Search Results (3,118)

Background: Dental caries is a biofilm-associated disease in which Streptococcus mutans plays a central role. This study evaluated HT-2-1-3, a Vespidae venom-derived antimicrobial peptide, as a potential topical anti-caries lead. Methods: Candidate peptides were synthesized by Fmoc solid-phase peptide synthesis and characterized by RP-HPLC and ESI-MS. Antibacterial activity against S. mutans UA159 was assessed using MIC, MBC, growth-curve, and time-kill assays. Membrane damage, antibiofilm activity, cytocompatibility, hemolysis, and preliminary oral safety in mice were further evaluated. Results: HT-2-1-3 showed the strongest activity among the tested peptides, with MIC and MBC values of 2 µg/mL. It inhibited bacterial growth in a concentration-dependent manner and achieved complete killing at 4×MIC (8 µg/mL) within 2 h. Mechanistic assays showed rapid membrane depolarization, increased PI uptake, and concentration-dependent release of extracellular DNA and proteins. MD simulations further indicated that HT-2-1-3 entered the model S. mutans UA159 membrane at 1857 ns, supporting membrane permeabilization as a central component of its bactericidal activity. Scanning electron microscopy revealed dose-dependent membrane disruption, cell collapse, and rupture. HT-2-1-3 inhibited biofilm formation by approximately 58–63% and eradicated up to 89.0% of mature biofilms. Hemolysis remained below 4% at concentrations up to 64×MIC (128 µg/mL), and mammalian-cell viability exceeded 95% at concentrations up to 16×MIC (32 µg/mL). Repeated oral administration caused no obvious gingival irritation in mice. Conclusions: HT-2-1-3 showed strong bactericidal and antibiofilm activity against S. mutans UA159 and favorable preliminary biocompatibility. Its mode of action may involve membrane disruption, and it showed favorable preliminary biosafety. These findings support further optimization of HT-2-1-3 as a topical antimicrobial candidate for caries prevention and control. Full article

The increasing prevalence of biofilm-associated infections caused by Cutibacterium acnes has stimulated interest in food-derived natural products as alternative sources of anti-biofilm agents. This study investigated the effects of processing and extraction conditions on the phytochemical composition, antibacterial activity, and anti-biofilm properties of Dioscorea hispida Dennst. Reflux extraction of dried yam with 80% ethanol produced the crude extracts with the highest yields (1.39–1.80%), whereas fresh yam yielded 0.51–0.97% extract. Using Gas–liquid chromatography–mass spectrometry (GLC-MS) analysis, linoleic acid ethyl ester, n-hexadecanoic acid, 9,12-octadecadienoic acid (Z,Z)-, and stigmasterol were identified as the major constituents. Among the tested extracts, DH-W-F-H (D. hispida-water washing-fresh-hexane) and DH-W-F-E (D. hispida-water washing-fresh-ethanol) were extracted from fresh yam using hexane and ethanol, respectively, while DH-W-D-E (D. hispida-water washing-dry-ethanol) was isolated from dried yam using ethanol and exhibited the strongest antibacterial activity, with minimum inhibitory concentrations (MIC) ranging from 64 to 2048 µg/mL. These extracts demonstrated pronounced concentration-dependent inhibition of biofilm formation by Staphylococcus epidermidis, Staphylococcus aureus, and Cutibacterium acnes. The strongest anti-biofilm activity was observed against C. acnes, with biofilm formation nearly eliminated at MIC concentrations. Moreover, all three extracts significantly reduced established C. acnes biofilms, with DH-W-F-H exhibiting greater eradication efficacy than vancomycin under the tested conditions. To elucidate the underlying mechanism, major fatty acid derivatives were evaluated against C. acnes lipase (_CALipase), a virulence factor associated with biofilm development, using molecular docking, molecular dynamics simulations, and the Molecular Mechanics-Generalized Born Surface Area (MM-GBSA) binding free-energy calculations. The compounds exhibited favorable interactions with _CALipase, with linoleic acid ethyl ester (FA2) showing the strongest binding affinity, stable protein–ligand interactions throughout a 200 ns simulation, and the most favorable binding free energy. Collectively, the biological and computational findings suggest that fatty acid-rich extracts from processed D. hispida suppress biofilm formation through an antivirulence mechanism involving _CALipase inhibition. These results highlight the potential of D. hispida as a source of metabolites for the development of functional food ingredients and value-added cosmetic and dermatological applications. Full article

Objectives: The study determined antimicrobial resistance profiles of surgical wound multidrug-resistant (MDR) isolates belonging to the ESKAPE group and evaluated antibacterial and antibiofilm activities of geraniol (G), carvacrol (C) and eugenol (E), individually and in the selected mixtures. The cytotoxicity of monoterpenes and combinations was also assessed. Methods: The antibacterial and antibiofilm activity against tested isolates of Enterococcus faecium, Staphylococcus aureus MRSA, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter sp. was assessed in microdilution and crystal violet assay, respectively, while cytotoxicity was estimated in XTT assay on human MRC-5 fibroblasts. Results: C showed the strongest antibacterial activity (MIC 0.32 ± 0.24 mg mL⁻¹). Monoterpenes induced synergism in certain combinations (FICI 0.09–0.31). All individual monoterpenes inhibited biofilm formation, but G was the most active (38.78–84.72%, p < 0.05). The most pronounced biofilm eradication was observed for C (25.21–61.34%, p < 0.05). G-C mixtures showed notable inhibition of biofilm formation in all isolates except P. aeruginosa, but, on the contrary, induced biofilm eradication against P. aeruginosa only. Cytotoxicity was not detected with the applied concentrations of monoterpenes, while the G-C mixtures exhibited lower cytotoxicity than povidone-iodine (p < 0.05) used as the control. Conclusions: All monoterpenes and G-C mixtures proved significant antibacterial and antibiofilm potential against ESKAPE isolates and acceptable impact on cell viability. Practical significance: The results highlight the potential of plant monoterpenes and their binary combinations as complementary agents for controlling MDR ESKAPE pathogens and biofilm-associated infections following surgical procedures. Further in vivo and safety studies are needed to confirm their applicability in clinical settings. Full article

Background/Objectives: Pseudomonas aeruginosa is an opportunistic Gram-negative bacterium and a major cause of healthcare-associated infections worldwide, exhibiting intrinsic antimicrobial resistance and readily acquiring novel resistance mechanisms. Divalent cations such as Mg²⁺ and Ca²⁺ in the culture environment can influence bacterial antibiotic susceptibility. This study evaluated the impact of varying concentrations of Mg²⁺ and Ca²⁺ on the antibiotic susceptibility of P. aeruginosa to tobramycin and ciprofloxacin under both planktonic and biofilm growth modes. Methods: The study determined the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum biofilm eradication concentration (MBEC) to compare alterations in antibiotic susceptibility across different ion conditions and bacterial growth patterns. Results: Our findings suggest that elevated concentrations of Mg²⁺ and Ca²⁺ significantly modulate bacterial antibiotic susceptibility. Conclusions: The results of our study has implications for limitations in standardised antibiotic susceptibility tests and to therapeutic strategies in cation-rich environments such as cystic fibrosis airways. Full article

Propolis is a resinous natural product collected by bees from plant sources to protect the hive. Its chemical composition varies according to bee species and environmental conditions, resulting in differences in its biological activities. This study aimed to evaluate the biological properties of stingless bee propolis collected from different provinces in Thailand, with particular attention to two native species, Tetragonula pegdeni and Tetragonula laeviceps. These two species of Tetragonula are commonly found in tropical regions of the country. The investigation focused on their antioxidant, antimicrobial, and anti-inflammatory activities. The propolis extract from T. laeviceps stingless bee (sample D) exhibited the highest total phenolic and flavonoid contents, at 29.59 mg GAE/g extract and 73.95 mg QUE/g extract, respectively. Among the propolis extracts, T. pegdeni stingless bee propolis extract (sample A) showed the greatest antioxidant activity of 7.08 ± 0.18 GAE/g extract and 75.64 ± 3.07 mg TEAC/g extract by the DPPH and ABTS assays, respectively, together with the highest FRAP value of 48.54 ± 0.48 mg FeSO₄/g extract. The antibacterial efficacy of these extracts was further evaluated against skin pathogenic bacteria, including Staphylococcus aureus, Staphylococcus epidermidis, methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, Micrococcus luteus, and Cutibacterium acnes. Inhibition zones ranged from 7.00 to 14.00 mm when determined by the agar disc diffusion method. Moreover, antibacterial activity was investigated by broth dilution assay, and MIC and MBC values ranged from 0.97 to 125 mg/mL. The cytotoxicity test of propolis extracts using RAW264.7 macrophage cells showed cell viability above 70%, and the selected concentrations were used for further anti-inflammatory evaluation. T. pegdeni stingless bee propolis extracts (samples A and B) demonstrated anti-inflammatory activity by reducing NO production and decreasing the expression of iNOS, COX-2, and IL-1β genes in LPS-stimulated RAW264.7 macrophage cells. LC–MS analysis revealed differences in chemical profiles among the propolis extracts and various bioactive compounds, including phenolic acids, flavonoids, xanthones, terpenoids, triterpenoids, and curcuminoids were identified. Therefore, Thai stingless bee propolis demonstrated potential as a natural source of bioactive compounds with antioxidant, antibacterial, and anti-inflammatory properties. Full article

The composition of honey is complex and can vary depending on its botanical and geographical origin. This study evaluated the phenolic acid profile (PAP), antioxidant activity, and antimicrobial properties of honey samples from different geographical origins, such as Romania (nine types: multiflower, thyme, manna, hawthorn, black locust, linden, rapeseed, mint, and pasture), Malaysia (Tualang), New Zealand (Manuka), and Spain (chestnut). Twelve different varieties of honey were analyzed, one sample for each type, and all analyses were performed in triplicate. Phenolic acids were extracted by solid-phase extraction (SPE) using C18 cartridges, followed by high-performance liquid chromatography with diode-array detection (HPLC-DAD) analysis at 310 nm. Antioxidant activity was assessed using the 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. Antimicrobial activity was evaluated by agar diffusion and broth microdilution to determine the minimum inhibitory concentration (MIC), while microbial anti-adherence activity was assessed using the crystal violet staining assay to determine the minimum anti-adherence inhibitory concentration (MAIC). The tested microorganisms included the reference strains Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212, and Candida albicans ATCC 10231, as well as two C. albicans isolates (24114 and 5329). Several phenolic acids, including chlorogenic, caffeic, ferulic, trans-cinnamic, 3-O-methylgallic, p-coumaric, and syringic acids, were identified at varying concentrations across the analyzed honey samples. Rapeseed honey exhibited the highest overall concentration of phenolic acids. Among the honey samples analyzed, chestnut honey had the highest concentration of cinnamic acid, mint honey the highest concentration of ferulic acid, and multiflower honey the highest concentration of syringic acid. Tualang honey exhibited the highest antioxidant activity by both methods, reaching 2.103 mg TE/g honey for DPPH and 1.701 mg TE/g honey for ABTS. Tualang honey also exhibited the strongest antimicrobial activity against C. albicans and P. aeruginosa, whereas multifloral honey was the most active against E. faecalis. The analyzed honey extracts differed in their phenolic acid composition and biological activities, including antioxidant, antimicrobial, and anti-adherence effects of microorganisms on substrates. While associations were observed between selected phenolic acids and some of the evaluated biological activities, the overall biological properties of honey are more likely to arise from the combined contribution of multiple bioactive constituents than from individual compounds alone. The novelty of this study lies in the comparative assessment of the PAP obtained following SPE, and the biological activities of different types of honey from various botanical and geographical sources. Full article

Microbial contamination remains a major challenge in food systems, creating demand for stable natural antimicrobials. This study investigates the inducible antibacterial response of Hermetia illucens and characterized the black soldier fly defensin-like peptide DLP4. Larvae were challenged with Staphylococcus aureus or Escherichia coli, and hemolymph activity, antimicrobial-peptide gene expression, C18 solid-phase extraction fractions, and LC–MS/MS profiles were evaluated. Synthetic mature DLP4 was further assessed for antibacterial spectrum, physicochemical stability, and structural properties. Hemolymph antibacterial activity varied with treatment and time, while DLP4 and CLP1 showed distinct transcriptional responses. Antibacterial activity was concentrated in early fractions, with F3 showing the greatest activity. LC–MS/MS detected a conserved DLP-family motif and a cysteine-rich defensin-like peptide in F3, whereas the complete 40-amino-acid sequence of synthetic DLP4 was confirmed. DLP4 showed strong, strain-dependent activity against Gram-positive bacteria, including Bacillus subtilis, Listeria ivanovii, and Staphylococcus spp., while no MIC endpoint was detected for the tested E. coli strains. DLP4 retained substantial activity after heat, ultraviolet, storage, pH, NaCl, and most metal-ion treatments, although Fe³⁺ reduced activity. These findings support DLP4 as a stable, Gram-positive-active antimicrobial candidate for further evaluation in food systems. Full article

Antibiotic resistance of microorganisms threatens global health and agriculture. Antimicrobial peptides can display broad-spectrum activity, making them candidate alternatives to antibiotics. Here, ten antimicrobial peptides were tested against fungal pathogens, including Candida albicans, Cryptococcus neoformans, Aspergillus niger, and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) pathogens. Aurein 1.2, halictine-II, and macropin-I showed broad-spectrum activity. In particular, halictine-II showed high potency combined with low hemolytic activity, with the MIC values across species being 5 to 90-fold lower than the observed hemolytic concentration. Full article

Geographical and botanical origin dominate the chemical composition and biological activity of propolis samples. In this study, thirty Turkish propolis samples collected from different regions within the Black Sea region were comprehensively evaluated to investigate the relationships between phytochemical composition, antioxidant capacity, antibacterial activity, and anticancer potential. The propolis samples were extracted using 70% aqueous ethanol and labeled as K1-K30. Total phenolic content (TPC), total flavonoid content (TFC), ferric reducing antioxidant power (FRAP), and DPPH radical scavenging activity were determined. Antibacterial activity was evaluated against both Gram-positive and Gram-negative bacterial strains using inhibition zone (ZI), minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) tests. Most of the extracts showed measurable antibacterial activity, where Gram-positive bacteria generally showed higher susceptibility compared to the tested Gram-negative bacterial species. The extracts K12, K13, K22, K24, and K28 demonstrated the strongest broad-spectrum antibacterial activity. Pearson correlation analysis revealed that antibacterial efficacy was more strongly associated with antioxidant capacity and flavonoid richness than with total phenolic content alone. FRAP and TFC emerged as the strongest predictors of antibacterial activity, while specific phenolic compounds (particularly quercetin and trans ferulic acid) were associated with enhanced activity against Gram-negative bacteria. Preliminary anticancer activity was assessed using cell viability assays at 24, 48, and 72 h. Cytotoxic responses were highly heterogeneous and strongly time-dependent. K10, among the extracts, exhibited the strongest anticancer activity, showing inhibition rates above 80% at 24 and 48 h, whereas K4 and K23 also demonstrated considerable cytotoxic effects. Notably, antibacterial and anticancer activities were not directly correlated. Extracts with strong antibacterial activity, such as K12 and K22, showed proliferative effects in anticancer assays, whereas K10 displayed weak antibacterial but strong anticancer activity. These findings demonstrate that antibacterial and anticancer properties of propolis are governed by distinct phytochemical compositions. Overall, this study highlights the multidimensional bioactivity of Turkish propolis and emphasizes the importance of comprehensive phytochemical characterization for identifying extracts with application-specific therapeutic potential. Full article

Background/Objectives: Acinetobacter baumannii is a multidrug-resistant (MDR) nosocomial pathogen associated with significant morbidity and mortality. The emergence of strains resistant to multiple antibiotics has markedly reduced available treatment options. A. baumannii now demonstrates resistance to most first-line antibiotics, resulting in the extensive use of colistin, which in turn has led to the emergence of colistin-resistant strains. There are very limited studies from India on the mechanisms of colistin resistance. In this study, we focused on the molecular mechanisms leading to colistin resistance. Methods: A total of 225 clinical isolates of Acinetobacter baumannii were analyzed in this study. Antimicrobial susceptibility testing was done using the disk diffusion method for various classes of antimicrobial agents as per the Clinical Laboratory Standards Institute (CLSI M100 Ed 35,2025). Susceptibility to colistin was tested by the Microbroth dilution method. Colistin resistance mediated by the mcr gene and alterations in the pmrAB and lpxACD genes were investigated using conventional PCR followed by mutational analysis. Results: Among the 225 isolates, 4 isolates were found to be colistin resistant. All the resistant isolates had an MIC ≥ 16 mcg/mL. Mutations were found in lpxA and pmrB (c.391T > C, c.495T > C, c.516A > G, c.732A > G and c.966T > C). Mutations in pmrA, lpxC, and lpxD were not detected in this study. Mcr-1 gene was not detected in this study. Conclusions: Colistin is the last resort for the treatment of MDR strains, and the increase in resistance to colistin has become a huge concern among the medical community as it reduces the options available for treatment. This is the first report on the molecular mechanisms of colistin resistance in South India using PCR. The study is also the first to report four novel mutations in the genes that may be responsible for resistance. Early detection of resistance and swift control measures can help curb the morbidity and mortality rate among such A. baumannii strains. Full article

Background: Enterococcus species have emerged as significant multidrug-resistant nosocomial pathogens. Linezolid remains a vital last-resort therapeutic option for the management of severe infections caused by vancomycin-resistant Enterococci. However, resistance to linezolid occurs through several mechanisms, including the presence of the cfr, cfr(D), and optrA genes, as well as mutations in domain V region of the 23S ribosomal RNA gene. This study aimed to detect and characterize linezolid resistance in clinical Enterococcus species. Methodology: A total of 266 clinical isolates belonging to the Enterococcus species were analyzed in this study. Antimicrobial susceptibility testing was performed using the disc diffusion method. The Minimum Inhibitory Concentration (MIC) of linezolid was determined by the agar dilution technique. PCR was performed to detect the presence of cfr, cfr(D), and optrA genes, along with mutations in domain V of the 23S rRNA gene. Results: Among the 266 isolates analyzed, 25 (9.4%) were found to be resistant to linezolid, with MIC values ≥ 8 µg/mL. Of these resistant isolates, the cfr gene was detected in one isolate, cfr(D) in sixteen isolates, and optrA in nine isolates. Notably, four isolates carried mutations in the domain V region of the 23S rRNA gene, including a novel C2626T mutation (in India) along with the previously reported G2592T mutation. Conclusions: This study reports the detection of cfr- and cfr(D)-mediated linezolid resistance among Enterococcus species in India. Furthermore, the presence of optrA and a novel C2626T mutation, alongside the G2592T mutation, was identified among resistant isolates. These findings underscore the urgent need for molecular surveillance to prevent further dissemination of these multidrug-resistant pathogens. Full article

Background/Objectives: Colibacillosis, caused by enteropathogenic strains of Escherichia coli (EPEC), is one of the most common infectious diseases in rabbit farms. In the past, antimicrobials were widely used to control colibacillosis, but their use in prevention is currently prohibited. Therefore, the adoption of new prevention strategies as alternatives to the use of antibiotics is very important. The aim of this study was to evaluate the antimicrobial efficacy of cinnamon essential oil (Cinnamomum zeylanicum) against EPEC strains responsible for colibacillosis in rabbits. Methods: For the experiment, 124 strains of E. coli isolated from rabbits that had died of colibacillosis in 10 industrial farms were used. Suspensions of each strain prepared according to CLSI standards with a bacterial density of 1 × 10⁸ CFU/mL were tested using 100% pure commercial cinnamon essential oil (CEO) at concentrations ranging from 0.2 to 0.8 μL/mL. Minimum inhibitory concentrations MIC₅₀ and MIC₉₀ were determined according to a protocol described previously. Results: MIC₅₀ and MIC₉₀ were 0.5 μL/mL and 0.6 μL/mL, inhibiting 64.5% and 94.3% of strains, respectively. Furthermore, strains exposed to 0.4 μL/mL were 12.9 times more likely to be inhibited than those exposed to 0.3 μL/mL (p = 0.0001). Conclusions: CEO was found to be effective against E. coli strains tested at high bacterial densities that can usually be found per gram of faeces in rabbits affected by colibacillosis. Consequently, cinnamon should be useful in preventing colibacillosis by limiting the replication of E. coli, as it is usually found in lower densities in the intestines of healthy rabbits, preventing the onset of colibacillosis and reducing the use of antibiotics in rabbit farms. Full article

Conventional lysozyme–chitosan (LCS) coatings combine the film-forming properties of chitosan with lysozyme-mediated antibacterial activity, but their antioxidant capacity and activity against Gram-negative bacteria remain limited. In this study, purified lotus leaf flavonoids (LLF) were incorporated into a LCS matrix at 0.1–0.3% (w/v) to examine how a defined flavonoid fraction affects matrix structure, film performance, and strawberry preservation under ambient storage. LLF showed strong radical-scavenging activity, with IC₅₀ values of 6.244 µg/mL for DPPH and 2.146 µg/mL for ABTS, and inhibited Staphylococcus aureus and Escherichia coli (MIC values of 0.625 and 1.25 mg/mL, respectively). Structural analyses indicated concentration-dependent, predominantly non-covalent interactions between LLF and the LCS network. LLF addition increased color intensity and opacity and altered water-related, barrier, thermal, and mechanical properties, revealing a formulation trade-off rather than uniform improvement of all material attributes. The LLF-LCS systems nevertheless showed stronger antioxidant and in vitro antibacterial activities than the CS and LCS controls. During 6 d of storage at 25 ± 2 °C, 0.2–0.3% LLF-LCS treatments reduced decay, limited weight loss, retained firmness, and better-preserved ascorbic acid, total phenolics, and anthocyanins. These findings demonstrate a formulation-dependent structure–property–preservation relationship for purified LLF in LCS coatings under short-term ambient storage and identify 0.2% LLF as the most balanced formulation within the tested range. Full article

Medicinal plants in the Acanthaceae family have long been used in Thai traditional medicine. In this study, ethanolic extracts of four plant species, Andrographis paniculata, Thunbergia laurifolia, Acanthus ebracteatus, and Rhinacanthus nasutus, were prepared and their phytochemical and pharmacological properties were evaluated. Total phenolic and flavonoid content assays were used to investigate phytochemical content and phytochemical profiles were characterized with LC-MS, while antioxidant activities were assessed via colorimetric methods. The extracts were also tested for antibacterial activity against several skin pathogens, such as Pseudomonas aeruginosa, Cutibacterium acnes, Micrococcus luteus, Staphylococcus aureus, and methicillin-resistant S. aureus, using agar well diffusion and broth dilution methods. Cytotoxic effects on the RAW 264.7 macrophage cell were assessed using the MTT assay. The extracts were further evaluated for anti-inflammatory activity in an LPS-stimulated RAW 264.7 cell. Inflammatory gene expression was assessed by quantifying the mRNA levels of iNOS, COX-2, TNF-α, IL-1β, IL-6, and NF-κB genes using RT-qPCR. The results revealed that among the four species, T. laurifolia extract showed the highest phenolic and flavonoid levels, consistent with the greatest antioxidant activity. Moreover, LC-MS profiling annotated a range of secondary metabolites in the extracts. The inhibition zones were observed for all plant extracts when tested against the skin pathogenic bacteria except C. acnes, and A. paniculata did not inhibit P. aeruginosa, indicating the antibacterial activity of the extracts. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values differed across the extracts and bacterial strains. T. laurifolia exhibited the most potent activity against various bacterial pathogens, while A. paniculata was most effective against C. acnes at 0.98 mg/mL. In addition, all plant extracts reduced nitric oxide production and downregulated the expression of inflammatory genes. Among all plant species, A. paniculata showed the most potent activity with the highest NO inhibition of 65.68% at 60 µg/mL. Therefore, these findings support the antioxidant, antibacterial, and anti-inflammatory potential of A. paniculata, T. laurifolia, A. ebracteatus and R. nasutus, which are traditionally used in folk medicine. Full article

The occurrence of multidrug-resistant (MDR) bacteria in foods of animal origin is a public health concern that underscores the need to investigate natural antimicrobial alternatives. Although Syzygium aromaticum essential oil exhibits antibacterial activity, evidence regarding its bactericidal effects against MDR bacteria recovered from commercial eggs remains limited. This study evaluated the bactericidal activity of eugenol-rich S. aromaticum essential oil (SAEO) and explored its potential antibacterial mechanisms. SAEO was obtained by steam distillation and chemically characterized by gas chromatography–mass spectrometry (GC–MS). Its antibacterial activity was evaluated by determining the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), bacterial growth kinetics, and changes in membrane permeability. Molecular docking was performed to examine the interactions of eugenol with dihydropteroate synthase (DHPS) and β-ketoacyl-acyl carrier protein synthase III (FabH). Eugenol was the predominant constituent (73.9%), followed by dihydroeugenyl acetate (14.1%) and β-caryophyllene (6.0%). SAEO exhibited bactericidal activity against all tested strains, with MIC and MBC values ranging from 0.125 to 0.25 mg/mL and from 0.25 to 0.50 mg/mL, respectively. SAEO also produced sustained bacterial growth inhibition and concentration-associated changes in membrane permeability. Molecular docking predicted favorable interactions of eugenol with DHPS and FabH; however, these interactions require experimental validation. Overall, the findings demonstrate the in vitro bactericidal activity of eugenol-rich SAEO against MDR bacteria recovered from commercial eggs and support further investigation of its potential application in food-safety interventions. Full article