Search Results (548)

Salmonella is one of the main causes of food-borne illness worldwide. In most cases, Salmonella contamination can be traced back to food processing plants and/or to cross-contamination during food preparation. To avoid food-borne diseases, food processing plants use sanitizers and biocidal to reduce bacterial contaminants below acceptable levels. Despite these preventive actions, Salmonella can survive and consequently affect human health. This study investigates the adaptive capacity of the main Salmonella enterica serotypes isolated from the poultry production line, focusing on their replication, antimicrobial resistance, and biofilm formation under stressors such as acidic conditions, oxidative environment, and high osmolarity. Using growth curve analysis, crystal violet staining, and microscopy, we assessed replication, biofilm formation, and antimicrobial resistance under acidic, oxidative, and osmotic stress conditions. Disinfectant tolerance was evaluated by determining the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of sodium hypochlorite. The antibiotic resistance was assessed using the Kirby–Bauer method. The results indicate that, in general, acidic and osmotic stress reduce the growth of Salmonella. However, no significant differences were observed specifically for serotypes Infantis, Heidelberg, and Corvallis. The S. Infantis isolates were the strongest biofilm producers and showed the highest prevalence of multidrug resistance (71%). Interestingly, S. Infantis forming biofilms required up to 8-fold higher concentrations of sodium hypochlorite for eradication. Furthermore, osmotic and oxidative stress significantly induced biofilm production in industrial S. Infantis isolates compared to a reference strain. Understanding how Salmonella responds to industrial stressors is vital for designing strategies to control the proliferation of these highly adapted, multi-resistant pathogens. Full article

Toothpaste is an essential oral hygiene product commonly used to sustain oral health due to its incorporation of antimicrobial agents. Numerous functional toothpastes enriched with antimicrobial agents have been developed and are available to consumers. This study evaluates the antimicrobial and antibiofilm efficacy of 12 commercially available toothpaste products, including those with specialized functions. Statistical significance was assessed to validate the differences observed among the toothpaste samples. Their effects on Streptococcus mutans, the primary pathogen responsible for dental caries, were evaluated. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined, and bacterial growth was measured to compare antimicrobial activities. Toothpaste containing 1000 μg/mL fluoride and whitening toothpaste exhibited the strongest antimicrobial effects, effectively inhibiting S. mutans growth. Additionally, bamboo salt-enriched and tartar-control toothpaste demonstrated inhibitory effects on bacterial growth. Assays to evaluate the ability of cells to form biofilms and the expression of genes involved in biofilm formation revealed a partial correlation between biofilm formation and spaP, gtfB, gtfC, and gtfD expression, although some showed opposite trends. Collectively, this study provides valuable insights into the antimicrobial and biofilm inhibition capabilities of commercial toothpastes against S. mutans, offering a foundation for evaluating the efficacy of functional toothpaste products. Full article

In recent years, most of the populations of the world have been using herbal materials for their strong antimicrobial properties and major health benefits. The objective of this study was to evaluate the phenolic profile, as well as the antioxidant and antimicrobial activities, of a dietary supplement composed of extracts from hibiscus (Hibiscus sabdariffa L.) calyces and lemon verbena (Lippia citriodora) leaves (Metabolaid^®, Patent P201731147) mixed at a weight ratio of 35:65 (w/w), respectively. The bioactive components of the methanolic extract were analyzed by UHPLC-ESI-MS/MS. The antioxidant activity was evaluated using spectrophotometric methods, while the antimicrobial activity was assessed through the microdilution method against selected Gram-negative and Gram-positive bacteria. The total phenols content resulted in being 256.10 ± 2.26 mg GAE/g f.w., the flavonoid content was 48.90 ± 2.95 mg CE/g f.w., flavonols were 60.17 ± 7.68 mg QE/g f.w., and anthocyanins were 3.78 ± 0.17 mg C3GE/g f.w. The FRAP value, observed in the natural mix additive, was 1.25 ± 0.03 mg Fe²⁺/g f.w., while the ORAC showed the value of 1893.77 ± 30.39 µmol TE/g f.w. and the DPPH was 23.33 ± 4.12 µg/mL. We found eight phenolic acids, seven flavonols, five anthocyanins, and nine other phenolic compounds. The extract showed a minimum inhibitory concentration (MIC) of 12.5 mg/mL against E. coli, E. aerogenes, and E. faecalis and of 25 mg/mL against S. enterica ser. Typhimurium and S. aureus and a minimum bactericidal concentration (MBC) of 25 mg/mL against E. coli, E. aerogenes, and E. faecalis and of 50 mg/mL against S. enterica ser. Typhimurium and S. aureus. In conclusion, our findings demonstrate that Metabolaid^® is a rich source of bioactive compounds and provides beneficial effects against oxidative stress and pathogenic bacteria, supporting its nutraceutical potential. Full article

Background/Objectives: The liver, the body’s primary detoxifying organ, is often affected by various inflammatory diseases, including hepatitis, cirrhosis, and non-alcoholic fatty liver disease (NAFLD), many of which can be exacerbated by secondary infections such as spontaneous bacterial peritonitis, bacteremia, and sepsis—particularly in patients with advanced liver dysfunction. The global rise in these conditions underscores the need for effective interventions. Natural products have attracted attention for their potential to support liver health, particularly through synergistic combinations of plant extracts. Epavin, a dietary supplement from Erbenobili S.r.l., formulated with plant extracts like Taraxacum officinale (L.), Silybum marianum (L.) Gaertn., and Cynara scolymus (L.), known for their liver-supporting properties, has been proposed as adjuvant for liver functions. The aim of this work was to evaluate of Epavin’s antioxidant, anti-inflammatory, and protective effects against heavy metal-induced toxicity. In addition, the antibacterial effect of Epavin against a panel of bacterial strains responsible for infections associated with liver injuries has been evaluated. Methods: The protection against oxidative stress induced by H₂O₂ was evaluated in HepG2 and BALB/3T3 cells using the dichlorofluorescein diacetate (DCFH-DA) assay. Its anti-inflammatory activity was investigated by measuring the reduction in nitric oxide (NO) production in LPS-stimulated RAW 264.7 macrophages using the Griess assay. Additionally, the cytoprotecting of Epavin against heavy metal-induced toxicity and oxidative stress were evaluated in HepG2 cells using the [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide] (MTT) and DCFH-DA assays. The antibacterial activity of Epavin was assessed by determining the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) against Gram-positive (Enterococcus faecalis ATCC 29212, and BS, Staphylococcus aureus 25923, 29213, 43300, and BS) and Gram-negative (Escherichia coli 25922, and BS, Klebsiella pneumoniae 13883, 70063, and BS) bacterial strains using the microdilution method in broth, following the Clinical and Laboratory Standards Institute’s (CLSI) guidelines. Results: Epavin effectively reduced oxidative stress in HepG2 and BALB/3T3 cells and decreased NO production in LPS-stimulated RAW 264.7 macrophages. Moreover, Epavin demonstrated a protective effect against heavy metal-induced toxicity and oxidative damage in HepG2 cells. Finally, it exhibited significant antibacterial activity against both Gram-positive and Gram-negative bacterial strains, with MIC values ranging from 1.5 to 6.0 mg/mL. Conclusions: The interesting results obtained suggest that Epavin may serve as a valuable natural adjuvant for liver health by enhancing detoxification processes, reducing inflammation, and exerting antibacterial effects that could be beneficial in the context of liver-associated infections. Full article

Infections caused by oxacillin-resistant Staphylococcus pseudintermedius are increasingly common in veterinary medicine. The indiscriminate use of antibiotics by pet owners worsens this problem, reducing treatment efficacy and creating the need for alternative therapies. This study aimed to evaluate the inhibitory effect of clove essential oil (Syzygium aromaticum) on both oxacillin-resistant and susceptible S. pseudintermedius. Thirty-five isolates from dogs with otitis externa were analyzed. The bacteria were identified by phenotypic tests and tested for susceptibility to 22 antibiotics using disk diffusion. Resistance genes (mecA and blaZ) were detected using conventional PCR. Among the isolates, 34.28% (12/35) were positive for mecA, and 97.14% (34/35) for blaZ. The essential oil’s efficacy was assessed using broth microdilution to determine its minimum inhibitory concentration (MIC). Clove oil showed an average MIC and minimum bactericidal concentration (MBC) of 6.4 mg/mL, inhibiting both resistant and susceptible isolates. In conclusion, clove essential oil demonstrated in vitro antimicrobial activity against S. pseudintermedius. Full article

The increasing demand for sustainable disease management in aquaculture has intensified interest in plant-based therapeutics. This study evaluated the formulation and efficacy of andrographolide-loaded nanostructured lipid carriers (AND-NLCs) in Nile tilapia (Oreochromis niloticus) challenged with Streptococcus agalactiae ENC06. AND-NLCs were prepared by the phase-inversion technique and characterized by dynamic light scattering, transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), and in vitro release profiling. Antibacterial activity was assessed by measuring inhibition zone diameters, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC). Growth performance, feed utilization, hepatosomatic index (HSI), and disease resistance were evaluated over a 60-day feeding trial. The AND-NLCs exhibited an optimal particle size (189.6 nm), high encapsulation efficiency (90.58%), sustained release, and structural stability. Compared to the free AND and control group, AND-NLC supplementation significantly improved growth, feed efficiency, HSI, and positive allometric growth. It also enhanced survival (73.3%) and relative percent survival (RPS = 65.6%) following S. agalactiae ENC06 infection. Antibacterial efficacy and physiological responses showed positive correlations with nanoparticle characteristics. These findings suggest that AND-NLCs enhance bioavailability and therapeutic efficacy, supporting their potential as a functional dietary additive to promote growth and improve disease resistance in tilapia aquaculture. Full article

This study focuses on the search for new effective synthetic antimicrobial compounds as a tool against the widespread presence of microorganisms resistant to existing drugs. Five derivatives of [1,3]thiazolo[3,2-b][1,2,4]triazoles were synthesized using an accessible protocol based on electrophilic heterocyclization and were characterized using infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies, and their in vitro antimicrobial and antifungal activities were evaluated using the agar plate diffusion method and the microdilution plate procedure. Both antibacterial (Gram-positive and Gram-negative) and antifungal activities were found for the examined samples. The minimum inhibitory concentration (MIC) varied from 0.97 to 250 µg/mL, and the minimum bactericidal concentration (MBC) from 1.95 to 500 µg/mL. Compound 2a showed good antifungal action against Candida albicans and Saccharomyces cerevisiae with minimum fungicidal concentration (MFC) 125 and MIC 31.25 µg/mL. The molecular docking revealed that the 2-heptyl-3-phenyl-6,6-trimethyl-5,6-dihydro-3H-[1,3]thiazolo[3,2-b][1,2,4]triazol-7-ium cation stands out as a highly promising candidate for further investigation due to a wide range of interactions, including conventional hydrogen bonds, π–σ, π–π T-shaped, and hydrophobic alkyl interactions. The synthesis and preliminary evaluation of [1,3]thiazolo[3,2-b][1,2,4]triazoles yielded promising antimicrobial and antifungal candidates. The diverse interaction profile of the 2-heptyl derivative salt allows this compound’s selection for further biological studies. Full article

Grass carp in aquaculture exhibited symptoms of bacterial infection leading to mortality. To investigate the cause of the disease and control grass carp infections, samples from diseased grass carp were collected, and a bacterial strain named XH-1 was isolated from the internal organs of the infected fish. Artificial infection experiments were conducted to determine whether the isolated strain XH-1 was the pathogenic bacterium. The biological characteristics of the isolated strain were studied through a 16S rRNA sequence analysis, physiological and biochemical identification, and phylogenetic tree construction. Extracts from 14 traditional Chinese herbs were tested to evaluate their bacteriostatic and bactericidal effects on the isolated strain. The regression infection experiment confirmed that the isolated strain XH-1 was the pathogenic bacterium causing the grass carp disease. Biological characterization studies identified the bacterium as Aeromonas veronii, which is clustered with A. veronii MW116767.1 on the phylogenetic tree. Among the 14 Chinese herbal extracts, Lignum sappa, Pericarpium granna, Artemisia argyi, Scutellaria baicalensis Georgi, Coptis chinensis, and Artemisiacapillaris thunb exhibited significant bacteriostatic effects on XH-1. Lignum sappa showed the highest sensitivity to A. veronii, with the largest inhibition zone diameter, and its minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were 7.813 mg/mL and 15.625 mg/mL, respectively. As the concentration of Lignum sappa extract increased, its bacteriostatic and bactericidal effects strengthened. When the concentration exceeded 14 mg/mL, it maintained strong bactericidal activity over 32 h. This study on A. veronii XH-1 provides theoretical insights for the prevention of grass carp aquaculture diseases and the use of traditional Chinese herbs for treatment. Full article

Background: The antimicrobial peptides (AMPs) SET-M33L and SET-M33L-PEG were investigated against 10 clinical isolates of P. aeruginosa. Methods: Their minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), and minimum biofilm inhibitory concentrations (MBICs) were evaluated against tobramycin, ceftazidime, and polymyxin B. Results: MICs and MBCs were 7- to 100-fold lower than tobramycin, and 10- to 300-fold lower than ceftazidime. Fractional inhibitory concentration (FIC) indices showed an additive effect, while fractional bactericidal concentration (FBC) indices showed synergistic effects (FBC < 0.5) for most isolates. Conclusion: SET-M33L and SET-M33L-PEG are promising antimicrobial agents against strong biofilm-forming P. aeruginosa, including MDR isolates. Full article

The green synthesis of zinc oxide nanoparticles (ZnO NPs) using Artemisia absinthium L. extract has gained considerable attention due to its eco-friendly approach and potential applications in food science. This study investigates the synthesis and characterization of Artemisia-mediated ZnO NPs, focusing on their physicochemical properties. The nanoparticles were characterized using ultraviolet–visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), and energy dispersive X-ray spectroscopy (EDX). Successful synthesis was achieved through a co-precipitation method, resulting in an average particle size of 36.6 nm. The presence of polyphenols and flavonoids in A. absinthium L. extract acted as both a reducing agent and stabilizer for the nanoparticles. The physicochemical characterization revealed strong absorption peaks indicative of ZnO, confirming successful nanoparticle formation. In addition to the structural findings, this study presents novel insights by demonstrating that Artemisia-mediated ZnO NPs possess significantly enhanced antimicrobial activity compared to both pure ZnO NPs and the plant extract alone. The biosynthesized nanoparticles exhibited notably lower minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC) values against Staphylococcus aureus, Escherichia coli, and Candida albicans, suggesting a strong synergistic effect between ZnO and the phytochemicals of A. absinthium L. Thus, the study confirms and quantifies the superior antibacterial potential of Artemisia-derived ZnO NPs, offering promising implications for food, biomedical and pharmaceutical applications. Full article

Green-synthesized metal nanoparticles show promise in nanomedicine and material engineering. In this study, the polysaccharide of Zingiber officinale (ZOP) was used as a raw material. Through single-factor experiments and a response surface methodology, the optimum synthesis protocol of Zingiber officinale polysaccharide silver nanoparticles (ZOP-NPs-AgNPs) was determined as follows: V(AgNO₃):V(ZOP) = 2.98:1, 59.79 °C, 3 h, pH 9, and 20 mL NaCl, achieving a 92.51% silver chelation rate. Structure analysis revealed that ZOP-NPs-AgNPs were spherical or quasi-spherical, with a particle size < 20 nm and a face-centered cubic crystal structure, which has good thermal stability. Subsequent studies explored the antibacterial and immunomodulatory effects of ZOP-NPs-AgNPs. The minimum inhibitory concentration (MIC) of ZOP-NPs-AgNPs against Escherichia coli and Staphylococcus aureus was determined to be 0.5000 mg/mL and 0.0310 mg/mL, respectively, while the minimum bactericidal concentration (MBC) was 0.5000 mg/mL and 0.0310 mg/mL, respectively. Additionally, ZOP-NPs-AgNPs significantly enhance RAW264.7 cell proliferation and phagocytosis and boost IL−1β, IL−6, NO, and TNF-α production. This confirms that ZOP can act as a green reductant and stabilizer, offering a new method for green nano-silver synthesis. This provides a sustainable way to produce antibacterial products and functional foods, and offers useful references for eco-friendly nano-silver applications. Full article

Crithmum maritimum L. is a halophyte with antioxidant and antimicrobial potential for the food industry. Pruning generates a by-product composed of woody stems, old leaves, and flowers. To valorize this underutilized and largely unexplored biomass, food-grade polar extraction (hydroethanolic vs. aqueous) was applied. The extracts were characterized for their bioactive compounds (polyphenols, tocopherols, carotenoids, total phenols (TPC) and total flavonoids (TFC)). Further, the extracts were assessed for their in vitro antioxidant activity (ABTS, DPPH, FRAP, and β-carotene bleaching) and antimicrobial activity against eight target strains ascribed to Escherichia coli, Staphylococcus aureus, and Listeria innocua. The hydroethanolic extract exhibited higher concentration of bioactives compared to the water extract and raw by-product. The β-carotene bleaching test revealed that both extracts are potent inhibitors of lipid peroxidation. The aqueous extract showed no antimicrobial activity, while the ethanolic extract exhibited strain-dependent behavior against S. aureus and L. innocua but not E. coli. The minimum inhibitory concentration and the minimum bactericidal concentration of the ethanolic extract against S. aureus were 2.5 MIC and 10.0 MBC mg/mL, respectively. Ethanolic extracts could potentially be used in food formulations to enhance lipid peroxidation resistance and antimicrobial capacity as food-grade natural preservatives. Full article

The increasing prevalence of antimicrobial resistance (AMR) demands novel strategies, including the use of plant-derived agents. This study investigates the chemical profile and in vitro antimicrobial activity of essential oil from Lavandula angustifolia (LEO), cultivated in Northeastern Bulgaria. Gas chromatography–mass spectrometry (GC-MS) analysis confirmed the presence of a linalool/linalyl acetate chemotype, characteristic of high-quality lavender oil. LEO demonstrated significant inhibitory activity against Escherichia coli ATCC 25922, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 0.31% (v/v) and moderate to weak activity against other Gram-positive and fungal strains. Time–kill assays revealed a concentration-dependent bactericidal effect on E. coli. The addition of LEO at subinhibitory concentrations increased the inhibition zones for all antibiotics. In silico analysis identified functional protein clusters potentially modulated by LEO constituents, including targets related to membrane integrity and metabolic regulation. The findings indicate the potential of lavender essential oil as a natural antimicrobial adjuvant; however, additional in vivo and clinical investigations are necessary to validate its therapeutic use. Furthermore, molecular docking analysis revealed a high binding affinity of linalool and linalyl acetate towards the FabI protein of E.coli, suggesting a potential inhibitory mechanism at the molecular level. Full article

Klebsiella pneumoniae can acquire resistance mechanisms to colistin and present a pan-resistant phenotype. Therefore, new alternative agents are imperative to control this pathogen, and the peptide Jelleine-I stands out as a promising prototype. Here, the antibacterial activity of Jelleine-I against clinical isolates of colistin-resistant K. pneumoniae (CRKP) was investigated. Antimicrobial activity was assessed by determining the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and time kill-curve assay. The release of 260 nm-absorbing materials (DNA/RNA) and the release of proteins were used in the lysis assay. Anti-biofilm activity was studied in microplates. In vivo activity was determined by the lethality assay using Tenebrio molitor larvae. The results show that the MIC of Jelleine-I ranged from 16 to 128 µM and the MBC was on average 128 µM. Jelleine-I at 200 µM killed all CRKP cells in suspension (10⁶ colony-forming units (CFU)/mL) after 150 min of incubation. Jelleine-I acts on the CRKP cell membrane inducing lysis. Biomass and viability of CRKP-induced biofilms are reduced after treatment with Jelleine-I, and the use of this peptide in T. molitor larvae infected with CRKP reduces lethality and improves overall larval health. In conclusion, Jelleine-I is a potential prototype for the development of new antimicrobial agents. Full article

Background/Objectives: Antimicrobial resistance (AMR) poses a significant global health challenge, contributing to foodborne infections and diminishing the effectiveness of conventional antibiotics. In the quest for alternative strategies to mitigate resistance, this study has assessed the potential of T. capitata L. (Cav.) essential oil (TEO) to boost the antibiotic efficacy on L. monocytogenes. Methods: Five L. monocytogenes strains of different origins were tested with TEO alone and in combination with gentamicin, ampicillin, and penicillin G. Moreover, the cells were exposed to sublethal concentrations of TEO for 1 h to evaluate the effects on the antibiotic effectiveness. The antimicrobial activity was assessed by determining the Minimum Inhibitory (MICs) and Bactericidal Concentrations (MBCs), while potential interactions were evaluated using the Fractional Inhibitory Concentration Index and by studying the cell growth dynamics. Results: TEO demonstrated inhibitory activity against L. monocytogenes strains, both alone, in pre-exposure, and in combination with antibiotics, causing up to a seven-fold reduction in MIC and MBC values (from 8 to 1 µg/mL) and restoring susceptibility to the antimicrobial treatments. Positive interactions between TEO and antibiotics were observed, particularly for clinical isolates. Conclusions: TEO could be a promising antibiotic adjuvant in antimicrobial treatments, offering a natural and effective strategy to enhance antibiotic efficacy and to counteract resistance in L. monocytogenes. Full article