Microorganisms最新文献

The world is divided into seven regional pools based on the serotype distribution and geographical spread of the foot-and-mouth disease (FMD) virus. The Republic of Korea (ROK) belongs to Pool 1, where serotypes O, A, and Asia1 are endemic. Recently, the risk of incursions by the O/CATHAY topotype has increased in Pool 1, raising concerns about its potential introduction into the ROK. To assess the protective effectiveness of three commercial FMD vaccine strains-O1/Manisa + O/3039, O/Primorsky, and O1/Campos-currently used in the ROK against this topotype, an animal challenge experiment was conducted. Three treatment groups (n = 4 in each) of pigs received a single 2 mL injection of one of the vaccines at 8-10 weeks of age, and the other group (n = 2) served as the control. All pigs were challenged with the O/HKN/5/2019 virus (O/CATHAY topotype) at 21 days post-vaccination. All vaccines conferred protective effects, with O1/Campos demonstrating the highest efficacy by inducing fewest clinical signs and significantly reducing virus shedding in the treated groups compared with those in the control group. These findings suggest O1/Campos may serve as an emergency measure; nevertheless, the development of a vaccine specifically targeting the O/CATHAY topotype is warranted.

Clostridium perfringens is one of the main causes of death in poultry with no vaccines approved for poultry at present. The appropriate adjuvant is critical for the development of vaccines in C. perfringens in poultry. Here, we utilized Levilactobacillus brevis for high-yielding selenium biotransformation and demonstrated that heat-inactivated nano-selenium Lactobacillus (HiSeL) is a safe, efficient, and chemically stable selenium immunopotentiator for C. perfringens vaccines. We evaluated the effectiveness of HiSeL as an immune adjuvant to modulate the efficacy of multi-epitope vaccine in mice. Subcutaneous immunization mice with HiSeL promoted high levels of specific IgG, modulated cytokine secretion, downregulated stress-related gene expression, and provided 100% protection against lethal challenge with C. perfringens. Surprisingly, we found that HiSeL can quickly and effectively induce SIgA production even by subcutaneous immunization. Transcriptome sequencing revealed the pivotal role of TGF-β and NF-κB signaling pathways in IgA immune responses in mice immunized with the HiSeL-adjuvanted multi-epitope vaccine. Collectively, our study provides proof-of-concept evidence that HiSeL functions as a potent adjuvant candidate for the multi-epitope vaccine in a murine model, offering new insights into the development of engineered postbiotic-based adjuvants.

Subcutaneous mycoses are a heterogeneous group of chronic fungal infections, usually acquired through traumatic inoculation of environmental fungi and particularly severe in immunocompromised and critically ill patients. These infections involve pathogens with marked morphological and physiopathological diversity, resulting in significant diagnostic and therapeutic challenges. Conventional treatment relies on systemic antifungals such as amphotericin B, itraconazole, and other azoles; however, these therapies are often limited by poor tissue penetration, adverse effects, and prolonged treatment regimens, especially in vulnerable patient populations. In this context, nanodrugs have emerged as promising alternatives by improving solubility, stability, bioavailability, and targeted delivery to infection sites. This review conducted a comprehensive literature search in PubMed, SciELO, ScienceDirect, Web of Science, and Scopus, identifying 31 eligible studies that developed and evaluated antifungal nanosystems using in vitro, ex vivo, and/or in vivo models. Quantitative outcomes included minimum inhibitory concentration (MIC), colony-forming units (CFU), inhibition halo diameter, and survival assays. Overall, the evidence indicates that several nanosystems may overcome key pharmacological limitations of conventional antifungals and enhance therapeutic outcomes. Nevertheless, important translational challenges remain, including toxicity, long-term safety, scalability, and regulatory approval, which must be addressed before clinical implementation.

The oral microbiome of patients with acute lymphoblastic leukemia (ALL) undergoes changes caused by the neoplasia as well as the antimicrobial activity of chemotherapy (CTX), which promotes the development of oral mucositis (OM). This study aimed to analyze the oral microbiome dynamics and salivary cytokine production in pediatric ALL patients before and during CTX, comparing children who did and did not develop OM. We conducted a longitudinal, observational, and analytical study including 32 newly diagnosed pediatric ALL patients (ages 2-16 years) undergoing CTX. Oral rinse and non-stimulated saliva samples were collected at baseline (day 0), day 14, and day 21 of induction of CTX, with an additional sample taken during OM episodes when possible. Microbiome analysis was performed using 16S rRNA sequencing on an Illumina MiSeq platform, and salivary cytokines were measured using a Luminex multiplex assay. The most pronounced microbiome changes occurred on day 14, particularly in patients who developed OM, characterized by higher α diversity, increased abundance of opportunistic taxa, and elevated IL-6 concentrations. In contrast, patients who did not develop OM exhibited a more stable microbial composition. Overall, these findings indicate that temporal oral dysbiosis and increased IL-6 may serve as early markers and potential predictors of OM development during chemotherapy in pediatric ALL patients.

This study aimed to investigate the chemical composition and biological potential of needle extracts from five pine species, including antimicrobial, antioxidant, and cytotoxic activity, as well as their influence on cell cycle progression. Needle extracts were prepared using three extraction methods: conventional maceration (CM), ultrasound-assisted extraction (UAE), and digestion (D). The chemical profile was determined with an emphasis on phenolic acids, flavonoids, and related phenolic compounds. The highest total phenolic content was observed in Pinus sylvestris (3.438 mg/g GAE), followed by Pinus heldreichii (2.732 mg/g GAE). Rutin, ferulic acid, and quercitrin were identified as the predominant phenolic compounds. The highest total flavonoid content was found in Pinus pinea extracts obtained by digestion (1.213 mg/g QE), followed by P. heldreichii (1.074 mg/g QE) and Pinus halepensis (1.074 mg/g QE), both obtained by UAE. Among all examined species, Pinus pinea exhibited the highest TTC values, regardless of the extraction method (7.31-8.21 mg/g GAE). Antibacterial testing showed that P. pinea had an MIC of 19 mg/mL against Enterococcus faecium, while P. sylvestris had the same MIC against Bacillus spizizenii. All extracts exhibited cytotoxic effects using MTT assay against HeLa cells at concentrations of 8%, 16%, and 32%, while LS 174T cells were the least sensitive. Pine needle extracts from Montenegro are a valuable source of phenolic and flavonoid compounds, and they demonstrate antimicrobial and cytotoxic activities. The results support the need for further in vivo studies and elucidation of mechanisms of action in order to assess their potential application as novel bioactive agents.

Orchid seed germination requires symbiotic association with mycorrhizal fungi that provide essential nutrients for germination and subsequent growth. Extensive research has elucidated the pivotal role of the mycorrhizal fungus Tulasnella sp. in the modulation of seed germination and growth processes in Bletilla striata (Thunb.) Reiehb.f. However, the molecular mechanisms underlying this symbiosis remain poorly characterized. Our integrated transcriptomic-metabolomic analysis of symbiotic germination revealed that co-cultivation of Tulasnella sp. bj1 with B. striata seeds significantly downregulates the expression of plant-derived flavonoid biosynthetic genes, with flavonoid degradation potentially alleviating germination and growth inhibition. The bj1 strain modulates indoleacetic acid (IAA) biosynthesis in B. striata by upregulating the expression of plant-derived tryptophan decarboxylase (TDC) in the tryptophan pathway and hydrolytic enzymes (NtAMI) in the indoleacetamide pathway, with elevated IAA potentially contributing to seed germination and growth. Moreover, bj1 suppresses the jasmonic acid (JA) biosynthetic pathway of B. striata by downregulating key plant-derived biosynthetic genes, concurrently promoting the accumulation of 12-hydroxyjasmonic acid-a metabolite associated with plant immune regulation that may favor colonization and symbiotic establishment with B. striata seeds. Additionally, bj1 induces the expression of polysaccharide-degrading enzymes, potentially improving carbon source utilization to support protocorm development. In conclusion, bj1 modulates the immune response of B. striata seeds, facilitating the establishment of a symbiotic relationship. Subsequently, the germination and growth of B. striata seeds are enhanced through reduced flavonoid accumulation, increased IAA synthesis, and improved carbon source utilization. Consequently, this investigation provides a crucial foundation for elucidating mechanisms governing symbiotic germination in B. striata.

Urease-producing bacteria (UPB) have great potential for the bioremediation of heavy-metal pollution through biomineralization and adsorption. In this study, a strain of UPB, C7-12, was isolated from heavy-metal-contaminated soil in a lead-zinc mining area and identified as Serratia marcescens. The heavy-metal removal ability, influencing factors, and precipitation mode of this UPB strain in solution were investigated. The cadmium (Cd) removal rate in a Cd (1 mg/L) solution from C7-12 reached 85%, and pH was the main influencing factor. With urea mediation, S. marcescens C7-12 biomineralizes the Cd²⁺ in solution to form CdCO₃ and removes it through extracellular precipitation and surface adsorption. Furthermore, the removal rates of Cd²⁺, Pb²⁺, Zn²⁺ and Cu²⁺ in solution by S. marcescens C7-12 were 33-65%, 28-32%, 22-49%, and 38-44%, respectively. The precipitation mode involves coprecipitation of multiple heavy metals to form a mineral. These heavy metals are adsorbed on the surface of bacteria through the participation of carboxyl, amino, and phosphate functional groups and extracellular polymeric substances. Therefore, S. marcescens C7-12 has strong biomineralization and adsorption capacity for heavy-metal ions in solution, which can provide potential resources for the bioremediation of heavy-metal-contaminated soil and water.

Multidrug resistance (MDR) in Gram-negative bacteria is a global issue and needs to be addressed urgently. MDR can emerge through genetic mutations and horizontal gene transfer and deteriorate under antibiotic selective pressure. The emergence of resistance to last-resort antibiotics, which are used to treat MDR bacteria, is of particular concern. Colistin has been recognized as a last-line antibiotic for the treatment of MDR Gram-negative bacterial infections caused by Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Recently, the increasing reports of colistin resistance pose a significant threat to public health, caused by both acquired and intrinsic mechanisms. The review aimed to elucidate the trends in colistin resistance, the use of colistin in human and veterinary medicine, underlying resistance mechanisms and transmission pathways, and potential mitigation of this emerging threat through novel intervention strategies. Colistin resistance is mediated by plasmid-encoded phosphoethanolamine transferases (mcr-1 to mcr-10) and chromosomal lipid A remodeling pathways. In Escherichia coli, resistance involves mcr-1-10, acrB efflux mutations, pmrA/pmrB, arnBCADTEF, and mgrB inactivation. Klebsiella pneumoniae exhibits mcr-1, mcr-8, mcr-9, mgrB disruption and phoP/phoQ-pmrAB activation. Acinetobacter baumannii harbors mcr-1-4, while Salmonella enterica and Enterobacter spp. carry mcr variants with arnBCADTEF induction. Therapeutic options include adjunct strategies such as antimicrobial peptides, nanomaterials, therapeutic adjuvants, CRISPR-Cas9-based gene editing, probiotics, vaccines, and immune modulators to restore susceptibility. This review identified that specific and wide actions are required to handle the growing colistin resistance, including genomic surveillance, tracing novel resistance mechanisms, and the application of alternative management strategies. The One Health approach is considered a key strategy to address this growing issue.

In the original publication [...].

Gastrointestinal infections are a major cause of morbidity worldwide. Rotavirus (RVA) is the most frequent cause of severe diarrheal disease in children and is associated with high direct and indirect costs. Symptoms of RVA infection are nonspecific, so diagnostic confirmation requires laboratory testing, which is not routinely performed due to its high cost. For this reason, only a small proportion of hospitalizations are correctly classified. In this context, this study was conducted to determine the prevalence of RVA and 19 other potential etiological agents in 642 samples from pediatric patients with gastrointestinal symptoms at the Social Security Mexican Institute (IMSS). The findings revealed a prevalence of RVA of 26.8%. When analyzing the 321 samples that were processed for the full panel, the positivity rate was 94.4% (for any of the etiological agents tested) and a high percentage of coinfections were detected (69.8%), including up to seven different etiological agents in the same child. The RVA was more frequent in children under 1 year of age, with higher circulation in winter and spring, while bacterial infections showed a seasonal trend in summer. The proportion of hospitalizations was higher in coinfections than in monoinfections, and RVA was the pathogen with the highest percentage of hospitalizations. The results emphasize the etiological complexity of gastrointestinal infections in the pediatric population, highlighting the importance of using multiplex diagnostic tests for appropriate clinical care and effective epidemiological control strategies.