Search Results (7,094)

Geraniol (GA) is a terpene compound of natural origin that exhibits strong biological activity. The possibility of using GA as a potential compound with antimicrobial activity is currently of great interest to scientists. The aim of the present study was to comprehensively evaluate the activity of GA against selected strains of Gram-positive bacteria, Gram-negative bacteria, and fungi that pose a significant threat in clinical practice. Among the Gram-positive bacteria studied were Streptococcus spp., Neisseria gonorrhoeae, and Listeria monocytogenes. Among the Gram-negative bacteria tested were Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. The fungal pathogens analyzed included Candida albicans and Candida glabrata. The results showed that GA exhibited strong antimicrobial activity against most of the microorganisms tested. Gram-positive strains were more susceptible to GA compared to Gram-negative strains, probably due to differences in cell wall structure. In the case of fungi, significant efficacy was noted against Candida albicans. This study confirms the potential of GA as an alternative antimicrobial agent, especially against antibiotic-resistant bacterial strains and fungal pathogens. These results open up new perspectives for the application of GA in medicine and the pharmaceutical industry. The study on creams demonstrated that GA possesses strong antimicrobial properties, effectively inhibiting bacterial growth regardless of the concentration used (0.5–12%) and the type of culture medium, confirming its potential as a natural preservative agent in the cosmetic and pharmaceutical industries. Moreover, the research on the anticancer activity of GA revealed its cytotoxic effects against colon cancer cells (LoVo cell line, IC₅₀ = 32.1 μg/mL) and glioma cells (U87 cell line, IC₅₀ = 41.3 μg/mL), particularly at higher concentrations, indicating its promising therapeutic potential. Full article

Introduction: Scrub typhus is caused by Gram-negative bacteria, Orientia tsutsugamushi. Humans are the dead-end host of scrub typhus. Currently, there is no vaccine available. The disease can be fatal without appropriate treatment. Here, we present the circulating OT genotypes in Malaysia and a tsa56-based single PCR to detect and determine OT genotypes, which is an approach to replace the time-consuming traditional nested PCR. Methods: The patients’ blood or tissue samples (n = 1200), received from all hospitals in Malaysia from December 2022 to November 2024, were screened for rickettsial infections. Both htrA qPCR and nested PCR were performed to detect the presence of OT DNA. Simultaneously, a selection of DNA was evaluated for the new single PCR protocol and confirmed with Sanger sequencing. Results: We report that Pahang state of Peninsular Malaysia presents the highest number of acute scrub typhus infections in Malaysia within the 24 months period. There are four genotypes circulating in the Malaysian population. OT genotype Gilliam (n = 31, 29.2%) and Karp (n = 31, 29.2%) are the predominant OT genotypes in Malaysia, followed by TA763 (n = 22, 20.8%) and Kato (n = 22, 20.8%). The single-run PCR presents longer sequence size and similar results with the nested PCR. Conclusions: Acute scrub typhus infection is not rare in Malaysia and should be considered for undifferentiated febrile illness. The single-run PCR protocol is time-saving and a promising approach for OT detection and genotype analysis in a single run to complement a clinical diagnostic setting and surveillance. Full article

In this article, the binding interactions of lysozyme with hexacyanoferrate(III)/(II), i.e., [Fe(CN)₆]³⁻ and [Fe(CN)₆]⁴⁻ ions, have been characterised using steady-state fluorescence spectroscopy (SF), isothermal titration calorimetry (ITC), circular dichroism spectroscopy (CD), cyclic voltammetry (CV), and molecular-dynamics-based computational approaches. Studies have shown that under experimental conditions (10 mM cacodylate buffer, pH 7, 298.15 K), complexes with a 1:1 stoichiometry are formed. Four distinct regions on the lysozyme surface patches with the potential to bind hexacyanoferrate(III)/(II) were identified and described. Thermodynamic parameters revealed that the interactions are predominantly governed by electrostatic and van der Waals forces. These interactions enhance the electron transfer kinetics of the [Fe(CN)₆]^3−/4− system. The secondary structure of the protein is not affected by these interactions. Enzyme activity studies demonstrated that the affinity of lysozyme for the substrate remained unchanged regardless of whether free lysozyme or the lysozyme-[Fe(CN)₆]^3−/4− complex was present in the test sample. Finally, biological tests performed on both Gram-positive (B. subtilis, S. aureus) and Gram-negative (E. coli, P. aeruginosa) bacteria confirmed the results of the biochemical analysis, indicating that [Fe(CN)₆]^3−/4− ions do not block the active site of the enzyme and do not interfere with its activity. Full article

As aquaculture expands globally, understanding immune responses in non-traditional farmed species like Octopus vulgaris under varying environmental conditions is increasingly important. This study investigated lysozyme activity, a key innate immune marker, in cell-free hemolymph of O. vulgaris following experimental challenge with four Gram-negative fish pathogens (Photobacterium damselae subsp. piscicida, P. damselae subsp. damselae, Vibrio alginolyticus, and V. anguillarum O1) at two temperatures (21 ± 0.5 °C and 24 ± 0.5 °C). These pathogens were selected because octopus farming frequently occurs near fish aquaculture facilities, raising the potential for pathogen crossover. A total of 216 wild octopuses were injected intramuscularly or intravenously and sampled on days 0, 3, and 7 post-challenge. Lysozyme activity varied by pathogen, injection route, sampling time, and temperature. A significant time- and temperature-dependent increase was observed, especially in IM-challenged groups exposed to Photobacterium species. Elevated temperatures supported a more prolonged immune response. These results highlight lysozyme as a responsive biomarker of innate immunity in O. vulgaris and emphasize the role of environmental factors in immune modulation. This work provides a foundation for disease monitoring and health management in cephalopod aquaculture. Future research should examine long-term lysozyme dynamics, broader pathogen exposure, molecular mechanisms, and additional environmental stressors such as salinity and pollution. Full article

This paper investigates the effectiveness of Word2Vec-based molecular representation learning on SMILES (Simplified Molecular Input Line Entry System) strings for a downstream prediction task related to the market approvability of chemical compounds. Here, market approvability is treated as a proxy classification label derived from approval status, where only the molecular structure is analyzed. We train character-level embeddings using Continuous Bag of Words (CBOW) and Skip-Gram with Negative Sampling architectures and apply the resulting embeddings in a downstream classification task using a multi-layer perceptron (MLP). To evaluate the utility of these lightweight embedding techniques, we conduct experiments on a curated SMILES dataset labeled by approval status under both imbalanced and SMOTE-balanced training conditions. In addition to our Word2Vec-based models, we include a ChemBERTa-based baseline using the pretrained ChemBERTa-77M model. Our findings show that while ChemBERTa achieves a higher performance, the Word2Vec-based models offer a favorable trade-off between accuracy and computational efficiency. This efficiency is especially relevant in large-scale compound screening, where rapid exploration of the chemical space can support early-stage cheminformatics workflows. These results suggest that traditional embedding models can serve as viable alternatives for scalable and interpretable cheminformatics pipelines, particularly in resource-constrained environments. Full article

The emergence of bacterial resistance has spurred an urgent need to develop effective alternatives to traditional antibiotics. Phenylethyl alcohol from plants exhibits potential antimicrobial properties, but its efficacy is limited due to its compromised dispersion in water and structural stability in ambient conditions. Herein, for the first time, a polymerization-induced self-assembly strategy was employed to obtain different morphological nanogels with phenylethyl alcohol moieties as hydrophobic cores through in situ reversible addition–fragmentation chain-transfer (RAFT) polymerization. The well-defined copolymers of PTEG_x-co-PPMA_y with controllable molecular weights and narrow polydispersity were confirmed by a combination of techniques. The generated phenylethyl alcohol-based nanogels demonstrated potent antibacterial activity, particularly PTEG₃₀-co-PPMA₇₀ with a one-dimensional linear architecture, which achieved a minimum inhibitory concentration of 62 μg mL⁻¹ against E. coli. SEM revealed membrane disruption as the bactericidal mechanism, highlighting enhanced efficacy against Gram-negative bacteria due to structural differences in cell envelopes. This study establishes a robust platform for designing phenylethyl alcohol-based nanogels with controllable structures toward achieving potent antimicrobial performance, offering a promising strategy for combating bacterial resistance while addressing the dilemma of conventional antibiotic drug systems. Full article

Nanoporous gold nanoparticles (np-AuNPs) combine inertness, a nanoscale structure, and a porous framework with high surface area, conductivity, and biocompatibility, making them ideal for biosensing, catalysis, fuel cells, and drug delivery. Their open pore structure and low-coordinated atoms enhance biomolecule capture and mass transfer, while their tunable size, pore volume, and ease of surface modification make them promising biosensor transducers. However, synthesizing colloidal np-AuNPs in a simple way with controllable size and scalability remains challenging. The existing approaches mostly rely on specialized equipment, complex setups, and expert knowledge, while still facing challenges in terms of scalability. In this study, we present a simple, seedless, wet-chemical synthesis of colloidal np-AuNPs via the co-reduction of Au/Ag alloys followed by dealloying. By adjusting the Au:Ag ratio, we produced np-AuNPs sized ~120–530 nm, which were immobilized on electrodes for detecting lipopolysaccharide (LPS), a toxic component of Gram-negative bacterial membranes. The LPS biosensor exhibited excellent sensitivity towards detecting wild-type LPS, with a low limit of detection (LOD) of 0.1244 ng/L. This work demonstrates the effective synthesis and application of np-AuNPs in LPS biosensing. Full article

This study presents the development of a degradable and biocompatible calcium phosphate cement (CPC) co-loaded with gentamicin (1.25 wt%) and vancomycin (4.25 wt%) for the local treatment of polymicrobial bone infections. The antibiotics were incorporated—individually or in combination—into the solid phase of Graftys^® Quickset (GQS), an injectable CPC. Antibiotic loading modifies some of the intrinsic properties of the GQS cement. Porosity exceeded 53%, compressive strength reduced around 5 MPa, which is comparable to calcium sulphates cements, and the setting time, although extended, remained within the clinically acceptable threshold (<20 min), ensuring suitable handling. A burst release of both antibiotics was observed within the first 24 h, with sustained release over time and no cytotoxic effects on human osteoblasts. The dual-loaded cement exhibited broad-spectrum antibacterial activity against both Gram-positive and Gram-negative strains, including methicillin-resistant isolates, in both planktonic and biofilm forms. Notably, the combination of both antibiotics demonstrated superior efficacy compared to either antibiotic alone. These findings suggest that this dual-antibiotic-loaded CPC offers a promising strategy for localised treatment of complex bone infections such as osteomyelitis, where polymicrobial involvement and antibiotic resistance pose significant therapeutic challenges. Full article

Background/Objectives: The rise in antibiotic resistance presents a serious and urgent global health challenge, emphasizing the need to develop new therapeutic compounds. This study focuses on the design and evaluation of a novel series of hybrid molecules that combine the 2-quinolone and 1,2,3-triazole pharmacophores, both recognized for their broad-spectrum antimicrobial properties. Methods: A library of 29 candidate molecules was first designed using in silico techniques, including QSAR modeling, ADMET prediction, molecular docking, and molecular dynamics simulations, to optimize antibacterial activity and drug-like properties. The most promising compounds were then synthesized and characterized by ¹H and ¹³C NMR APT, mass spectrometry (MS), Fourier-transform infrared (FT-IR) spectroscopy, and UV-Vis spectroscopy. Results: Antibacterial evaluation revealed potent activity against both Gram-positive and Gram-negative bacterial strains, with minimum inhibitory concentration (MIC) values ranging from 0.019 to 1.25 mg/mL. Conclusions: These findings demonstrate the strong potential of 2-quinolone–triazole hybrids as effective antibacterial agents and provide a solid foundation for the development of next-generation antibiotics to combat the growing threat of bacterial resistance. Full article

Background: Periprosthetic joint infection (PJI) is one of the most serious complications following total joint arthroplasty. The debridement, antibiotics, irrigation, and implant retention (DAIR) procedure is commonly employed to treat acute, early-stage infections, but its success is highly variable, influenced by factors such as pathogen virulence and antibiotic susceptibility profiles. This study aimed to evaluate the impact of pathogens responsible for these infections on the outcome of DAIR. Methods: This retrospective, single-center study analyzed the microbiological profiles of 116 patients (66 hips and 50 knees) treated for acute periprosthetic joint infections (PJIs) with DAIR between 2018 and 2022. Acute PJI was defined as a duration of symptom less than three weeks, according to the criteria established by the Tsukayama and Izakovicova classification. Preoperative joint aspirations, intraoperatively collected tissue samples, and sonication of the exchanged mobile parts were analyzed for each case. We differentiated between monomicrobial PJI, polymicrobial PJI (defined as the identification of more than one microorganism from preoperative joint fluid aspiration or intraoperative samples), and difficult-to-treat (DTT) pathogens. Results: In this cohort, the following pathogen profiles were identified: culture-negative cases accounted for 11.1% of infections, while 64.2% were attributed to Gram-positive bacteria, 19.8% to Gram-negative bacteria, and 4.9% to fungal pathogens. Among the identified microorganisms, coagulase-negative staphylococci (CNS) were the most frequently detected, exhibiting a notable oxacillin resistance rate of 52.9% and rifampicin resistance rate of 28.7%. Additionally, no significant difference in revision-free implant survival was found between patients with DTT pathogens and/or polymicrobial PJI and those without such infections. Conclusions: This study highlights that pathogens in prosthetic joint infections (PJIs) do not solely determine outcomes, as patient-specific factors (comorbidities, implant type) may also play a key role. Regional variations in pathogens and antibiotic resistance patterns should guide empirical therapy. For instance, this study found a high reliance on vancomycin due to high oxacillin resistance in CNS, the most frequent causative pathogen. Full article

Two proline-rich antimicrobial peptides (PrAMPs), named P1 and P2, purified from hemolymph of the greater wax moth Galleria mellonella, were studied for their effects on Gram-negative (Escherichia coli) and Gram-positive (Micrococcus luteus) bacteria. Both peptides decreased the M. luteus bacterial survival rate and caused E. coli bacterial membrane permeabilization. However, in both cases, the P2 peptide was approximately three times more effective than the P1 peptide. Fluorescence microscopy imaging demonstrated binding of both FITC-labeled peptides to E. coli and M. luteus cells. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) imaging of peptide-treated bacteria revealed considerable changes in cell morphology, cell surface topography, and nanomechanical properties. The interactions of the PrAMPs with bacterial cells were also analyzed by FTIR spectroscopy. The P1 peptide action toward E. coli led to partial aggregation of proteins, whereas treatment with P2 resulted in reduced protein aggregation, reflecting differences between both G. mellonella PrAMPs antibacterial action. Moreover, both PrAMPs caused a decrease and an increase in the protein content in relation to lipids on the E. coli and M. luteus cell surface, respectively. The obtained results reflect not only differences between the G. mellonella P1 and P2 peptides but also differences in the cell surface between Gram-negative and Gram-positive bacteria. Both characterized G. mellonella PrAMPs are further representatives of proline-rich peptides with a membrane-permeabilizing antimicrobial mode of action. Full article

The demand for antimicrobial and biocompatible materials in biomedical applications continues to grow, particularly in the context of wound care and textiles. This study explores the development of multifunctional coatings by applying magnesium (Mg) nanoparticles onto medical-grade cotton textiles using magnetron sputtering—a solvent-free and environmentally sustainable technique. A comprehensive material characterization confirmed the formation of Mg, MgO and Mg(OH)₂/MgH₂ phases, along with generally consistent particle coverage and increased fiber surface roughness. The antibacterial testing revealed the effective inhibition of both Gram-positive and Gram-negative bacteria—except Enterococcus faecalis. Additionally, the growth of the fungus Candida albicans and the microalgae Prototheca spp. was reduced by over 80%. Importantly, a cytocompatibility evaluation using human umbilical vein endothelial cells (HUVECs) demonstrated not only non-toxicity but a significant increase in cell viability after 72 h, particularly in samples treated for 20 and 60 min, indicating a potential cytoprotective and proliferative effect. These findings highlight the dual functionality of plasma-sputtered Mg nanoparticle coatings, offering a promising strategy for the development of eco-friendly, antimicrobial and cell-supportive medical textiles. Full article

The cellular envelope of Gram-negative bacteria is a space where processes that are extremely important for the proper functioning of bacteria and determining their virulence take place. The extracytoplasmic protein quality control system, which includes chaperones, protein-folding catalysts, and proteases, is responsible for maintaining homeostasis in this cellular compartment. This system has been well studied in the model bacterium Escherichia coli, but little is known about its function in other bacteria. In bacteria evolutionarily distant from Enterobacteriaceae, the protein quality control system appears to function differently. For example, in the phylum Campylobacterota, a number of homologs of folding factors and proteases, whose functions are important for maintaining homeostasis in the periplasm of E. coli, have not been identified. Instead, there are quality control components that have no similar counterparts in the Enterobacteriaceae. In this review, we present the current state of knowledge on the extracytoplasmic protein quality control system in the model Campylobacterota, C. jejuni and H. pylori. Full article

This study aimed to identify bacterial isolates associated with mortality events in Salmo trutta rearing farms in Spain and to assess their antibiotic resistance profiles. The analysis covered five fish farms: two with a recent history of antibiotic use and three without any antibiotic application in the six months prior to sampling. Tissue samples were collected from moribund fish displaying clinical signs such as erratic swimming, ocular hemorrhages, fin hemorrhages, and skin lesions during disease outbreaks in 2022 and 2023. The samples were analyzed using real-time PCR, amplification and sequencing of the 16S rRNA gene and the ITS-1 intergenic spacer, and MALDI-TOF mass spectrometry. A total of 19 bacterial isolates were identified, with Gram-negative bacteria, particularly Aeromonas spp., being the most prevalent. Other identified taxa included Plesiomonas sp., Hafnia alvei, Pseudomonas fulva, and Kluyvera intermedia, as well as Gram-positive species such as Carnobacterium maltaromaticum, Lactococcus sp., and Enterococcus faecium. Notably, resistant strains were found in four of the five farms, even in those that had not administered antibiotics, suggesting that environmental contamination and anthropogenic factors may significantly contribute to the spread of resistance. Environmental stressors—such as sudden increases in water temperature and high turbidity caused by suspended organic matter—appeared to precede mortality peaks. The findings highlight the role of Aeromonas spp. as a key bacteria associated with mortality events in S. trutta and underscore the multifactorial nature of antibiotic resistance in aquaculture. No florfenicol-resistant isolates were detected in the farms where it is routinely used, indicating that florfenicol remains an effective antibiotic in aquaculture. However, the continuous and systematic monitoring of its use remains essential. The detection of bacteria not traditionally associated with fish pathology in samples from diseased animals suggests the need for further studies into their pathogenic potential. Overall, this descriptive study emphasizes the importance of preventive health strategies, prudent antibiotic use, and environmental monitoring to mitigate bacterial diseases and limit the spread of antimicrobial resistance in brown trout farming. These findings align with a One Health perspective, linking aquaculture practices, ecosystem integrity, and public health. Full article

Background: Spontaneous bacterial peritonitis (SBP) represents a significant complication of liver cirrhosis; Gram-positive bacteria (GPB) predominance was recently noted in some areas, with increased antibiotic resistance. Etiology and mortality prediction are important in culture-negative SBP and for empirical antibiotherapy before the arrival of culture results. Methods: A retrospective study was performed on patients with cirrhosis and ascites admitted between 2018 and 2024, divided into culture-positive SBP (Gram-positive and Gram-negative), culture-negative SBP, and non-infected ascites. The NLR (neutrophil-to-lymphocyte ratio) accuracy for the prediction of SBP and in-hospital mortality was estimated using ROC analysis. Results: Overall, 45 culture-positive SBP, 28 culture-negative SBP, and 600 control ascites were diagnosed; Gram-positive SBP represented 60%; median NLR values were significantly higher in patients with Gram-negative compared with Gram-positive SBP (8.79 in Gram-negative versus 3.92 in Gram-positive SBP, AUC 0.752, p = 0.003); and a limited role in SBP prediction was recorded (AUC 0.642, p = 0.003), with no difference between culture-positive and culture-negative SBP. The NLR median values were higher for patients who died in hospital in all patients with cirrhosis, in SBP, and culture-positive SBP, but not in culture-negative SBP. Conclusions: Higher NLR values were associated with Gram-negative SBP etiology and with in-hospital mortality in all cirrhosis, in SBP, and especially in culture-positive and Gram-negative SBP cases. High NLR values can predict the Gram-negative etiology in patients with an ascitic neutrophil count above 250/mm³, which can be used to guide empirical antibiotherapy until cultures are available or in culture-negative SBP. Full article