diversity-encompassing β-1,3, β-1,6, and β-1,4 linkages-underpins varied solubility, bioavailability, and biological activity, driving their therapeutic potential. Unlike conventional antivirals that target viral replication, β-glucans enhance host immunity by activating innate and adaptive responses through receptors such as dectin-1, toll-like receptors, and complement receptor 3, thereby stimulating macrophages, neutrophils, and natural killer cells to produce antiviral cytokines (e.g., interferons, interleukins) and induce trained immunity for long-term protection. This review explores β-glucans's mechanisms in combating viral infections, including SARS-CoV-2, HPV, HBV, influenza, and HIV, highlighting direct antiviral effects (e.g., inhibiting viral entry via sulfated derivatives), immune modulation (e.g., enhancing T-cell responses and antibody production), and inflammation control (e.g., mitigating cytokine storms). Preclinical and clinical evidence underscores their ability to reduce viral load, enhance vaccine efficacy, and support tissue repair, as seen in HPV-related lesions. β-Glucans also modulate the gut microbiota, bolstering mucosal immunity. Despite promising outcomes, challenges like structural heterogeneity and limited large-scale trials persist. This article outlines the therapeutic prospects of β-glucans, emphasizing their potential as safe and versatile adjuncts to address emerging viral threats and enhance global health resilience.