Search Results (392)

Background: Nosocomial infections caused by multidrug-resistant microorganisms are a significant public health concern. Antimicrobial resistance (AMR) is closely linked to the excessive and indiscriminate use of antibiotics, which creates selective pressure and promotes the emergence of resistant pathogens. Objectives: This study evaluates the synergistic potential of intragenic antimicrobial peptides (IAPs) combined with plant alkaloids against susceptible and multidrug-resistant human pathogenic bacteria, assessing antimicrobial activity, biofilm inhibition, and hemocompatibility. Methods: The tested molecules included berberine, tomatidine, sinomenine, and the IAPs Hs02 and Gr01. Minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) assays were performed against both ATCC (E. coli ATCC 25922 and S. aureus ATCC 25923) and clinical strains (E. coli KPC+ HRAN 1812446 and S. aureus MDR LACEN 3730529). Synergistic interactions were evaluated by checkerboard assay, followed by biofilm inhibition and hemolysis assays using human red blood cells. Results: Berberine exhibited a MIC of 1024 µM when tested individually, while tomatidine and sinomenine showed no significant activity. As expected, the IAPs showed strong antimicrobial properties at 8 µM (Hs02) and 4 µM (Gr01). When tested in synergy, alkaloids and IAPs reduced the MIC by up to 128-fold. The combination of IAPs and alkaloids reduced the biofilm biomass of S. aureus and E. coli by 50%, by the crystal violet assay (p < 0.05). Notably, sinomenine had not previously been reported to have antimicrobial activity. Conclusions: These results highlight the importance of further exploring combinations of natural and synthetic bioactive molecules as promising antimicrobial candidates. This approach may help to extend the useful life of conventional antibiotics. However, further studies are needed to assess safety, cytotoxicity, genotoxicity, inflammation, and in vivo effects. Full article

Probiotics are known to benefit human health through improving the gut environment. This study aimed to investigate whether Streptococcus salivarius (S. salivarius) G7 exhibits probiotic properties and evaluated its effectiveness and suitability for oral health applications. Whole-genome sequencing of S. salivarius was performed using Novo assembly and bioinformatics analysis. To determine probiotic suitability, the required metabolic profiles were obtained through performing a hemolysis test, antibiotic susceptibility test, D-lactate production assay, and cytotoxicity assay according to the methods recommended in World Health Organization guidelines. To investigate the oral health impacts of S. salivarius, the acidogenicity and antimicrobial activity of S. salivarius were investigated. Finally, oral biofilms treated and untreated with S. salivarius were investigated. The phylogenetic and bioinformatic analyses confirmed the taxonomic identity of S. salivarius. Also, it has been proven that this bacterium carries no virulence factors or transmissible antibiotic resistance genes. S. salivarius G7 exhibited low antibiotic resistance, cytotoxicity, and acidogenicity, while also displaying antimicrobial activity against oral disease-related bacteria, and was able to maintain eubiosis in oral biofilms. S. salivarius G7 met all the safety assessment criteria required by current probiotic guidelines and exhibited beneficial properties for oral health. Therefore, this strain may represent a safe and promising probiotic candidate for oral health applications. Full article

Background/Objectives: Achillea millefolium is a well-known medicinal plant recognized in several pharmacopeias, while the Balkan endemic species Achillea clypeolata lacks a pharmacopeial monograph and remains insufficiently studied despite its traditional use. This study aimed to comparatively evaluate the phytochemical composition and biological potential of both species. Methods: Chemical composition was studied using UHPLC-MS/MS, HPLC, and FT-IR; anti-inflammatory potential was analyzed by erythrocyte membrane stabilization assay (heat- and hypotonicity-induced hemolysis); and enzyme-inhibitory activity was tested against collagenase, elastase, hyaluronidase, and tyrosinase. In addition, antioxidant activity was evaluated using DPPH, ABTS, and DCFDA assays; antimicrobial activity was determined using the broth microdilution method; and cytotoxic potential was investigated by the MTT assay. Results: The major constituents in water–ethanolic extracts were quinic acid derivatives, flavonoids, phenolic acids, and coumarins, with chlorogenic acid, 3,5-dicaffeoylquinic acid, cosmosiin, cynaroside, rutin, and hyperoside as dominant in both species. Extracts exhibited marked anti-inflammatory activity, where A. millefolium provided greater protection under heat-induced hemolysis, and both extracts showed comparable efficacy under osmotic stress. Concentration-dependent inhibition of collagenase, elastase, hyaluronidase, and tyrosinase (concentration from 62.5 to 1000 µg/mL), along with significant antioxidant activity in ABTS and DPPH assays, was observed. In MRC-5 cells, the extracts reduced AAPH-induced ROS levels up to 50 µg/mL, while higher concentrations showed diminished effects. Moderate cytotoxicity was observed, with A. clypeolata displaying stronger effects at 50–100 µg/mL. Both Achillea species exhibited broad-spectrum antimicrobial activity, with pronounced effects against Gram-positive bacteria. Conclusions: The results support the traditional use of Achillea species and highlight A. clypeolata as a promising, yet underexplored, source of bioactive compounds for dermatological and pharmaceutical applications. Full article

According to the complementary advantages of the composites, the degradation rate, biological activity and physical and chemical properties of the composites were adjusted by using the hydrophilic and bioactive advantages of soy protein isolate (SPI) on the basis of toughening PLA by polycaprolactone (PCL). In this study, soy protein isolate/polylactic acid–polycaprolactone (SPI/PLA–PCL) composite microspheres were fabricated via double emulsion–solvent evaporation. SPI was introduced to regulate hydrophilicity, biodegradation, and bioactivity based on PCL–toughened PLA. The microspheres were characterized by SEM, EDS, FTIR, and XRD. Hydrophilicity, thermal stability, and degradation behavior were evaluated via water contact angle, TG/DTA, and in vitro degradation assays. Biocompatibility, hemocompatibility, and osteogenic activity were assessed through cell adhesion, hemolysis, CCK–8, ALP, alizarin red staining, and mineralization tests. Results confirmed the successful preparation of SPI/PLA–PCL microspheres. SPI incorporation enhanced hydrophilicity, degradation rate, and cell adhesion. The composite microspheres exhibited favorable thermal stability, hemocompatibility, biocompatibility, and osteogenic induction. The 50% SPI/PLA–PCL group performed optimally in cell proliferation, adhesion, ALP activity, and mineralization, demonstrating promising potential for bone tissue engineering applications. Full article

Urolithiasis is a condition characterized by the crystallization of urinary solutes and their accumulation as solid aggregates in the urinary tract. Effective pharmacological strategies for preventing crystal formation and oxidative stress-related urinary disorders remain limited. Mimosa malacophylla is traditionally used in northeastern Mexico for kidney disorders; however, its biological activities have not been fully characterized. In this study, a methanolic extract of M. malacophylla was obtained by maceration and evaluated for its phytochemical profile and biological activities. Preliminary phytochemical screening, total phenolic content, and high-performance liquid chromatography coupled to mass spectrometry (HPLC-MS) were used to characterize the extract. Antiurolithic activity was assessed by a calcium oxalate nucleation assay, while antioxidant, antimicrobial, hemolytic, and brine shrimp lethality assays were also performed. The extract showed a yield of 6.25% (w/w) and a total phenolic content of 6.41 mg GAE/g of extract. HPLC-MS analysis revealed a profile rich in flavonoid glycosides and phenolic derivatives, including rutin, luteolin, and apigenin. The extract exhibited under in vitro conditions a high inhibitory effect on calcium oxalate nucleation (95.47%) and notable antioxidant capacity, while no antibacterial activity was detected. Hemolysis was below 1% and the LD₅₀ in Artemia salina was 1174.23 ± 17.94 μg/mL. These findings suggest that M. malacophylla may be a source of bioactive compounds with potential relevance in early stages of crystal formation for the management of urolithiasis. Full article

Intestinal dysfunction and parenteral nutrition (PN) can trigger a spectrum of liver disorders collectively referred to as intestinal failure-associated liver disease (IFALD), for which therapeutic options remain limited. In the present study, we investigated the modulatory effects of the bioactive xanthophyll carotenoid lutein in an in vitro IFALD model utilizing human THLE-2 hepatocytes exposed to lipopolysaccharide and Intralipid to mimic PN–associated inflammatory and metabolic stress. Because lutein is poorly water-soluble and patients receiving PN lack enteral intake of this compound, we also evaluated the cyto- and hemocompatibility of a human serum albumin–based lutein nanoformulation developed to enable intravenous administration. A bead-based multiplex immunoassay revealed that lutein attenuated dysregulation of inflammatory and metabolic signaling by modulating total and phosphorylated levels of MAPKs, NF-κB, Akt, STAT5, CREB, and p70S6K. Lutein also affected lipid metabolism–related gene expression, decreasing SREBF2 and restoring ABCA1 and PRKAA2 mRNA toward control levels, as determined by qPCR. Nanoformulated lutein, with a mean particle size of approximately 160 nm, was non-toxic in THLE-2 cells and exhibited hemocompatibility in a human erythrocyte hemolysis assay. Together, our findings provide both biological and technological rationale for further exploration of lutein-based strategies to mitigate IFALD in patients receiving PN. Full article

Background: Dental caries remains one of the most prevalent oral diseases worldwide, largely driven by the virulence of Streptococcus mutans. Although plant phenolics from green tea and pomegranate are known for their antimicrobial properties, their molecular mechanisms of action against key S. mutans virulence targets remain insufficiently characterized. Aim: This study investigated the antibacterial and anti-virulence properties of Viroelixir, a phenolic-rich formulation derived from green tea (Camellia sinensis) and pomegranate (Punica granatum), against S. mutans, with particular emphasis on predictive molecular docking interactions with critical virulence-associated proteins. Methods: Viroelixir phytochemical composition was characterized by LC–MS using a C18 reverse-phase column and negative electrospray ionization mode. Antibacterial activity was evaluated using growth kinetics, agar plating, and crystal violet assays. Acidogenicity, hemolytic activity, and biofilm formation were assessed using pH modulation, hemolysis assays, SEM, and biofilm biomass quantification. Virulence gene expression was analyzed by RT-qPCR. In silico molecular docking was performed to explore potential interactions between major LC–MS-supported phenolic constituents and S. mutans virulence proteins, including glucosyltransferase B (GtfB), LuxS, and SpaP. Biocompatibility was evaluated in human gingival epithelial cells. Results: The LC-MS analysis revealed a complex mixture of phenolic compounds consistent with catechins and ellagitannins. Compound identification was considered tentative and based on mass spectral range and chromatographic behavior. Viroelixir significantly inhibited S. mutans growth, acid production, hemolytic activity, and biofilm formation in a concentration-dependent manner. Key virulence genes were markedly downregulated. Docking analyses suggested stable binding of selected phenolics—particularly punicalagin, catechin, and epigallocatechin—within the active sites of GtfB, LuxS, and SpaP. Importantly, Viroelixir showed no cytotoxic effects on gingival epithelial cells. Conclusions: Viroelixir exerts potent antibacterial and anti-virulence effects against S. mutans through a multi-target mechanism combining transcriptional suppression and predictive molecular inhibition of virulence proteins, supporting its potential as a safe, natural therapeutic for caries prevention. Full article

Gadolinium-based contrast agents are widely used in clinical magnetic resonance imaging (MRI) due to their strong paramagnetic properties and ability to enhance image contrast. Despite their diagnostic value, concerns remain regarding gadolinium toxicity and long-term tissue retention, particularly for less stable linear chelates. In this study, we report preliminary results on a newly synthesized gadolinium-based compound (L-Gd), in which the Gd³⁺ ion is coordinated to a specific ligand designed to improve biocompatibility. To evaluate the feasibility of L-Gd encapsulation within human RBCs (hRBCs) for drug delivery, its biocompatibility and cellular interactions were thoroughly investigated. RBCs represent an attractive biomimetic carrier system capable of limiting the direct exposure of tissues to paramagnetic agents while potentially improving circulation time and safety. In vitro assays demonstrated that L-Gd maintains high compatibility with hRBCs within specific concentration ranges, showing no significant hemolysis or morphological alterations. Furthermore, preliminary encapsulation studies indicate that L-Gd can be successfully associated with RBCs, supporting the potential of this approach for contrast agent delivery. These findings suggest that RBC-mediated transport of gadolinium complexes may represent a promising strategy to reduce toxicity and mitigate gadolinium retention. Further investigations will focus on optimizing encapsulation efficiency, relaxometric properties, and in vivo behavior of the L-Gd system. Full article

To date, the problem of mastitis in cattle remains relevant for both the industrial sector and scientific research. Despite numerous active investigations, the causes of this disease have not been fully established. It is postulated that several factors may be involved, such as bacterial pathogens, animal husbandry practices, and weather and climatic conditions. In this study, we selected cows from farms in Yakutia to investigate microbial isolates present in the milk of cows affected by mastitis and treated with antibiotics. Five identified Staphylococcus aureus isolates were investigated using whole-genome sequencing (Illumina sequencing and nanopore sequencing), followed by analysis of virulence factors in the genomes and cultural properties of the isolates. The profile of S. aureus virulence genes (exotoxins, cytotoxins, superantigen-like proteins, adhesins) was identified via WGS. Hemolysin gene (hla) was detected in all isolates. An investigation of the cultural properties of the isolates, specifically through hemolysis of rabbit erythrocytes and Western blot analysis of the culture liquid of S. aureus, revealed different expression levels of alpha-hemolysin among the strains. One isolate (17-21) exhibited the highest secretion level of about 320 ± 37 ng, both in the hemolysis test and immunoblotting assay. An investigation of the isolates’ antibiotic resistance showed that all isolates exhibited multidrug resistance, as confirmed by the presence of antibiotic resistance genes in these isolates. One isolate (7-7) exhibited the broadest range of phenotypic resistance and was resistant to all tested antibiotics (except clindamycin). Phylogenetic analysis suggested that the evolution of these isolates occurred independently in their respective ecological niches, although their transfer from cattle to humans, and vice versa, is possible. Isolates 7-7, 18-22, 33-40, and 35-42 are most typical to Yakutian cattle, while isolate 17-21 might have been introduced from a different region. To the best of our knowledge, this is the first in-depth study into a range of S. aureus isolates associated with mastitis infection in Yakutian cattle. Full article

Thalassemia is a hereditary hemoglobinopathy characterized by ineffective erythropoiesis, chronic hemolysis, and transfusion-related iron overload, which collectively contribute to oxidative stress and organ dysfunction. The present study aimed to investigate the relationships between iron metabolism, oxidative stress biomarkers, and immune cell function across different clinical conditions. Peripheral blood samples were obtained from healthy individuals and patients with iron deficiency anemia, obesity, thalassemia trait (TT), β-thalassemia HbE (BTE), and β-thalassemia major (BTM). Hematological parameters were measured using automated hematology analyzers, while biochemical indicators, including liver enzymes and bilirubin, were determined using clinical chemistry assays. Iron overload was evaluated using serum iron parameters and T2*-weighted magnetic resonance imaging. Oxidative stress biomarkers, including reduced glutathione, thiobarbituric acid-reactive substances, and total antioxidant capacity, were assessed spectrophotometrically. Flow cytometric analysis was used to measure reactive oxygen species, redox-active iron, and lipid peroxide levels in granulocytes and lymphocytes. Thalassemia patients exhibited severe anemia, elevated liver enzymes, increased bilirubin levels, and significant alterations in iron metabolism compared with healthy controls. Hepatic iron accumulation was more common than cardiac iron deposition, particularly in BTE patients. Granulocyte oxidative burst activity was significantly reduced in thalassemia patients, whereas lymphocyte responses remained relatively preserved. Increased variability in glutathione levels suggested activation of intracellular antioxidant defense mechanisms in response to chronic oxidative stress. These findings highlight the complex interplay between iron overload, oxidative stress, and the immune cell dysfunction associated with thalassemia, thereby providing insights into improved monitoring and therapeutic strategies. Full article

Biosurfactant-producing microorganisms play an important ecological role in soils impacted by hydrophobic contaminants by enhancing substrate bioavailability and influencing microbial interactions. In this study, we critically evaluated the reliability of commonly used screening methods for biosurfactant detection. A total of 71 microbial isolates (16 bacteria and 55 fungi) were obtained from vegetable oil-contaminated soil and screened using a multi-step approach combining enzymatic assays (lipolytic and hemolytic activity) and physicochemical methods, including drop-collapse, oil spreading, emulsification index (E₂₄), and surface tension reduction. Although 21 isolates exhibited lipolytic activity and 9 showed hemolysis, inconsistent responses among assays revealed significant limitations of individual screening methods. Only two bacterial isolates consistently tested positive across all criteria. When cultivated in mineral salt medium supplemented with hydrophobic substrates, both isolates produced stable emulsions and significantly reduced surface tension (from 54.26 mN/m to 31.46 mN/m). Substrate-dependent variation was observed for isolate C3, which showed reduced surface tension (39.63 mN/m) when grown with biodiesel. These findings highlight the risk of relying on single assays and emphasize the need for integrated screening strategies to ensure reliable detection of biosurfactant-producing microorganisms. Full article

This study evaluated the hemolytic activity of Candida albicans isolates from the female reproductive tract and investigated the in vitro effects of quinalizarin on fungal growth, hemolysis, and ECE1 expression. Ninety-four clinical C. albicans isolates and three ATCC reference strains were analyzed. Hemolytic activity was quantified in culture supernatants and normalized per 10⁷ cells. Antifungal susceptibility and the effect of quinalizarin on hemolysis were assessed using broth microdilution and hemolysis assays. Expression of the ECE1 gene was evaluated by quantitative real-time PCR in three selected hemolytic strains. Drug interactions between quinalizarin and fluconazole were determined using the fractional inhibitory concentration index (FICI). Among the 97 tested strains, 78 exhibited hemolytic activity with variable intensity. Quinalizarin demonstrated antifungal activity, with MIC values ranging from 2 µg/mL to 256 µg/mL, and showed synergistic effects with fluconazole in selected strains. Exposure to quinalizarin at subinhibitory concentrations reduced ECE1 transcript levels to 22.8–73.6% of controls (p < 0.05) in the analyzed strains. However, the phenotypic effect on hemolysis was limited, with residual activity remaining high: 82% (p < 0.05), 93.7% (p < 0.05), and 83% (p < 0.05) relative to untreated controls in C. albicans ATCC 10231, ATCC 90028, and a clinical isolate, respectively. FICI analysis confirmed synergistic interactions between quinalizarin and fluconazole. This preliminary in vitro study highlights the need for further investigation into the relationship between ECE1 expression, candidalysin-mediated damage, and the antifungal potential of quinalizarin. Full article

Ventricular septal defect (VSD) occluders commonly rely on permanent nitinol frameworks, which may contribute to long-term mechanical mismatch and late complications. Here, we developed a tissue-compliant composite membrane by embedding a 3D-printed poly(vinyl alcohol) (PVA) grid within a shape-memory poly(glycerol dodecanedioate) (PGD) matrix. Grid spacing was varied from 0.1 to 0.5 mm to tune reinforcement density. FTIR indicated that PVA was incorporated mainly through physical interlocking rather than new covalent bonding. The composite preserved near-body-temperature shape recovery. In water at 37 °C, PVA reinforcement increased tensile modulus and fracture strength, although swelling also increased. Finite-element analysis and benchtop occlusion testing consistently showed lower deformation, less strain localization, and smaller bulge height for PGD–PVA than for PGD alone. In vitro assays showed low cytotoxicity, low hemolysis, and prolonged plasma recalcification time. A 12-week pilot degradation study showed that the faster mass loss observed in initial samples was mainly caused by exposed PVA cut edges; after switching to a fully encapsulated design, static mass loss became similar across groups, and dynamic PBS agitation produced about 10% mass loss at 12 weeks. These results support PGD–PVA as a reinforced membrane strategy for polymeric occluders. Full article

Background: Uropathogenic Escherichia coli (UPEC) is the primary etiological agent of urinary tract infections (UTIs) worldwide. The emergence of strains combining high virulence with multidrug resistance (MDR) poses a significant challenge to public health. This study aimed to characterize the phylogenetic distribution, virulence profiles, and antimicrobial susceptibility of UPEC isolates recovered from patients in the metropolitan area of Buenos Aires (AMBA), Argentina. Methodology: Phylogenetic groups, the ST131 lineage, and virulence-associated genes were identified using PCR-based assays. Antimicrobial susceptibility testing (AST) was performed using automated methods and extended-spectrum beta-lactamase (ESBL) production was confirmed using the double-disk synergy test. Colistin (COL) resistance was evaluated by Colistin Drop Test and PCR screening for the mcr-1 (mobile colistin resistance gene 1). Biofilm formation was detected by the Tissue Culture Plate (TCP) method, whereas phenotypic virulence factors (VF) were assessed with Congo Red agar, hemagglutination, and hemolysis assays. Results: Phylogenetic groups B2 (43.8%) and D (26.7%), typically associated with extraintestinal infections, were the most frequent. The high-risk clone B2-ST131 was detected in 6.7% of isolates. Biofilm production was observed in 92.4% of the isolates, with curli fimbriae (87.6%) being the most frequently expressed VF. The highest resistance rates were observed for ampicillin (62.1%), ampicillin-sulbactam (39.8%), and trimethoprim-sulfamethoxazole (25.2%). Interestingly, 3.8% of isolates exhibited colistin resistance, despite the absence of the mcr-1 gene. Conclusions: This study highlights the detection of MDR-UPEC isolates that showed strong resistance to fluoroquinolones and were ESBL producers with high virulence in Argentina, justifying future research encompassing genomic and epidemiological monitoring of local UPEC, which is essential for managing infections and developing new therapeutic and preventive measures. Full article

The continuous and rapid spread of African swine fever (ASF) still poses a significant threat to Eurasian wild boar and domestic pigs, leading to substantial economic losses in all associated sectors annually. In Europe, including Germany, affected wild boar populations have become an important driver and host of ASF virus (ASFV), and monitoring and surveillance is key to tailor control measures that impede viral spread. While molecular methods are used to confirm the disease and to monitor viral evolution, serology gains importance in endemically affected regions as it provides insights into disease dynamics and possible attenuation of ASFV strains. Frontline serological diagnosis is done using ELISA assays, of which several are commercialized. However, accurate performance of ELISA assays is key for correct interpretation of wild boar samples. Due to the various stages of hemolysis and decay, field samples from wild boar can be challenging for ELISA assays. To assess which indirect or competitive ELISA kit performs best when dealing with such samples, we compared the sensitivity and specificity of four commercially available ELISA kits that are licensed in Germany, as well as three unlicensed but commercially available kits. For this comparison, we used all wild boar samples submitted to the National Reference Laboratory (NRL) for ASF in years 2021 and 2022, as well as samples from domestic pigs to have a control cohort where sample quality is optimal. We observed that wild boar samples, varying in stage of hemolysis and decay, were challenging for all kits included in this study. However, samples of domestic pigs were largely interpreted correctly by ELISA, using immunoperoxidase test as verification method. Additionally, the comparability of results obtained by regional laboratories was high. Our study provides data that highlights the importance of careful kit selection, assessment of sample quality, and data interpretation for effective ASFV surveillance and control. Full article