Search Results (81)

Species of the Neltuma syn Prosopis genus are known for their use in traditional medicine in America, Asia and Africa. The use of the leaves, bark and inflorescences of one species widely distributed in the arid zones of Mexico, Neltuma laevigata (Humb. & Bonpl. Ex Willd) Britton & Rose, has been reported for the treatment of ocular, gastric and skin infections. Its activities have been related to different secondary metabolites, particularly phenylpropanoids and alkaloids. In the present study, the antibacterial activity of the alkaloidal fraction of inflorescences of P. laevigata collected in Zapotitlán Salinas, Puebla, México, against Staphylococcus aureus ATCC 25,923 and Vibrio cholerae CDBB-1159 was studied by Kirby–Baüer and broth microdilution tests, and its activity on plasmatic membranes was later identified using a protein leakage assay and fluorescence microscopy. Subsequently, the alkaloidal fraction was separated via chromatographic methods, and the purified compounds were elucidated using nuclear NMR and HRESIMS analysis. The alkaloidal fraction showed an important antibacterial activity, with a possible effect on the cytoplasmic membrane of the tested strains. Julifloridine, a piperidine alkaloid previously reported in the genus, was identified for the first time in this species. Full article

Ionic Liquids (IL) are a unique class of molten salts, with specific formulations exhibiting antimicrobial properties. Several recent studies have highlighted the ability of ILs to form micelles, permeabilize the plasma membrane, and destabilize cellular structure, ultimately initiating cell death. Moreover, while these membrane-destabilizing properties are cytotoxic to most cellular organisms at high concentrations, their membrane destabilization capability at lower concentrations may lead to improvements in drug delivery for combinatorial therapies against specific microbes. Work presented in this study aimed to identify a synergistic relationship between ILs, 1-n-Hexyl-3-methylimidazolium chloride (HMIM[Cl]) and 1-Methyl-3-n-octylimidazolium chloride (OMIM[Cl]), and antifungal drugs (AF), Clotrimazole, Ketoconazole, Fluconazole, and Itraconazole, with the hypothesis that in a combinatory setting there should be improved AF efficacy against model fungal organisms: S. boulardii, S. cerevisiae, S. pombe, and C. albicans. Several complementary assays were used to identify the combined effects of IL + AF treatment, including Kirby–Bauer tests and minimum inhibitory concentrations (MIC) assays to establish antimicrobial effects, and flow cytometry to evaluate cell wall permeability. Finally, we demonstrate that at low concentrations, the ILs tested in this study are capable of improving the effectiveness of current antifungal compounds at concentrations not cytotoxic to human cells. Full article

Background/Objectives: Salmonella enterica is a major cause of foodborne infection globally, with poultry acting as an important reservoir. However, data from Central Asia remain limited. This study provides preliminary phenotypic and genomic characterization of S. enterica isolates recovered from poultry farms in southern Kazakhstan, focusing on antimicrobial resistance (AMR), serotypes/sequence types and phylogenetic relationships. Methods: In October 2024, 335 poultry and environmental samples were collected from three regions of southern Kazakhstan using a cross-sectional, detection-focused sampling strategy. Isolation of Salmonella enterica followed enrichment and selective culturing, with confirmation by biochemical assays, slide agglutination serology and real-time PCR. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method and interpreted according to CLSI veterinary breakpoints (VET01/VET08) and CLSI M100 where veterinary criteria were unavailable. Whole-genome sequencing (Illumina) was used for in silico serotyping, MLST, AMR gene detection, plasmid replicon typing and SNP-based phylogenetic reconstruction. Results: Nine S. enterica isolates were confirmed (overall yield 2.7%; 9/335), comprising S. Enteritidis (ST11; n = 4), S. Infantis (ST32; n = 3) and ST68 (n = 2; Choleraesuis/Paratyphi C lineage). All isolates were resistant to ciprofloxacin, and most displayed resistance to ampicillin, gentamicin and trimethoprim-sulfamethoxazole. Plasmid-associated AMR determinants, including blaTEM-116, tet(A), sul1 and dfrA14, were frequently identified on IncF-type replicons. Phylogenetic analysis revealed that the isolates clustered with previously described Eurasian poultry-associated lineages. Conclusions: In this small, exploratory sample from poultry farms in southern Kazakhstan, all recovered S. enterica isolates were multidrug-resistant, with universal fluoroquinolone resistance and frequent plasmid-borne AMR genes. These preliminary findings provide baseline genomic evidence and highlight the need for broader, harmonized AMR surveillance in the regional poultry sector. Full article

This study presents a novel hydrogel formulation combining mupirocin, a broad-spectrum antibiotic, with keratinocyte growth factor (KGF) to enhance wound healing through antibacterial action and tissue regeneration. Mupirocin was encapsulated in hydroxypropyl β-cyclodextrin (HP-β-CD) and stabilized with poly(amidoamine) dendrimers (PAMAM). Molecular docking studies assessed mupirocin’s binding to PAMAM and its interaction with isoleucyl-tRNA synthetase. Physicochemical properties—including zeta potential, particle size, and surface tension—were characterized, and drug release kinetics were evaluated using Franz diffusion cells. In vitro assays on human dermal fibroblasts (HS27) included proliferation, scratch wound healing, and flow cytometry to assess cellular behavior. Antibacterial efficacy was determined via the Kirby–Bauer disk diffusion method. Results showed strong binding of mupirocin to its target enzyme, enhanced by KGF. The hydrogel exhibited favorable properties: surface tension of 24.7 dyne/cm, zeta potential of −24.79 mV, and particle size of ~119 nm, indicating high stability. Franz diffusion revealed sustained drug release compared to commercial mupirocin. Cellular assays demonstrated significant fibroblast migration and proliferation, with flow cytometry confirming increased wound healing markers. The formulation showed potent antimicrobial activity, including against Methicillin-resistant Staphylococcus aureus (MRSA), highlighting its promise for infected wound treatment and advanced clinical wound care. Full article

The use of electronic cigarettes has increased in the U.S. with menthol and mint flavors showing notably higher sales. While research on the bacterial microbiome of traditional tobacco products is growing, particularly regarding menthol and nicotine effects, data regarding potential microbial contaminants within electronic liquids (e-liquids) remain limited. Additionally, the potential antibacterial properties of e-liquids remain sparse. To address these gaps, we evaluated the prevalence of viable bacteria in e-liquids; characterized their antimicrobial susceptibility patterns; and tested the antibacterial activity of the e-liquids. Two e-liquid flavors (menthol and non-menthol) across three different nicotine concentrations (0, 6 and 12 mg/mL) were tested using culture-based methods and Sanger sequencing. Antimicrobial susceptibility testing and e-liquid antibacterial activity assays were performed using the Kirby Bauer disc diffusion method. The majority of the isolates (63.15%) were identified as Pseudomonas aeruginosa and Bacillus spp. (B. pumilus, B. megaterium and B. cereus). Notably, P. aeruginosa and P. fluorescens isolates exhibited multidrug resistance against penicillin, tetracyclines, and phenicols. The e-liquids also demonstrated antimicrobial activity, inhibiting the growth of B. cereus, P. aeruginosa, and Staphylococcus aureus, with greater inhibition of P. aeruginosa growth at higher (12 mg/mL) compared to lower (0 mg/mL) nicotine concentrations across the menthol-flavored samples. These findings offer preliminary evidence of viable, multidrug-resistant bacteria and antibacterial properties in e-liquids, underscoring potential public health concerns regarding user exposure risks and microbial interactions, and emphasizing the need for continued surveillance of microbial safety in electronic cigarette products. Full article

Background/Objectives: The widespread use of sulfamethoxazole (SMX) has led to increasing antibiotic resistance, and there is a need for improved formulations to enhance its therapeutic effectiveness. In this study, we investigated the biocidal potential of SMX composite crystals incorporated with functionalized poly(lactic-co-glycolic acid) (nfPLGA) and nano-graphene oxide (nGO). Methods: The composites, namely SMX-nfPLGA and SMX-nGO, were synthesized via antisolvent precipitation and evaluated using Kirby–Bauer disk diffusion assays. Results: Incorporation of nfPLGA and nGO significantly improved SMX solubility, increasing it from 0.029 mg/mL to 0.058 mg/mL and 0.063 mg/mL, respectively. Additionally, the log partition coefficient (log P or K_w) also improved from 1.4 to 0.86 for nGO and 0.92 for nfPLGA composites. Both formulations exhibited improved antibacterial activity with distinct time-dependent bactericidal effects. Compared to pure SMX, the SMX-nfPLGA showed 60% and 53% greater bacterial inhibition at concentrations of 50 mg/mL and 100 mg/mL, respectively. Although SMX-nGO was slightly less potent, it still surpassed pure SMX, with 50% and 33% higher inhibition at the same concentrations. Conclusions: Importantly, neither nfPLGA nor nGO showed any biocidal effects, confirming that the observed enhancement was due to improved SMX solubility caused by their incorporation. These findings suggest that embedding solubility-enhancing nanoparticles into the existing crystal structure of the antibiotic is a promising strategy for enhancing the effectiveness. Full article

Beta (β)-type Ti-29Nb-13Ta-4.6Zr (TNTZ) alloys combine low modulus with biocompatibility but require improved surface properties for long-term implantation. This study aimed to enhance the surface mechanical strength and antibacterial performance of TNTZ by applying TiN and TiAlN coatings via PVD. Notably, TiAlN was deposited on TNTZ for the first time, enabling a direct side-by-side comparison with TiN under identical deposition conditions. Dense TiN (~1.06 μm) and TiAlN (~1.73 μm) coatings were deposited onto solution-treated TNTZ and characterized by X-ray diffraction, scanning probe microscopy, Vickers microhardness, Rockwell indentation test (VDI 3198), static water contact angle measurements, and a Kirby–Bauer disk-diffusion antibacterial assay against Escherichia coli (E. coli). Both coatings formed face-centered cubic (FCC) structures with smooth interfaces (Ra ≤ 5.3 nm) while preserving the single-phase β matrix of the substrate. The hardness increased from 192 HV (uncoated) to 1059 HV (TiN) and 1468 HV (TiAlN), and the adhesion quality was rated as HF2 and HF1, respectively. The surface wettability changed from hydrophilic (48°) to moderately hydrophobic (82°) with TiN and highly hydrophobic (103°) with TiAlN. Similarly, the diameter of the no-growth zones increased to 18.02 mm (TiN) and 19.09 mm (TiAlN) compared to 17.65 mm for uncoated TNTZ. The findings indicate that TiAlN, in particular, provided improved hardness, adhesion, and hydrophobicity. Preliminary bacteriostatic screening under diffusion conditions suggested a modest relative antibacterial response, though the effect was not statistically significant between coated and uncoated TNTZ. Statistical analysis confirmed no significant difference between the groups (p > 0.05), indicating that only a preliminary bacteriostatic trend— rather than a definitive antibacterial effect—was observed. Both nitride coatings strengthened TNTZ without compromising its structural integrity, making TiAlN-coated TNTZ a promising candidate for next-generation orthopedic implants. Full article

Background/Objectives: The rise of multidrug-resistant bacteria and fungi, or “superbugs”, makes the development of new antimicrobial compounds of continued importance. In this context, we have explored structural variants of the plant-derived phytocompound berberine, seeking higher antimicrobial activity and selectivity. Our prior work prepared fourteen protoberberine variants (B1–B14), and found that a partially reduced dihydro-protoberberine (B14) was significantly more active against Gram-positive bacteria. To further investigate this trend, we prepared a series of protoberberines and related dihydro-protoberberines, with the goal of better understanding the effects of the partial reduction of the protoberberine core. Methods: Protoberberines were prepared from a cyclization between glyoxal and substituted N-benzyl-phenethylamines, prepared by reductive amination. Dihydro-derivatives were obtained via NaBH₄ reduction. Biological activity was assessed with a Kirby–Bauer assay to determine zones of inhibition against a panel of twelve microorganisms. Cytotoxicity was also assessed using an MTT assay against a T84 human colon carcinoma cell line. Results: The majority of the prepared compounds showed greater Gram-positive antibacterial activity compared to original berberine, and nearly all dihydro-protoberberines had improved Gram-positive antibacterial activity over their unreduced form. Additionally, the reduced variants were less active against fungi, indicating a step towards higher microbial selectivity. All variants showed greater potency against cancer cells. Conclusions: The present work highlights a significant improvement in antibacterial activity and selectivity for this set of dihydro-protoberberines over their unreduced counterparts. Full article

Electrospun nanofibers have emerged as a versatile platform for developing advanced materials with diverse applications, owing to their high surface-area-to-volume ratio and tunable properties. The incorporation of metal oxide nanoparticles, such as titanium dioxide (TiO₂), has proven effective in further enhancing the functional performance of these materials, particularly in optoelectrical, antibacterial, and antioxidant domains. This study presents the first report of electrospun multifunctional nanofibers from a ternary blend of polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), and polyacrylamide (PAAm) blended with TiO₂ nanoparticles at 0, 1, 3, and 5 wt.%. The objective was to develop nanocomposites with enhanced structural, optical, electrical, antibacterial, and antioxidant properties for applications in environmental, biomedical, and industrial fields. The nanofibers were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy (FTIR), UV–visible spectrophotometry, and DC electrical conductivity tests. Antibacterial efficacy was assessed against Escherichia coli and Staphylococcus aureus via the Kirby–Bauer disk diffusion method, while antioxidant activity was evaluated using the DPPH radical scavenging assay. Results demonstrated that TiO₂ incorporation increased nanofiber diameters (21.5–35.1 nm), enhanced crystallinity, and introduced Ti–O bonding, confirming successful nanoparticle integration. Optically, the nanocomposites exhibited reduced band gaps (from 3.575 eV to 3.320 eV) and increased refractive indices with higher TiO₂ nanoparticle content, highlighting their potential for advanced optoelectronic devices such as UV sensors and transparent electrodes. Electrically, conductivity improved due to increased charge carrier mobility and conductive pathways, making them suitable for flexible electronics and sensing applications. The 5 wt.% TiO₂-doped nanofibers demonstrated superior antibacterial activity, particularly against E. coli (18.2 mm inhibition zone), and antioxidant performance comparable to ascorbic acid (95.32% DPPH inhibition), showcasing their relevance for biomedical applications like wound dressings and food packaging. These findings highlight the potential of PVA-PVP-PAAm/TiO₂ nanofibers as useful materials for moisture sensors, antibacterial agents, and antioxidants, advancing applications in medical devices and environmental technologies. Full article

This study evaluated the antioxidant and antibacterial potential of Passiflora edulis (passion fruit) at three ripening stages—intermediate, ripe, and overripe—to determine the optimal consumption time based on the presence of secondary metabolites (polyphenols, alkaloids, and anthocyanins). Fruits from Costa Rica, including pulp and peel, were analyzed. Qualitative assays (Dragendorff, Mayer, Lieberman Burchard, Ferric Chloride, and Shinoda) and quantitative analyses using Folin–Ciocalteu (total polyphenols), ORAC (antioxidant activity), and Kirby–Bauer (antibacterial activity) methods were conducted. Acetone–water (7:3) was the most effective solvent, with three extractions yielding optimal results. Peels contained significantly higher polyphenols (7.2 ± 0.1 mg GAE/g d.w.) and antioxidant activity (2403 ± 519 µmol TE/g d.w.) than pulps. Anthocyanins were abundant in both, while antibacterial activity was more effective in peels, inhibiting Gram-positive bacteria with 25% relative inhibition, but showing no activity against Gram-negative strains. These findings highlight passion fruit peel as a rich source of bioactive compounds with strong antioxidant and antibacterial properties, particularly in intermediate and overripe stages, supporting its potential use in the development of functional ingredients for nutraceutical applications and promoting sustainable waste management. Full article

Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4), threatens banana and plantain production throughout South America. Because Colombian biosafety regulations restrict in vitro work with Foc TR4, we tested the antifungal activity of Nostoc commune against F. oxysporum race 2 isolated from cv. ‘Manzano’ (Musa AAB). An ethanolic extract of the cyanobacterium (EEC) was profiled by gas chromatography and evaluated with a Kirby–Bauer assay (1000–4000 ppm; n = 4). Synthetic Sico^® and botanical Timorex^® served as positive controls, and solvent-free plates were the negative control. Growth reduction (GR) and percentage inhibition of radial growth (PIRG) were analysed with Student’s t-test (α = 0.05). Forty-two compounds—mainly fatty and carboxylic acids associated with antifungal activity—were detected. Sico achieved complete inhibition (100 ± 0%), Timorex suppressed 76 ± 2%, and 4 000 ppm EEC curtailed mycelial expansion by 45 ± 3% (p < 0.01). Although less potent than commercial fungicides, EEC impeded F. oxysporum growth, demonstrating that N. commune synthesises bioactive metabolites. Optimising cyanobacterial cultivation and formulation could yield a sustainable biocontrol alternative for managing Fusarium wilt in the region. Full article

Urogenital infections contribute greatly to both hospital- and community-acquired infections. In Ghana, the prevalence of resistance to commonly used antibiotics is relatively high. This study sought to evaluate the antibiotic sensitivity of bacterial urogenital pathogens from patient samples in a regional and district hospital in the Volta Region of Ghana. A retrospective cross-sectional study was conducted using data obtained between January and December 2023 from Volta Regional Hospital and Margret Marquart Catholic Hospital. Bacteria were isolated from urine, urethral swabs, and vaginal swabs from 204 patients. Data on culture and sensitivity assays performed using the Kirby–Bauer disc diffusion method were extracted and analyzed using WHONET. The most prevalent organisms isolated from the samples from both facilities were Escherichia coli (24.9%), Staphylococcus aureus (21.5%), and Klebsiella oxytoca (8.8%). The isolates were mostly resistant to amoxicillin/clavulanic acid (n = 75, 95% CI [91.8–99.9]), meropenem (n = 61, 95% CI [87.6–99.4]), cefuroxime (n = 54, 95% CI [78.9–96.5]), ampicillin (n = 124, 95% CI [61.2–77.9]), and piperacillin (n = 43, 95% CI [82.9–99.2]). Multidrug-resistant (MDR, 70 (34.1%)), extensively drug-resistant (XDR, 63 (30.7%)), and pandrug-resistant (PDR, 9 (4.3%)) strains of S. aureus, E. coli, and Pseudomonas aeruginosa were identified from the patient samples. The study highlights the presence of high-priority resistant urogenital pathogens of public health significance to varied antibiotic groups. Full article

In this work, κ-carrageenan (κ-C) and polyethylene oxide (PEO) were utilized to synthesize polymeric films (κ-C-PEO). A 2^k experimental design was employed to optimize the synthesis of κ-C-PEO systems by considering the content of κ-carrageenan, PEO, and glycerin and their influence on the mechanical features of the resultant films. The κ-C-PEO systems were robustly characterized by FTIR spectroscopy, thermogravimetric analyses, and scanning electron microscopy (SEM). Magnesium oxide nanoparticles (MgO-NPs) were utilized to load κ-C-PEO films as an efficient approach to enhance their biological performance. The activity of κ-C-PEO films was studied against Gram-negative bacteria through the Kirby–Bauer assay. Artemia salina nauplii were cultured to assess the possible toxicity of κ-C-PEO films. The results demonstrated that κ-C-PEO films were elongated with the heterogeneous distribution of MgO-NPs. The tensile strength, thickness, and swelling capacity of κ-C-PEO films were 129 kPa, 0.19 mm, and 52.01%, respectively. TGA and DTA analyses revealed that κ-C-PEO films are thermally stable structures presenting significant mass loss patterns at >200 °C. Treatment with κ-C-PEO films did not inhibit the growth of Escherichia coli nor Pseudomonas aeruginosa. Against A. salina nauplii, κ-C-PEO films did not decrease the survival rate nor compromise the morphology of the tested in vivo model. The retrieved data from this study expand the knowledge about integrating inorganic nanomaterials with polysaccharide-based structures and their possible application in treating chronic wounds. Even though this work provides innovative insights into the optimal design of bioactive structures, further approaches are required to improve the biological performance of the synthesized κ-C-PEO films. Full article

Introduction: Listeria monocytogenes is the causative agent of listeriosis, a serious infectious disease with one of the highest case fatality rates among foodborne diseases affecting humans. Objectives: This study investigated the prevalence, antimicrobial resistance pattern and biofilm production capacity of L. monocytogenes isolated in meats. Materials: A total of 75 samples were analyzed, including fresh meats and meat preparations, in Northern Portugal. Methods: The strains were identified using morphological and molecular methods. Antimicrobial resistance was determined using the Kirby–Bauer disk diffusion method, against a panel of 12 antibiotics and the presence of the respective antimicrobial resistance genes was investigated by polymerase chain reaction (PCR). The ability to form biofilms was evaluated by the microtiter biofilm assay. Results: The overall prevalence of L. monocytogenes among screened samples was 17.33%. The isolates were resistant to trimethoprim-sulfamethoxazole (85.71%), ciprofloxacin (38.10%), meropenem (33.33%), tetracycline and erythromycin (28.57%), rifampicin (23.81%), and kanamycin (14.29%). Six isolates (28.57%) exhibited a multidrug-resistance profile. All strains showed positive result for the virulence gene specific to listeriolysin O (hlyA). In the genotypic resistance analysis of the strains, the genes identified were tetK (23.81%), aadA, tetL, bla_OXA-48 (14.29%), ermC, and msr(A/B) (4.76%). All isolates had the ability to form biofilms, with no significant differences in biofilm biomass production at 24 h and 48 h. Some of these strains showed a high capacity for biofilm production. Conclusions: These findings raise public health concerns due to resistance to first-line antibiotics and the biofilm-forming capacity of these isolates, which pose risks to the food industry. Enhanced monitoring and surveillance are essential to guide public health strategies in order to mitigate the threat posed by L. monocytogenes in food. Full article

Campylobacter spp. represents one of the most frequently incriminated pathogens in the evolution of foodborne gastroenteritis in humans worldwide. Alongside Salmonella spp., Yersinia spp., Escherichia coli, and Listeria monocytogenes, these pathogens represent a principal threat to public health because they are vehiculated to humans via food products and many of them have developed alarming resistance to different classes of antimicrobials. Thus, the present study aimed to provide scientifically relevant data on the public health risk represented by Campylobacter spp., contamination of chicken carcasses at the slaughterhouse and retail levels, and the antimicrobial resistance of the isolated strains. A total of 130 samples collected from slaughterhouses (n = 40) and retail stores (n = 90) were analyzed using standardized microbiological methods (ISO 10272-1:2017). Of these, the overall prevalence of Campylobacter spp. was 27.7%, with a prevalence at the slaughterhouse level of 32.5% and at the retail level of 25.5%. Following antimicrobial resistance profile determinations using the Kirby–Bauer disc diffusion assay, the isolated strains showed resistance to the following antimicrobials in descending order: ciprofloxacin (41.6%), tetracycline (25.0%), chloramphenicol (16.6%), gentamicin (11.1%), ertapenem (5.6%), and erythromycin (2.8%). The study results confirm that chicken meat may pose a threat to public health and, moreover, that due to the widespread use of antimicrobials, a large number of strains have developed antimicrobial resistance, leading to difficulties in the treatment of various foodborne diseases. Full article