Microorganisms最新文献

Polyester fibers are extensively used in textiles, packaging, and industrial applications due to their durability and excellent mechanical properties. However, high-crystallinity polyester fibers represent a major challenge in plastic waste management due to their resistance to biodegradation. This study evaluated the biodegradation potential of environmental Bacillus isolates, obtained from mold-contaminated black bean plastic bags, toward polyethylene terephthalate (PET) and industrial-grade polyester fibers under mesophilic conditions. Among thirteen isolates, five (Bacillus altitudinis N5, Bacillus subtilis N6, and others) exhibited measurable degradation within 30 days, with mass losses up to 5-6% and corresponding rate constants of 0.04-0.05 day^-1. A combination of complementary characterization techniques, including mass loss analysis, scanning electron microscopy (SEM), gel permeation chromatography (GPC), and gas chromatography/mass spectrometry (GC/MS), together with Fourier-transform infrared spectroscopy (FTIR), thermogravimetric/differential scanning calorimetry (TGA/DSC), and water contact angle (WCA) analysis, was employed to evaluate the biodegradation behavior of polyester fibers. Cross-analysis of mass loss, surface morphology, molecular weight reduction, and degradation products suggests a surface erosion-dominated degradation process, accompanied by ester-bond hydrolysis and preferential degradation of amorphous regions. FTIR, TGA/DSC, and WCA analyses further reflected chemical, thermal, and surface property changes induced by biodegradation rather than directly defining the degradation mechanism. The findings highlight the capacity of mesophilic Bacillus species to partially depolymerize polyester fibers under mild environmental conditions, providing strain resources and mechanistic insight for developing low-energy bioprocesses for polyester fiber waste management.

Bacterial infections remain a major challenge to human health, especially in wound healing, where they can cause prolonged inflammation, delayed recovery, and severe complications. Current research is increasingly focused on developing innovative antimicrobial materials capable of overcoming the limitations of conventional antibiotics, whose effectiveness has declined due to the rise in bacterial resistance. Among the various alternatives, silver nanoparticles have gained particular attention for their broad-spectrum antibacterial properties and have already been successfully applied in the functionalization of commercial wound dressings. The aim of this study was to optimize the functionalization of commercial cotton gauzes based on in situ UV-assisted reduction of silver nanoparticles, reducing methanol usage and identifying the minimal silver nitrate precursor concentration to achieve antimicrobial efficacy while maintaining biocompatibility. Different precursor concentrations were then evaluated through cytocompatibility assays (MTT, Live/Dead, and scratch tests on fibroblasts) and antimicrobial analyses against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus (including an antibiotic-resistant strain), and Candida albicans. The results demonstrated that a 0.5% w/w silver nitrate concentration provided strong antimicrobial and antibiofilm activity without compromising textile properties or cytocompatibility. Furthermore, this optimized process reduced material waste, highlighting its potential for scalable production of antimicrobial wound dressings.

Early life is a critical window for immune system development, during which the gut microbiome shapes innate immunity, antigen presentation, and adaptive immune maturation. Disruptions in microbial colonization-driven by factors such as cesarean delivery, antibiotic exposure, and formula feeding-deplete beneficial early-life taxa (e.g., Bifidobacterium, Bacteroides, and Enterococcus) and impair key microbial functions, including short-chain fatty acid (SCFA) production by these keystone species, alongside regulatory T cell induction. These dysbiosis patterns are associated with an increased risk of pediatric autoimmune diseases, notably type 1 diabetes, inflammatory bowel disease, celiac disease, and juvenile idiopathic arthritis. This review synthesizes current evidence on how the early-life microbiota influences immune maturation, with potential effects on the development of autoimmune diseases later in life. We specifically focus on human observational and intervention studies, where treatments with probiotics, synbiotics, vaginal microbial transfer, or maternal fecal microbiota transplantations have been shown to partially restore a disrupted microbiome. While restoration of the gut microbiome composition and function is the main reported outcome of these studies, to date, no reports have disclosed direct prevention of autoimmune disease development by targeting the early-life gut microbiome. In this regard, a better understanding of the early-life microbiome-immune axis is essential for developing targeted preventive strategies. Future research must prioritize longitudinal evaluation of autoimmune outcomes after microbiome modulation to reduce the burden of chronic immune-mediated diseases.

Recognizing cervical cancer as a major public health concern, Romania was among the first EU countries to introduce human papilloma virus (HPV) vaccination in 2008. Despite multiple strategies implemented over the past 17 years, HPV vaccine coverage remains one of the lowest in the EU, while cervical cancer mortality rates are among the highest. To explore the underlying factors, we conducted a cross-sectional study involving 209 family physicians at the national level. The study assessed their attitudes, practice, knowledge, and training needs related to HPV vaccination. The majority of physicians (90%) reported that they provide HPV vaccination services, and 88.5% considered themselves to have good and very good knowledge about HPV, which they routinely share during consultations with patients. However, respondents noted that both physician and public attitudes toward HPV vaccination are only moderately positive, which limits vaccine uptake and the success of prevention efforts. Parental hesitation was the main barrier, mentioned by 81.8% of respondents. The majority (71.3%) of doctors indicated that they were able to adequately respond to patients' questions, but 81.4% of respondents expressed the view that additional training is needed for healthcare professionals on HPV infection and vaccination. These findings highlight the need for coordinated efforts to increase demand and trust in HPV vaccination. Recommended strategies include targeted professional training, public information campaigns, and the development of strong cross-sector partnerships to support vaccination efforts.

Bile contains many bacteria that can contribute to various diseases. Therefore, identifying bile microbiome differences between benign and malignant conditions is essential. In this study, bile samples were collected aseptically from 141 patients with biliary tract cancer (BTC) or benign biliary diseases (BBDs) who underwent endoscopic retrograde cholangiopancreatography or biliary tract surgery. Quality control PCR was performed to amplify the V3-V4 region of the bacterial 16S rRNA gene. Metagenomic sequencing of bile was successfully performed in 35 of 56 samples collected from patients with BTC and 24 of 85 samples from patients with BBD. The mean alpha diversity values comprised 2.788 ± 2.833 and 2.319 ± 1.355 in the BBD and BTC groups, respectively (p = 0.399). The bacterial species (4.7%) were shared between groups, whereas 12.3% and 83% were indicated to patients with BTC and BBD, respectively. Bacteroides coprocola, Prevotella copri, and Bacteroides plebeius were more frequently identified in the bile of patients with BTC, whereas Bacteroides vulgatus and Bacteroides uniformis were more abundant in the bile of patients with BBD. Distinct patterns of microorganism abundance between the two groups of patients suggest association of bile microbiome with disease status, so its diagnostic potential should be validated in further studies.

Bacillus cereus group strains are prolific producers of diverse bacteriocins with significant application potentials; however, their industrial utilization is often hampered by short production cycles and low yields. Using the leaderless bacteriocin toyoncin as a model, we systematically evaluated the impact of culture medium, temperature, and initial pH on its production. Our findings demonstrate that these factors critically affected yield, with no production under oligotrophic, acidic, or high-temperature conditions. Optimal production was achieved in MH medium (initial pH 8.5, 25 °C), significantly enhancing fermentation duration and yield compared to original conditions (LB medium, 30 °C, pH 7.0). Transcriptional analyses revealed that these improvements were attributable to extended transcription periods and increased transcript levels of the toyoncin gene cluster. Furthermore, we demonstrated that toyoncin disappearance in the supernatant is caused by transcriptional cessation and degradation by membrane-associated proteases. By combining optimized fermentation with protease inhibition, a high and stable toyoncin yield of 53.86 mg/L was achieved, representing a 3.07-fold increase over the initial yield (17.52 mg/L). This study establishes an integrated strategy to enhance bacteriocin production through simultaneous optimization of culture conditions and inhibition of enzymatic degradation, providing important insights for advancing bacteriocin development in the Bacillus cereus group.

Shiga toxin-producing Escherichia coli (STEC) is a zoonotic pathogen of public health concern, requiring a One Health approach to clarify its transmission and distribution. However, its prevalence and genomic characteristics in livestock and companion animals remain underexplored in low-income countries. We investigated prevalence and genomic features of STEC in animals in western Ghana, representing the first genomic report of STEC in Ghana. Fecal samples (97) were collected from goats (n = 33), sheep (n = 33), dogs (n = 30), and a cat (n = 1), with STEC detected in 12.1% of goats and sheep samples. Whole-genome sequencing identified serotypes O38:H26, O43:H2, and O157:H7. stx1c and stx2b genes were detected in O38:H26 and O43:H2, whereas stx2c and key virulence genes (chuA, eae, esp, nle, tir, and toxB) were exclusively found in O157:H7. Phylogenetic analysis revealed that O38:H26 isolates form a cluster closely related to clinical strains from the UK. O43:H2 isolates exhibited diverse stx profiles, linking animal, environmental, and clinical strains from North America and the UK. O157:H7 isolates were genetically similar to European clinical and food-derived strains, suggesting that goats and sheep are important STEC reservoirs in Ghana, offering data for public health risk assessment and effective One Health-based control strategies.

The paper describes a predatory Gram-negative bacterium from the genus Bdellovibrio, which was isolated from water of the Lyubozhikha River. As revealed by electron microscopy, the bacterium is an intracellular predator of Gram-negative microorganisms. Its prey range includes Pseudomonas tolaasii, the phytopathogen responsible for brown spot disease in the cultivated button mushroom (Agaricus bisporus). Based on the results of a 16S rRNA gene sequence analysis, the bacterium was identified as Bdellovibrio bacteriovorus strain LR3. We characterized the predator-prey dynamics between B. bacteriovorus LR3 and P. tolaasii, determining the optimal temperature and pH conditions for this interaction. Our results demonstrate the potential of B. bacteriovorus LR3 as a biocontrol agent against P. tolaasii in mushroom cultivation. The possibility of using B. bacteriovorus LR3 against clinical cases Salmonella and Escherichia infections is also addressed.

For future Mars colonization, crop production will be a challenge due to the chemical composition of the Martian Regolith, which contains perchlorates and heavy metals. This research was conducted to determine if the use of Arbuscular Mycorrhizal Fungi (AMF), Plant Growth-Promoting Bacteria (PGPB), and fertilization have a positive effect on tomato growth in a Martian Regolith Analog. The analog contains 52.54% SiO₂, 1.81% TiO₂, 17.66% Al₂O₃, 9.46% Fe₂O₃, 0.145% MnO, 3.43% MgO, 7.09% CaO, 3.95% Na₂O, 1.96% K₂O, and 0.55% P₂O₅. Two hundred and forty tomato plants were grown for 45 days. One hundred and twenty tomato plants grown over perchlorate-polluted analog (1% m/m) died in less than 2 weeks, while 120 tomato plants grown in a non-polluted analog survived. Forty-eight plants supplemented with Long-Ashton solution increased their shoot length 100% more than the control plants and the plants inoculated with the commercial AMF formulation TM-73^MR and PBB; the latter showed 25% mycorrhizal colonization. There was no significant difference between the growth parameters of inoculated plants and non-inoculated plants. However, there was a significant difference compared to the plants supplemented with Long-Ashton solution. The perchlorate is toxic to tomato plants, and the metal content of the analog was not a limiting factor for tomato growth or AMF colonization.

Vancomycin-resistant Enterococci (VRE) are established nosocomial pathogens; however, vancomycin-dependent Enterococci (VDE) represent a rare and underrecognized phenomenon. These organisms paradoxically require vancomycin for growth due to mutations in cell wall precursor synthesis. Limited awareness and significant diagnostic challenges associated with VDE can lead to delayed recognition and treatment failure. We report a case of vancomycin-dependent Enterococcus faecium isolated from a liver transplant recipient receiving oral vancomycin prophylaxis for recurrent Clostridioides difficile infection. The isolate failed to grow on standard media but exhibited robust growth on vancomycin-supplemented agar, confirmed by vancomycin disc diffusion testing and PCR detection of the vanB gene. Additionally, we reviewed four further VDE cases identified over a two-year period in our tertiary care microbiology laboratory. All patients originated from complex care settings, had significant comorbidities, and had received prolonged glycopeptide therapy. We summarize the clinical features, diagnostic findings, and microbiological challenges encountered across this case series. This series documents the first reported Canadian case of VDE and highlights the critical need for clinical vigilance and diagnostic suspicion in high-risk patients with prior enterococcal colonization and ongoing glycopeptide exposure. Laboratory findings such as failure to grow on blood agar coupled with growth around vancomycin discs should prompt specific evaluation for VDE. Our findings reinforce the necessity for targeted antimicrobial stewardship and infection prevention strategies and underscore the remarkable evolutionary adaptability of Enterococci under sustained antimicrobial pressure.