Microorganisms最新文献

Metabolic disorders, including type 2 diabetes mellitus (T2DM), obesity, and metabolic syndrome, are systemic conditions that profoundly impact the skin microbiota, a dynamic community of bacteria, fungi, viruses, and mites essential for cutaneous health. Dysbiosis caused by metabolic dysfunction contributes to skin barrier disruption, immune dysregulation, and increased susceptibility to inflammatory skin diseases, including psoriasis, atopic dermatitis, and acne. For instance, hyperglycemia in T2DM leads to the formation of advanced glycation end products (AGEs), which bind to the receptor for AGEs (RAGE) on keratinocytes and immune cells, promoting oxidative stress and inflammation while facilitating Staphylococcus aureus colonization in atopic dermatitis. Similarly, obesity-induced dysregulation of sebaceous lipid composition increases saturated fatty acids, favoring pathogenic strains of Cutibacterium acnes, which produce inflammatory metabolites that exacerbate acne. Advances in metabolomics and microbiome sequencing have unveiled critical biomarkers, such as short-chain fatty acids and microbial signatures, predictive of therapeutic outcomes. For example, elevated butyrate levels in psoriasis have been associated with reduced Th17-mediated inflammation, while the presence of specific Lactobacillus strains has shown potential to modulate immune tolerance in atopic dermatitis. Furthermore, machine learning models are increasingly used to integrate multi-omics data, enabling personalized interventions. Emerging therapies, such as probiotics and postbiotics, aim to restore microbial diversity, while phage therapy selectively targets pathogenic bacteria like Staphylococcus aureus without disrupting beneficial flora. Clinical trials have demonstrated significant reductions in inflammatory lesions and improved quality-of-life metrics in patients receiving these microbiota-targeted treatments. This review synthesizes current evidence on the bidirectional interplay between metabolic disorders and skin microbiota, highlighting therapeutic implications and future directions. By addressing systemic metabolic dysfunction and microbiota-mediated pathways, precision strategies are paving the way for improved patient outcomes in dermatologic care.

Although bioremediation is considered the most environmentally friendly and sustainable technique for remediating contaminated soil and water, it is most effective when combined with physicochemical methods, which allow for the preliminary removal of large quantities of pollutants. This allows microorganisms to efficiently eliminate the remaining contaminants. In addition to requiring the necessary genes and degradation pathways for specific substrates, as well as tolerance to adverse environmental conditions, microorganisms may perform below expectations. One typical reason for this is the high toxicity of xenobiotics present in large concentrations, stemming from the vulnerability of bacteria introduced to a contaminated site. This is especially true for planktonic bacteria, whereas bacteria within biofilms or microcolonies have significant advantages over their planktonic counterparts. A physical matrix is essential for the formation, maintenance, and survival of bacterial biofilms. By providing such a matrix for bacterial immobilization, the formation of biofilms can be facilitated and accelerated. Therefore, bioremediation combined with bacterial immobilization offers a comprehensive solution for environmental cleanup by harnessing the specialized metabolic activities of microorganisms while ensuring their retention and efficacy at target sites. In many cases, such bioremediation can also eliminate the need for physicochemical methods that are otherwise required to initially reduce contaminant concentrations. Then, it will be possible to use microorganisms for the remediation of higher concentrations of xenobiotics, significantly reducing costs while maintaining a rapid rate of remediation processes. This review explores the benefits of bacterial immobilization, highlighting materials and processes for developing an optimal immobilization matrix. It focuses on the following four key areas: (i) the types of organic pollutants impacting environmental and human health, (ii) the bacterial strains used in bioremediation processes, (iii) the types and benefits of immobilization, and (iv) the immobilization of bacterial cells on various carriers for targeted pollutant degradation.

Historically, there has been a concern for the detection and enumeration of microorganisms in foods, and numerous methods have been developed to determine their microbiological conditions. The present study aimed to compare the numbers of microbes recovered with three sampling methods: drip, excision, and swabbing in vacuum-packed beef. The sampling methods were evaluated in terms of the viable numbers of Enterobacteriaceae, lactic acid bacteria (LAB), Brochrothrix thermosphacta, Salmonella spp., and yeasts and moulds (Y&M). The numbers of B. thermosphacta, Salmonella spp., Enterobacteriaceae, LAB, and M&Y recovered with the drip method were significantly higher (p < 0.05) than those from the other two methods. Regarding excision and swabbing, the recovery of B. thermosphacta and Enterobacteriaceae was higher (p < 0.05) with the excision method than swabbing, while there were no statistical differences (p > 0.05) between both methods for Salmonella spp., LAB, and Y&M. In conclusion, the drip method can recover up to two logarithms more than the other techniques in vacuum-packed meat; hence, it should be considered when designing and implementing sampling systems for the meat industry.

Many infants consume both human milk and infant formula (mixed-fed); however, few studies have investigated how mixed feeding affects the gut microbiome composition and metabolic profiles compared to exclusive breastfeeding or formula feeding. Herein, how delivery mode and early nutrition affect the microbiome and metabolome of 6-week-old infants in the STRONG Kids2 cohort was investigated. Fecal samples were collected from exclusively breastfed (BF; n = 25), formula-fed (FF; n = 25) or mixed-fed (MF; n = 25) participants. Within each feeding group, infants were either delivered vaginally (VD; n = 13) or by Cesarean section (CS; n = 12). Feeding mode affects the fecal microbiome diversity, composition, and functional potential, as well as metabolomic profiles regardless of delivery mode. Alpha and beta diversity of MF differed from that of BF (p < 0.05) but were comparable to FF infants. Functional analyses have shown 117 potential metabolic pathways differed between BF and FF, 112 between BF and MF, and 8 between MF and FF infants (p < 0.05, q < 0.10). Fecal metabolomic profiles of MF and FF clustered together and separated from BF infants. In total, 543 metabolites differed between BF and FF, 517 between BF and MF, and 3 between MF and FF (p < 0.05, q < 0.10). Delivery mode affected overall microbial composition (p = 0.022) at the genus level and 24 potential functional pathways, with 16 pathways being higher in VD than CS infants (p < 0.05, q < 0.10). Metabolomic analysis identified 47 differential metabolites between CS and VD, with 39 being lower in CS than VD (p < 0.05, q < 0.10). In summary, fecal microbiota composition and function and metabolite profiles of 6-week-old MF infants are closer to FF than BF infants.

The emergence of colistin-resistant Enterobacteriaceae in food products is a growing concern due to the potential transfer of resistance to human pathogens. This study aimed to assess the prevalence of colistin-resistant Enterobacteriaceae in raw and ready-to-eat food samples collected from two regions of Italy (Apulia and Basilicata) and to evaluate their resistance phenotypes and genetic characteristics. A total of 1000 food samples were screened, with a prevalence of 4.4% of colistin-resistant Enterobacteriaceae. The majority of the isolates belonged to Enterobacter spp. (60%), followed by Moellerella wisconsensis, Atlantibacter hermannii, Klebsiella pneumoniae, and Escherichia coli, among others. Genomic sequencing and antimicrobial susceptibility testing revealed high levels of resistance to β-lactams, with most isolates exhibiting multidrug resistance (MDR). Notably, seven isolates harbored mcr genes (mcr-1, mcr-9, and mcr-10). Additionally, in four of them were predicted the IncHI2 plasmids, known to facilitate the spread of colistin resistance. Furthermore, 56 antimicrobial resistance genes were identified, suggesting the genetic mechanisms underlying resistance to several antibiotic classes. Virulence gene analysis showed that E. coli and other isolates carried genes linked to pathogenicity, increasing the potential risk to public health. This study emphasizes the role of food as a potential reservoir for colistin-resistant bacteria and the importance of monitoring the spread of AMR genes in foodborne pathogens.

Lactobacillus is a key genus of probiotics commonly utilized for the treatment of oral infections The primary aim of our research was to investigate the probiotic potential of the newly isolated Levilactobacillus brevis DPL5 strain from human breast milk, focusing on its ability to combat biofilm-forming pathogens such as Staphylococcus aureus. Employing in vitro approaches, we demonstrate L. brevis DPL5's ability to endure at pH 3 with survival rates above 30%, and withstand the osmotic stress often found during industrial processes like fermentation and freeze drying, retaining over 90% viability. The lyophilized cell-free supernatant of L. brevis DPL5 had a significant antagonistic effect against biofilm-producing nasal strains of Staphylococcus aureus, and it completely eradicated biofilms at subinhibitory concentrations of 20 mg·mL^-1. Higher concentrations of 69 mg·mL^-1 were found to have a 99% bactericidal effect, based on the conducted probability analysis, indicating the production of bactericidal bioactive extracellular compounds capable of disrupting the biofilm formation of pathogens like S. aureus. Furthermore, genome-wide sequencing and analysis of L. brevis DPL5 with cutting-edge Nanopore technology has uncovered over 50 genes linked to probiotic activity, supporting its ability to adapt and thrive in the harsh gut environment. The genome also contains multiple biosynthetic gene clusters such as lanthipeptide class IV, Type III polyketide synthase (T3PKS), and ribosomally synthesized, and post-translationally modified peptides (RiPP-like compounds), all of which are associated with antibacterial properties. Our study paves the way for the further exploration of DPL5, setting the stage for innovative, nature-inspired solutions to combat stubborn bacterial infections.

Elucidating the gene regulatory mechanisms underlying the gut-brain axis is critical for uncovering novel gut-brain interaction pathways and developing therapeutic strategies for gut bacteria-associated neurological disorders. Most studies have primarily investigated how gut bacteria modulate host epigenetics and gene expression; their impact on host alternative splicing, particularly in the brain, remains largely unexplored. Here, we investigated the effects of the gut-associated probiotic Lacidofil^® on alternative splicing across 10 regions of the rat brain using published RNA-sequencing data. The Lacidofil^® altogether altered 2941 differential splicing events, predominantly, skipped exon (SE) and mutually exclusive exon (MXE) events. Protein-protein interactions and a KEGG analysis of differentially spliced genes (DSGs) revealed consistent enrichment in the spliceosome and vesicle transport complexes, as well as in pathways related to neurodegenerative diseases, synaptic function and plasticity, and substance addiction across brain regions. Using the PsyGeNET platform, we found that DSGs from the locus coeruleus (LConly), medial preoptic area (mPOA), and ventral dentate gyrus (venDG) were enriched in depression-associated or schizophrenia-associated genes. Notably, we highlight the App gene, where Lacidofil^® precisely regulated the splicing of two exons causally involved in amyloid β protein-based neurodegenerative diseases. Although the splicing factors exhibited both splicing plasticity and expression plasticity in response to Lacidofil^®, the overlap between DSGs and differentially expressed genes (DEGs) in most brain regions was rather low. Our study provides novel mechanistic insight into how gut probiotics might influence brain function through the modulation of RNA splicing.

To assess the clinical usefulness of teicoplanin optimized by means of a therapeutic drug monitoring (TDM)-guided approach for treating secondary bloodstream infections (BSIs) caused by Enterococcus faecium. Hospitalized patients having in the period 1 March 2021-31 October 2024 a documented BSI caused by glycopeptide-susceptible Enterococcus faecium being treated with teicoplanin as definitive targeted therapy optimized by means of a real-time TDM-guided expert clinical pharmacological advice (ECPA) program were retrospectively included. Teicoplanin trough concentrations (C_min) ranging from 20 to 30 mg/L were defined as the desired target of efficacy based on international guidelines. Univariate analysis was performed for assessing variables potentially associated with microbiological failure (defined as persistence at the infection site of the index Enterococcus faecium strain after more than 7 days from starting treatment as documented by follow-up blood cultures). Overall, 67 patients (median age 70 years; male 55.2%) were included. Catheter-related BSIs (50.7%) and intrabdominal/biliary tract (29.9%) infections were the main sources of Enterococcus faecium BSI. The desired target of teicoplanin C_min was attained in 62.7% of patients at the first TDM assessment and significantly increased to 85.1% (p = 0.003) at subsequent TDM-guided ECPA instances during the overall treatment course. Microbiological eradication was obtained in 95% of cases (63/67). In the univariate analysis, failing effective source control was the only variable associated with an increased risk of microbiological failure (75.0% vs. 12.7%; p = 0.01). Targeted TDM-guided teicoplanin therapy, coupled with effective source control of the primary infection site by granting microbiological eradication in the vast majority of cases, may be considered a reasonable strategy for managing glycopeptide-susceptible Enterococcus faecium secondary BSIs.

Klebsiella oxytoca toxigenic strains represent a critical health threat, mainly due to their link to antibiotic-associated hemorrhagic colitis. This serious condition results from the bacteria's ability to produce tilimycin and tilivalline cytotoxins. Our research highlights the pivotal role of OmpR, a key regulator within the EnvZ/OmpR two-component system, in controlling the virulence factors associated with K. oxytoca. Our findings strongly indicate that OmpR is a repressor of the aroX and npsA genes, the first genes of aroX and NRPS operons, respectively, which are indispensable for producing these enterotoxins. Notably, in the absence of OmpR, we observe a significant increase in cytotoxic effects on Caco-2 cells. These observations identify OmpR as a crucial negative transcription regulator for both operons, effectively managing the release of these cytotoxins. This research deepens our understanding of the mechanisms of toxigenic K. oxytoca and opens promising avenues for targeting OmpR for new therapeutic interventions. By focusing on this innovative approach, we can develop more effective solutions to combat this pressing health challenge, ultimately improving patient outcomes against this pathogen.

Polybenzoxazines (PBzs), a class of high-performance thermosetting polymers, have gained significant attention for their exceptional thermal stability, mechanical properties, and chemical resistance, making them ideal for aerospace, electronics, and biomedical applications. Recent advancements emphasize their antimicrobial potential, attributed to unique structural properties and the ability to incorporate bio-active functional groups. This review highlights the synthesis, antimicrobial mechanisms, and applications of PBzs and their bio-based derivatives, focusing on sustainable materials science. PBzs demonstrate antimicrobial efficacy through mechanisms such as hydrophobic surface interactions and reactive functional group formation, preventing microbial adhesion and biofilm development. The incorporation of functional groups like amines, quaternary ammonium salts, and phenolic moieties disrupts microbial processes, enhancing antimicrobial action. Modifications with metal nanoparticles, organic agents, or natural bio-actives further augment these properties. Notable bio-based benzoxazines include derivatives synthesized from renewable resources like curcumin, vanillin, and eugenol, which exhibit substantial antimicrobial activity and environmental friendliness. Hybrid PBzs, combining natural polymers like chitosan or cellulose, have shown improved antimicrobial properties and mechanical performance. For instance, chitosan-PBz composites significantly inhibit microbial growth, while cellulose blends enhance film-forming capabilities and thermal stability. PBz nanocomposites, incorporating materials like silver nanoparticles, present advanced applications in biomedical and marine industries. Examples include zirconia-reinforced composites for dental restoration and urushiol-based PBzs for eco-friendly antifouling solutions. The ability to customize PBz properties through molecular design, combined with their inherent advantages such as flame retardancy, low water absorption, and excellent mechanical strength, positions them as versatile materials for diverse industrial and medical applications. This comprehensive review underscores the transformative potential of PBzs in addressing global challenges in antimicrobial material science, offering sustainable and multifunctional solutions for advanced applications.