Search Results (1,885)

Anthracnose caused by Colletotrichum graminicola (Ces.) G.W.Wils is a significant disease of maize (Zea mays) worldwide. To obtain an efficient biocontrol strain and elucidate its mechanisms, 103 bacterial isolates were obtained from soil samples collected in the Tianshan Mountains, Xinjiang, China. Among these, Bacillus atrophaeus F4’s fermentation broth had the highest efficacy in controlling maize anthracnose, reaching 79.78%. To further investigate biocontrol mechanisms of F4 strain, its complete genome was sequenced, assembled, and annotated. Lipopeptides extracted from the fermentation broth of F4 were found to strongly inhibit the growth of hyphae and the germination of conidia in the pathogen. Microscopic and biochemical analyses indicated that the lipopeptide extract inhibited chitin synthesis and disrupted the integrity of the cell wall and membrane, thereby exerting antifungal effects. Further MALDI-TOF MS analysis identified antimicrobial compounds, including surfactin, iturin, and fengycin B, in the lipopeptide extract. Furthermore, plate antagonistic test showed that F4 strain exhibited broad-spectrum antagonistic activity against multiple plant pathogenic fungi. F4 strain also displayed motility, biofilm-forming capacity, and the ability to produce extracellular enzymes such as proteases and amylases, which are associated with biocontrol activity. These findings suggest the significant potential of B. atrophaeus F4 as a biocontrol agent against maize anthracnose. Full article

The development of dental restorative materials with improved physical and mechanical properties is an important area of research. In this study, hexaallylaminocyclotriphosphazene (HAP) was used to modify dental composites. HAP is a compound with multiple carbon-carbon bonds that can react with methacrylic resins to form a copolymer. HAP was synthesized by reacting allylamine with hexachlorocyclotriphosphazene and characterized it using ¹H and ³¹P NMR spectroscopy and MALDI-TOF mass spectrometry. Molecular dynamics simulations using the MM2 force field showed that HAP has a nanosize (the diameter of a sphere eclosing the molecule is 1.3 nm), making it a suitable nanomodifier for dental composites. Using 3D printing, samples of dental methacrylic composites containing up to 10 wt. % HAP were prepared and their physicomechanical properties and antibacterial activity against gram-positive bacteria S. mutans were studied. As a result, it was established that the maximum flexural strength (115.1 ± 10.2 MPa) is achieved with a modifier content of 5 wt.% in the composite. The maximum value of inhibition of S. mutans growth in a liquid nutrient medium is achieved with a HAP content of 10 wt.% in the sample. Furthermore, with a HAP content of more than 5 wt.% in the composite, inhibition of biofilm on the material surface is observed. The resulting composite is proposed for use as dental crowns in restorative dentistry. Full article

In our previous work, we reported for the first time the presence of enterocin-encoding genes in novel Lacticaseibacillus paracasei (L. paracasei) and Levilactobacillus brevis (Lev. brevis) strains isolated from artisanal dairy products made from raw cow milk. The aim of this study was to isolate enterocin-positive lactic acid bacteria (LAB) from artisanal dairy products and assess their technological characteristics and safety for potential application in food systems. LAB isolates were characterized using phenotypic tests, Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) identification, and PCR detection of enterocin genes, followed by evaluation of their physiological and technological properties and a comprehensive safety assessment, including antimicrobial resistance, virulence, biogenic amine, and integron genes. Two strains, L. paracasei S2 and Lev. brevis S62, carried enterocin genes (entAS-48 and entQ) and exhibited strong acidifying and proteolytic activities, along with antibacterial effects against foodborne pathogens and reference strains. Both isolates tolerated environmental stresses, including low pH, and lacked virulence factors, clinically relevant antibiotic resistance genes, biogenic amine production, and integron elements. These results indicate that the strains are safe, multifunctional, and suitable for developing regionally adapted dairy products, highlighting artisanal dairy products as a valuable source of novel LAB with promising biotechnological applications. Full article

In the context of evolving antifungal resistance and increasing reports of clinical outbreaks of non-albicans Candida spp. invasive infections, the rapid detection of resistant patterns is of the utmost importance. Currently, an azole-resistant Candida parapsilosis clinical outbreak is ongoing at Pisa University Hospital. Resistant isolates bear both Y132F and S862C amino acid substitutions. Based on the data and isolates retrieved during the clinical outbreak, mass spectrometry was used to investigate the differences between fluconazole-resistant and -susceptible clinical strains directly from yeast colonies isolated from agar culture media. A total of 39 isolates, 16 susceptible and 23 resistant, were included. Spectra were processed following a standardized pipeline. Several supervised machine learning classifiers such as Random Forest, Light Gradient Boosting Machine, and Support Vector Machine, with and without principal component analysis were implemented to discriminate resistant from susceptible isolates. Support Vector Machine with principal component analysis showed the highest sensitivity in detecting fluconazole resistance (100%). Despite these promising results, external prospective validation of the algorithm with a higher number of clinical isolates retrieved from multiple clinical centers is required. Full article

Co-infections are increasingly recognized as drivers of disease in ornamental fish, yet their genomic underpinnings and zoonotic implications remain underexplored compared to farmed species. Leveraging a One Health perspective, we investigated an acute mortality event in koi carp and characterized a co-infection by opportunistic aquatic bacteria that are also implicated in human disease. We isolated Aeromonas veronii and Shewanella sp. from a moribund koi using culture, biochemical assays, and MALDI-TOF MS, then generated draft genomes and performed orthology (OrthoVenn3), pathway annotation (KEGG BlastKOALA/Mapper), secondary-metabolite mining (antiSMASH), and virulence/resistome screening (VFDB/CARD), complemented by antimicrobial susceptibility testing. Clinically, affected fish showed dropsy/ascites, scale loss, abnormal buoyancy, and reduced activity. Phylogenomics positioned A. veronii Koi-2 within the A. veronii complex near species thresholds (ANI ~96.1%; dDDH ~70.2%), while Shewanella sp. Koi-1 formed a distinct lineage below accepted cut-offs relative to S. seohaensis (ANI ~95.9%; dDDH ~67.6%). The virulome comprised 194 loci in A. veronii Koi-2 and 152 in Shewanella sp. Koi-1 is enriched for adhesion, secretion, iron uptake, and immune-evasion functions. Genotype–phenotype agreement was high for multidrug resistance: Shewanella sp. encoded OXA-436 and rsmA, matching β-lactam resistance and reduced fluoroquinolone/phenicol susceptibility, whereas A. veronii carried tet(A), OXA-1157, cphA3, sul1, and aadA3 consistent with tetracycline, β-lactam, sulfonamide, and aminoglycoside resistance profiles. In conclusion, genome-resolved diagnostics confirmed a mixed Aeromonas–Shewanella co-infection with broad virulence potential and convergent resistance mechanisms, supporting the routine use of genomics to distinguish single- versus mixed-agent disease and to guide dual-coverage, mechanism-aware therapy in ornamental fish medicine while informing zoonotic risk mitigation. Full article

Intense training loads alter the skin microbiome and defence mechanisms in athletes, yet adaptation profiles remain insufficiently characterised. This study evaluated the relationships between skin bacterial microbiome structure, antimicrobial activity, dermcidin levels, and acne severity in male professional hockey players compared with amateur athletes and non-athletes. One hundred men (18–57 years) were examined and allocated to six subgroups by exercise intensity and acne status. Microbiota composition was assessed by culture-based methods and MALDI-TOF identification, antimicrobial activity measured spectrophotometrically, dermcidin quantified by ELISA, and sweat proteome characterised by HPLC-MS. Staphylococcus epidermidis and Micrococcus luteus predominated in all groups. Exercise intensity, rather than acne, was the main determinant of total bacterial colonisation, which increased approximately tenfold from non-athletes to professional hockey players. In non-athletes, higher antimicrobial activity correlated with greater acne severity, whereas in professionals this relationship was absent and dermcidin levels showed an inverse association with acne severity. Proteomic analysis identified 17 polypeptides; dermcidin and prolactin-inducible protein were dominant in all groups, and calprotectin (S100-A8/A9) was detected exclusively in healthy professionals. Full article

Background: Nosocomial infections represent a significant clinical burden due to high morbidity, mortality and healthcare costs. Invasive fungal infections, particularly those caused by Candida species, are of growing concern due to increasing antifungal resistance, which limits therapeutic options and worsens patient outcomes. This study aimed to characterize the prevalence, species distribution, antifungal susceptibility profiles, and molecular mechanisms of resistance in clinical Candida isolates from hospitalized patients. Methods: A cross-sectional study was conducted involving 55 hospitalized patients, yielding 60 isolates from blood, secretions, fluids, and catheter tips. Species identification was performed using chromogenic media and confirmed by MALDI-TOF MS. Antifungal susceptibility testing followed CLSI M27-A4 broth microdilution guidelines for amphotericin B, fluconazole and 5-flucytosine. Gene expression of ERG2, ERG11 and MDR1 was evaluated by RT-qPCR after exposure to subinhibitory antifungal concentrations using the 2^−∆∆Ct method. Results:Candida albicans was the most frequent species, followed by Nakaseomyces glabratus, C. tropicalis and C. parapsilosis. Resistance varied among species, with elevated rates for fluconazole. ERG2 was notably overexpressed in amphotericin B-resistant isolates, while ERG11 and MDR1 showed species-dependent variation. Conclusions: Resistance mechanisms in Candida are species-specific and drug-dependent. Accurate species identification and understanding their molecular profiles are essential to guide targeted antifungal therapy and improve clinical outcomes. Full article

Objective: Airway hyperresponsiveness (AHR) is a hallmark feature of asthma; however, its precise molecular mechanisms remain incompletely defined. In this study, we investigated protein expression in airway smooth muscle that may contribute to AHR, using an experimental model of ovalbumin-induced allergic asthma. Methods: Guinea pigs were sensitized and challenged with ovalbumin. Airway responsiveness to histamine was assessed, and proteomic analysis of the tracheal tissue was conducted using electrophoresis followed by MALDI/TOF-TOF mass spectrometry. Specific protein bands corresponding to the myosin phosphatase target subunit 1 (MYPT1) were analyzed, and regulatory subunit of glycogen-targeted phosphatase 1 (RG1) was further evaluated through immunohistochemistry. Results: MYPT1, previously associated with AHR, was not detected in the proteomic analysis. Interestingly, an RG1 peptide was identified. Immunohistochemistry showed a differential expression pattern was observed for the RG1 and Rho-associated protein kinase 2 (ROCK2), both of which were significantly upregulated in airway smooth muscle and positively correlated with the degree of AHR. Moreover, a significant positive correlation was observed between RG1 and ROCK2 expression levels. MYPT1 and its phosphorylated forms (Thr⁶⁹⁶ and Thr⁸⁵⁰), along with ROCK1 immunostaining, did not differ from controls. Conclusions: These findings suggest that RG1, along with ROCK2, may play an important role in airway hyperresponsiveness characteristic of asthma. Full article

Background/Objectives: Antibiotic-resistant strains have been reported in aquatic ecosystems, with varying prevalence and resistance patterns by region. In Tamaulipas, Mexico, little information has been generated on this topic, making it difficult to estimate their potential risk to environmental and human health. Therefore, the objective of this study was to evaluate the presence and virulence of antibiotic-resistant strains of Pseudomonas aeruginosa in environmental water from Tamaulipas, Mexico. Methods: One hundred water samples were collected from different water bodies in Tamaulipas to identify P. aeruginosa by PCR and MALDI-TOF, virulence gene detection, antimicrobial susceptibility testing, and detection class 1 integrons. Results: In this study, 109 P. aeruginosa strains were isolated. Eight virulence genes were identified in 47.7% to 80.7% of the strains, with the rhlAB gene being the most frequent. The strains showed resistance or intermedia resistance to 10 of the 16 antibiotics tested, in a range of resistance values 0.9–66.2%. In total, 100% (109/109) were susceptible to ceftazidime (CAZ), gentamicin (GM), amikacin (AN), netilmicin (NET), tobramycin (NN) and norfloxacin (NOR), and 65.7% were resistant to ticarcillin/clavulanic acid and 53.5% to ticarcillin; the resistance to the remaining antibiotics was between 19.4% and 0.9%. The class 1 integron was not identified in any of the strains analyzed. Conclusions:P. aeruginosa in environmental waters of Tamaulipas showed potential to cause infections and low rates of resistance to most of the antibiotics tested. However, 20% were resistant to one of the most common treatments, which could pose a risk to public health. Full article

The One Health approach emphasizes the importance of zoonoses due to their pandemic potential, highlighting the need to characterize emerging bacterial pathogens across animal reservoirs. Non-typhoidal Salmonella (NTS) species are among the most common zoonotic agents and can be transmitted by various reservoirs, including reptiles. Both direct and indirect contact with reptiles may result in Reptile-Associated Salmonellosis (RAS), which mainly affects children, immunocompromised individuals, pregnant women, and the elderly. This study aimed to isolate and characterize the Gram-negative intestinal microbiota from free-living snakes in Poland (Natrix natrix, Natrix tessellata, Coronella austriaca, Zamenis longissimus, and Elaphe dione) and to determine the prevalence and virulence potential of Salmonella. Using MALDI-TOF Mass Spectrometry, 432 isolates were identified. Serological analysis of 62 Salmonella isolates revealed 10 distinct O-antigen groups, and rare serovars O:38, O:48, O:57 and others were confirmed. Salmonella isolates were tested for antibiotic susceptibility and resistance to Human Serum; most isolates survived exposure to serum while remaining susceptible to antibiotics. One isolate was classified as multidrug-resistant (MDR), showing resistance to amoxicillin/clavulanic acid, ampicillin, cefuroxime, cephalexin, tigecycline, and fosfomycin. These findings demonstrate that wild snakes in Poland can act as reservoirs of pathogenic and zoonotic Salmonella, emphasizing their epidemiological significance in natural ecosystems. Full article

Carbapenem-resistant Klebsiella pneumoniae isolates harbouring double carbapenemases, from patients in a surgical and transplantation ICU, were investigated to better understand the dispersion of the pathogen. Twenty-three carbapenem-resistant K. pneumoniae isolates harbouring at least two different carbapenemases (by immunochromatography screening), were consecutively collected during a seven-month period from patients in a surgical and transplantation ICU. Identification and susceptibility testing were performed using the MALDI-TOF Vitek MS and the Vitek2 system (BioMerieux), respectively. Whole genome sequencing (WGS) was performed in an Illumina NextSeq2000 platform and MLST and resistome analysis of assembled genomes were performed by ResFinder, through the Center for Genomic Epidemiology platform. All isolates were resistant to ertapenem, imipenem, meropenem, and most to meropenem–varbobactam. Seventeen isolates belonged to the ST11 type and were positive for the OXA-48/NDM combination (by immunochromatography and NGS). Four isolates belonged to the ST39 type and were positive for the KPC/NDM combination (by immunochromatography and NGS). Finally, two isolates belonged to the ST258 type. One of them was positive for the OXA-48/KPC/NDM combination (by immunochromatography), but only bla_KPC was detected by WGS, and the second was positive for the OXA-48/KPC combination (by immunochromatography) and confirmed by WGS. This is the first report of an outbreak in Greece due to two simultaneous carbapenem-resistant populations harbouring double carbapenemases: a larger one comprising ST11 isolates harbouring the combination bla_NDM-1/bla_OXA-48, coupled by a smaller one comprising ST39 isolates harbouring the combination bla_KPC-2/bla_NDM-1. The implications of this particular situation regarding public health as well as intra-nosocomial infection prevention and control should be further monitored and studied. Full article

Background/Objectives: The growing demand for functional foods and alternative therapeutic strategies has intensified the search for novel probiotic strains from underexplored ecosystems. This study aimed to isolate and phenotypically characterize lactic acid bacteria (LAB) from spontaneously fermented fruits found in the Legal Amazon (Ananas comosus, Humiria balsamifera, Manilkara zapota, and Platonia insignis) and to perform genome-based analysis of the most promising isolate to evaluate its probiotic potential. Methods: The isolates were identified by MALDI-TOF-MS and screened for tolerance to low pH, bile salts, lysozyme, growth at 39 °C, and antimicrobial activity against five enteric pathogens. The most promising isolate was evaluated by coaggregation and biofilm assays, in silico proteome and CAZyme analysis, bacteriocin cluster mining, and in vivo efficacy testing using Tenebrio molitor larvae. Results: Three isolates from H. balsamifera were identified as Lactiplantibacillus plantarum (M1, M2, M4) by MALDI-TOF-MS. These isolates exhibited high resilience to all tested physiological stressors. Antimicrobial activity was contact-dependent, with no inhibition by cell-free supernatants. M2 showed the strongest pathogen exclusion, moderate biofilm formation, and high coaggregation with S. enterica and E. faecalis. Genome analysis of M2 revealed a 3.40 Mb chromosome, absence of acquired resistance or virulence genes, two plantaricin gene clusters, and 93 CAZymes, including GT families linked to exopolysaccharides biosynthesis. SignalP predicted secretion signals in 10 CAZymes. M2 significantly improved larval survival against E. coli and S. enterica, especially under prophylactic treatment. Conclusions: L. plantarum M2 combines safety, stress tolerance, genomic features, and in vivo efficacy, positioning it as a promising probiotic candidate adapted to tropical niches. These findings highlight H. balsamifera as a reservoir of novel probiotic strains. Full article

In this study, the structural changes and reconstruction mechanism of sesame protein-derived amyloid fibrils under varied digestive parameters (pepsin concentration, digestive pH and ionic strength) during gastric digestion were investigated, and the effect of fibril reconstruction on the gastric digestion stability of β-carotene nanoparticles was also explored. The results demonstrated that amyloid fibrils underwent a three-stage dynamic process of enzymatic hydrolysis, regeneration and degradation during gastric digestion. The pepsin concentration of 2 mg/mL was found to promote the balance between fibril hydrolysis and regeneration. The fibrils displayed a pronounced regenerative capacity at pH values of 1.5 and 2.5, whereas at pH 3.5, which was proximal to the isoelectric point of protein, aggregation and precipitation were observed. Furthermore, it was found that 10 mM NaCl exerted minimal influence on fibril stability, whereas the higher concentrations of salt ions were shown to obstruct regeneration and promote aggregation. Analyses through SDS-PAGE, GPC, and MALDI-TOF-MS revealed a gradual reduction in the molecular weight of the fibrils during gastric digestion, with certain fragments reaggregating to form new fibril structures. The fibril-based delivery system formed a stable protective structure for β-carotene nanoparticles, which not only prevented their aggregation but also facilitated their release in the small intestine. Full article

Backgrounds/Objectives: This study aimed to quantify biofilm production and characterize the distribution of the biofilm-associated ica genes (icaA, icaD, icaB, icaC, icaR) in coagulase-negative staphylococci (CoNS) isolates, and to assess the association between these genes and antibiotic resistance profiles. Methods: A total of 121 CoNS isolates collected at Ümraniye Training and Research Hospital between 1 January and 30 August 2024 were identified by VITEK 2 Compact and MALDI-TOF MS. Biofilm production was quantified using the microtiter plate assay, and the presence of ica genes was determined by quantitative real-time PCR (qPCR). Antimicrobial susceptibility testing (AST) was performed with the VITEK 2 Compact (bioMérieux), and minimum inhibitory concentrations (MICs) were interpreted according to EUCAST criteria. Results:S. epidermidis was found to have the highest biofilm production capacity among the CoNS isolates, followed by S. haemolyticus. The icaA gene was detected in 99.17% of isolates, followed by icaR (70.24%), icaD (55.37%), and both icaB and icaC (28.92% each). The highest resistance rates were observed for oxacillin (85.8%) and erythromycin (85.1%), while all isolates remained susceptible to linezolid, daptomycin, and vancomycin. Conclusions: The high prevalence of ica genes in CoNS isolates indicates that biofilm formation plays a critical role in the pathogenesis of these species. The findings reveal that CoNS have a strong biofilm production potential, which is a decisive factor in their pathogenicity. However, the high methicillin resistance rates emerge as one of the main factors limiting the effectiveness of current treatment options. Therefore, future studies need to focus on the development of anti-biofilm approaches and alternative therapeutic strategies. Full article

Socol is an artisanal meat product typical of Southeast Brazil. It is made from pork loin and ripened at room temperature. This work aimed to isolate, quantify, and identify lactic acid bacteria (LAB) in Brazilian dry-cured loin (Socol) as well as evaluate their in vitro probiotic potential. LAB were found in high amounts, varying from 2.5 × 10³ to 9.2 × 10⁶ CFU g⁻¹. Eleven isolated bacteria were identified by Matrix-Assisted Laser Desorption Ionization–Time-Of-Flight/Mass Spectrometry (MALDI-TOF/MS). Of these, six strains (Latilactobacillus brevis SFC1A, Latilactobacillus sakei SFC2A, Latilactobacillus curvatus SFC6A, Pediococcus acidilactici SFC9A, Latilactobacillus curvatus SFC11A, and Pediococcus pentosaceus SFC11B) were submitted to in vitro probiotic tests. All were tolerant to bile salts and five of them to artificial gastric juice, and were all sensitive to tetracycline, chloramphenicol, and erythromycin. L. brevis SFC1A and P. acidilactici SFC9A inhibited all tested pathogenic bacteria and showed the broadest in vitro probiotic activity. Thus, they would be recommended as starter cultures for the elaboration of novel fermented meat products and to compose a bank of indigenous bacteria, as well as contribute to preserving Socol microbiota. Full article