Search Results (2,307)

This in vitro study compared the antimicrobial and antibiofilm efficacy of four commercially available chlorhexidine (CHX)-based mouthwashes, with different nominal CHX concentrations, against clinically relevant postoperative oral pathogens, including Staphylococcus aureus, Streptococcus mutans, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, and Candida auris. Antimicrobial potency was evaluated using MIC and CEMIC indices, while biofilm thickness reduction was quantified using 3D digital microscopy and custom image analysis software. Among the tested formulations, the excipient-enriched formulation exhibited the lowest MIC values and the most significant reduction in biofilm thickness, particularly against Gram-negative bacteria and Candida species. All mouthwashes achieved CEMIC < 0.1, confirming high theoretical applicability margins; however, CEMIC reflects potential clinical usefulness rather than clinical superiority. The findings demonstrate that the antimicrobial and antibiofilm activity of CHX rinses is formulation-dependent and cannot be predicted solely by CHX concentration. The influence of excipients is discussed as a possible contributing factor, but related mechanisms remain speculative and require direct validation in future studies. This work supports a formulation-driven, evidence-based approach to antiseptic comparison in postoperative dentistry, without assessing clinical wound-healing outcomes. Full article

The valorization of agri-food residues is crucial for advancing circular bioeconomy strategies and mitigating environmental impacts. Turnip greens (Brassica rapa subsp. sylvestris) are a traditional vegetable cultivated in southern Italy. While the edible portions include flower sprouts, buds, and young leaves, the more leathery leaves and stems are typically discarded. These wastes represent valuable sources of compounds with antioxidant and antimicrobial potential. This study aims to develop the extraction of phenolic compounds from turnip green residues using two techniques: silent maceration and ultrasound-assisted extraction (UAE). Ethanol was selected over methanol as a food-safe alternative solvent, with preliminary tests confirming equivalent efficiency. A Design of Experiments (DoE) approach was applied to both leaves and stems to assess the effects of solvent composition, solvent-to-matrix ratio, and extraction time on Total Phenolic Content and Trolox Equivalent Antioxidant Capacity. DoE results identified UAE as the most effective method for stems, while for leaves, the solvent-to-dry-mass ratio was the key parameter. HPLC-DAD analysis was performed to identify and quantify the phenolic acids in selected extracts. The antibacterial activity of these extracts against biofilms of six pathogenic strains was evaluated using crystal violet and MTT assays, confirming efficacy in both biofilm formation and mature stages. Full article

Due to the limitations of conventional antibiotics, antimicrobial peptides (AMPs) have emerged as promising therapeutic alternatives for the prevention and treatment of oral infections. This study systematically evaluated in vitro evidence regarding the antimicrobial and anti-biofilm activity of natural AMPs against oral pathogens. A systematic search using the PICOT strategy was conducted in PubMed, EMBASE, and Scopus, retrieving 7711 articles. After title and abstract screening, 109 studies were selected for full-text analysis, resulting in 26 articles that met the eligibility criteria. Among the AMPs evaluated, nisin (n = 15) and LL-37 (n = 5) were the most frequently investigated, while other peptides included lactoferrin, lactoferricin, melittin, lysozyme, histatin-5, cystatin C, chromogranin A, parasin-1, protamine, AmyI-1-18, and DCD-1L. Natural AMPs of human and animal origin demonstrated antimicrobial activity against bacteria associated with oral infections, particularly Streptococcus mutans and Enterococcus faecalis. These peptides were tested in different formulations, including solutions, incorporation into dental materials and polymers, and application in sonodynamic antimicrobial therapy. Overall, the findings indicate that natural AMPs represent a promising class of biomolecules for controlling oral biofilms; however, further clinical studies are required to validate their long-term efficacy and safety. Full article

Dental caries is a major global health issue associated with biofilm formation by Streptococcus mutans (S. mutans). Conventional antimicrobials often fail to eliminate biofilms due to their structural resistance, highlighting the need for new strategies. This study investigated the antibacterial and antibiofilm effects of protamine peptides (PPs), which are cell-penetrating antimicrobial peptides derived from salmon protamine, alone and in combination with antimicrobial agents. Antimicrobial susceptibility was evaluated using alamarBlue^® and colony count assays, while biofilm formation was analyzed using crystal violet staining, confocal microscopy, and extracellular polysaccharide (EPS) quantification. PP exhibited moderate antibacterial activity but strongly suppressed EPS accumulation and biofilm development, leading to a flattened biofilm structure. Cotreatment with ε-poly-L-lysine (PL) significantly enhanced antibacterial and antibiofilm effects compared with either agent alone, whereas this effect was not observed with other cationic polymers. Fluorescence imaging revealed that PL promoted the intracellular localization of PP without increasing membrane damage, indicating a cooperative mechanism by which PL enhances membrane permeability and PP targets intracellular sites. These findings demonstrate that combining a cell-penetrating peptide with a membrane-active agent is a novel approach to overcome bacterial tolerance. The PP–PL combination effectively suppressed S. mutans growth and biofilm formation through dual action on membranes and EPS metabolism, offering a promising basis for the development of peptide-based preventive agents and biofilm-resistant dental materials. Full article

The rise of multidrug-resistant tuberculosis (TB) necessitates alternative therapeutic sources. This study investigated the polyphenolic content and the antioxidant, antimycobacterial, and anti-virulence activities of selected medicinal plants traditionally used to treat TB and related symptoms. Total phenolics, tannins, and flavonoids were quantified using colorimetric assays. Antioxidant capacity was assessed via DPPH and ferric-reducing power assays. Antimycobacterial activity against Mycobacterium smegmatis was evaluated using broth microdilution, growth kinetics, cell constituent leakage, and respiratory chain dehydrogenase inhibition assays. Anti-virulence effects were examined using crystal violet biofilm and swarming motility assays. Tarchonanthus camphoratus showed the highest polyphenolic levels and, together with Combretum hereroense, strong antioxidant activity. Extracts of Senecio macroglossus, Nerium oleander, and Tetradenia riparia displayed potent antimycobacterial activity (MIC = 0.16 mg/mL), characterized by delayed exponential growth, membrane damage, and metabolic inhibition. Tabernaemontana elegans exhibited the weakest activity (MIC > 2.5 mg/mL). Most extracts also significantly impaired motility (12–100%) and early-stage biofilm formation. Polyphenolic-rich plant extracts demonstrated promising antimycobacterial and anti-virulence properties against M. smegmatis, highlighting their potential as leads for developing novel anti-TB agents. Full article

The threats leading to the extinction of humanity accelerate the evolution and development of materials that are capable of providing conditions for preserving health and, implicitly, life. In our work, we developed drug delivery systems based on mesoporous silica which can deliver an antibiotic, bacitracin, in a more controlled manner. The synthesis of the FDU-12 was performed through a sol–gel method and alternatively functionalized with -NH₂ groups or with poly(N-acryloylmorpholine) chains. The loading of bacitracin was performed using the vacuum-assisted method we successfully used to load these mesoporous materials preferentially within the pores as proved by the TGA-DSC results. The release was performed in two types of simulated body fluid (SBF) and this process was evaluated with chromatographic method using UV detection. The obtained data were fitted in three mathematical models of kinetic drug release (Weibull model, Korsmeyer–Peppas model, and nonlinear regression). The antimicrobial evaluation demonstrated that bacitracin-loaded FDU-12 formulations exhibited strong activity against both reference and clinical Staphylococcus strains. At sub-inhibitory concentrations, all formulations significantly reduced microbial adherence and biofilm formation, although certain strain-dependent stimulatory effects were observed. Furthermore, exposure to sub-MIC levels modulated the production of soluble virulence factors (hemolysins, lipase, and amylase), in a formulation- and strain-dependent manner, underscoring the ability of surface-functionalized FDU-12 carriers to influence bacterial pathogenicity while enhancing antimicrobial efficacy. Full article

Bacterial infections remain a major challenge to human health, especially in wound healing, where they can cause prolonged inflammation, delayed recovery, and severe complications. Current research is increasingly focused on developing innovative antimicrobial materials capable of overcoming the limitations of conventional antibiotics, whose effectiveness has declined due to the rise in bacterial resistance. Among the various alternatives, silver nanoparticles have gained particular attention for their broad-spectrum antibacterial properties and have already been successfully applied in the functionalization of commercial wound dressings. The aim of this study was to optimize the functionalization of commercial cotton gauzes based on in situ UV-assisted reduction of silver nanoparticles, reducing methanol usage and identifying the minimal silver nitrate precursor concentration to achieve antimicrobial efficacy while maintaining biocompatibility. Different precursor concentrations were then evaluated through cytocompatibility assays (MTT, Live/Dead, and scratch tests on fibroblasts) and antimicrobial analyses against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus (including an antibiotic-resistant strain), and Candida albicans. The results demonstrated that a 0.5% w/w silver nitrate concentration provided strong antimicrobial and antibiofilm activity without compromising textile properties or cytocompatibility. Furthermore, this optimized process reduced material waste, highlighting its potential for scalable production of antimicrobial wound dressings. Full article

The intensification of aquaculture practices has been accompanied by an increased incidence of bacterial diseases, leading to a greater reliance on antibiotics for disease control. Consequently, the widespread and often indiscriminate use of these compounds has contributed to the emergence and dissemination of antibiotic-resistant bacteria within aquaculture systems, posing a serious threat to animal health, environmental sustainability, and public health. In this regard, research efforts have focused on developing alternative strategies to reduce antibiotic use. Natural compounds have gained particular attention due to their well-documented antimicrobial and antibiofilm activities. In this context, the combined application of antibiotics and natural compounds has emerged as a promising approach to enhance antimicrobial efficacy while potentially mitigating the development of resistance. This review synthesizes the current knowledge on antibiotic resistance in aquaculture, highlights the role of biofilm formation as a key resistance mechanism, and critically examines the potential of antibiotic–natural compound combinations against major aquaculture pathogens, with particular emphasis on bacterial growth inhibition, biofilm disruption, and virulence attenuation. Collectively, the evidence discussed underscores the potential of synergistic strategies as a sustainable tool for improving disease management in aquaculture while supporting efforts to limit antibiotic resistance. Full article

Dental caries is a multifactorial chronic infectious disease that impacts healthcare costs globally, caused by alterations of the plaque microbiome and proliferation of cariogenic Streptococcus mutans. Treatments targeting S. mutans, such as alternative strategies using probiotics, might be effective in preventing the development of dental caries. In this study, the probiotic formulation of Lactobacillus reuteri SGL01, vitamin C, and acerola was tested against S. mutans DSM20523. Antimicrobial activity was assessed by deferred antagonism and spot-on-lawn assays for L. reuteri SGL01. MIC and MBC of L. reuteri SGL01 cell-free supernatant (CFS), vitamin C, and acerola were determined with the microdilution method. Time–kill assays determined the bactericidal kinetics for each compound. The checkerboard method was used to evaluate the potential synergistic activity of CFS–vitamin C or CFS–acerola at scalar dilutions from 1 to 8X MIC. Lastly, antibiofilm activity was tested for each compound. Antimicrobial activity of L. reuteri SGL01 was first assessed by classic methods. MIC and MBC values differed for one dilution for all compounds, with values of 25% and 50% for CFS, 9.3 mg/mL and 18.7 mg/mL for vitamin C, and 18.7 mg/mL and 37.5 mg/mL for acerola, respectively. Moreover, time–kill assays confirmed the bactericidal activity at different timepoints: 4 h for CFS, 6 h for vitamin C, and 24 h for acerola. The fractional inhibitory concentration index (FICI) showed indifference for all combinations, and for associations tested at 2, 4, and 8XMIC. S. mutans biofilm production was impaired for all components, with stronger activity by vitamin C and acerola at lower concentrations. The probiotic formulation containing L. reuteri SGl01, vitamin C, and acerola extract exerts a bactericidal effect, especially strong for the CFS, as well as antibiofilm activity. Thus, the combination of these three components could be advantageous for their complementary effects, with use as a novel treatment against the development of dental caries by S. mutans. Full article

Polyphenols with antimicrobial and antibiofilm properties are gaining popularity due to their natural origins and relatively safe nature, and they have met the interest of the food industry because of their possible applicability as food preservatives. We have investigated the effect of different analogs of dimeric A-type proanthocyanidins (PACs) on four food matrix models, including unprocessed meat, fish, vegetables and dairy products previously contaminated with susceptible food pathogens. The best effects were achieved when cherry tomato was used as the food matrix for all the target bacteria (Staphylococcus aureus CECT 828, Listeria innocua CECT 910 and Bacillus cereus UJA27q) and for both temperatures tested (6 and 25 °C). Moreover, several combinations of these analogs also showed synergistic effects, mainly on S. aureus CECT 828, which may allow these antimicrobials to be used at lower levels in food matrices, which would promote their sensory acceptability. However, further studies should be conducted next to understand the mechanisms of these synergistic activities between the phenolic compounds against foodborne pathogens, as well as to ensure the absence of toxic effects when used as food preservatives. Full article

Background/Objectives: Bacterial biofilms formed by Escherichia coli pose a significant challenge in veterinary medicine due to their intrinsic resistance to antibiotics. Antimicrobial peptides (AMPs) represent a promising alternative. AMPs exert their bactericidal activity by binding to negatively charged phospholipids in bacterial membranes via electrostatic interactions, leading to membrane disruption and rapid cell lysis. Methods: In vitro assays including MIC determination, biofilm eradication testing (crystal violet, colony counts, and CLSM), swimming motility, and EPS quantification were performed. CRISPR/Cas9 was used to construct and complement a kduD mutant. A transposon mutagenesis library was screened for biofilm-defective mutants. In an in vivo murine excisional wound infection model treated with the mouse cathelicidin-related antimicrobial peptide (CRAMP-34), wound closure and bacterial burden were monitored. Gene expression changes were analyzed via RT-qPCR. Results: CRAMP-34 effectively eradicated pre-formed biofilms of a clinically relevant, porcine-origin E. coli strain and promoted wound healing in the murine infection model. We conducted a genome-wide transposon mutagenesis screen, which identified kduD as a critical gene for robust biofilm formation. Functional characterization revealed that kduD deletion drastically impairs flagellar motility and alters exopolysaccharide production, leading to defective biofilm architecture without affecting growth. Notably, the anti-biofilm activity of CRAMP-34 phenocopied aspects of the kduD deletion, including motility inhibition and transcriptional repression of a common set of biofilm-related genes. Conclusions: This research highlights CRAMP-34 as a potent anti-biofilm agent and unveils kduD as a previously unrecognized regulator of E. coli biofilm development, which is also targeted by CRAMP-34. Full article

Athamanta L. is a small genus of the Apiaceae family, comprising only sixteen species and subspecies, which are distributed in the Canary Islands, Central Europe, and the Mediterranean basin. Background/Objectives: Since the time of Dioscurides, the species of this genus have been reported to have had several ethnopharmacological activities, and some of them are also used currently. Athamanta sicula L., growing in Italy, Tunisia, Algeria, and Morocco, is the only species of this genus present in Sicily. To further explore the phytochemical profile and biological properties of this species, the present study focused on the essential oil (EO) extracted from the aerial parts of wild A. sicula populations collected in central Sicily. Methods: The chemical composition of the EO, obtained by hydrodistillation, was determined by GC–MS analysis. The presence of myristicin was confirmed by isolation and by ¹H-NMR spectroscopic characterization. Results: The EO and its main constituents have been tested for possible antimicrobial properties against several bacterial strains, showing MIC values in the of 15–30 mg/mL range, and the mechanism of action was further investigated, revealing membrane-targeting effects consistent with outer membrane permeabilization. In addition, antibiofilm activity (with up to ~80% inhibition of biofilm formation at sub-MICs), antioxidant potential (demonstrating dose-dependent radical scavenging activity), and biocompatibility with eukaryotic cells were assessed to provide a comprehensive pharmacological profile of A. sicula EO. Specifically, the most abundant constituent was myristicin (62.2%), the principal representative of the phenylpropanoid class (64.4%). Hydrocarbon monoterpenes represented the second class of the EO (27.4%), with β-phellandrene (12.2%) as the main compound. Conclusions: Myristicin emerged as the key contributor to the antimicrobial and antibiofilm activity of the EO. The obtained results highlight the relevance of A. sicula EO as a myristicin-rich essential oil with notable in vitro biological activity. Full article

Staphylococcus aureus biofilms represent a critical healthcare challenge, driving chronic infections and antimicrobial resistance. This study investigates the anti-staphylococcal efficacy of two Lactiplantibacillus strains isolated from traditional Bulgarian pickled vegetables (turshiya): L. plantarum IZITR_24 and L. paraplantarum IZITR_13. Combining whole genome sequencing (WGS) with functional assays, we established a robust genotype-to-phenotype framework to characterize their antimicrobial arsenal. Based on WGS, we identified conserved plantaricin (plnJK, plnEF) clusters in both isolates, with IZITR_13 additionally carrying genes for pediocin and enterolysin A—alongside the confirmed absence of virulence factors. Reconstituted lyophilized cell-free supernatants (LCFSs) were evaluated in dose–response microtiter assays to determine the minimum biofilm inhibitory concentration (MBIC) and minimum inhibitory concentration (MIC). Both strains demonstrated clear, dose-dependent inhibitory activity against the S. aureus growth and biofilm formation. Microscopy (SEM/CLSM) confirmed significant biofilm disruption and cell membrane permeabilization. The observed consistency between genome-inferred capacity and phenotypes highlights the strong predictive value of a genome-first screening approach for selecting bacteriocin-producing lactic acid bacteria (LAB). These findings position IZITR_24 and IZITR_13 as promising postbiotic producers with potent antibiofilm activity against S. aureus. By utilizing their stable postbiotic products rather than relying on live colonization, this study proposes a targeted, antibiotic-sparing strategy to combat persistent staphylococcal biofilms. Full article

Purpose: Periprosthetic joint infection (PJI) is a devastating complication following limb salvage surgery with tumor megaprosthetic reconstruction, leading to high morbidity and complex management. Despite advancements in prosthesis design and materials, infection rates are notably higher than in conventional arthroplasty. This narrative review synthesizes current evidence on the etiology, diagnosis, and management of PJIs in this unique setting. Methods: We conducted narrative review of literature from PubMed and Embase using keywords related to PJIs and tumor megaprostheses, aiming to summarize risk factors, diagnostic criteria, pathogen profiles, and treatment outcomes. Results: Key findings indicate that the risk of PJI is multifactorial, involving patient-related, disease-related, and treatment-related factors. Diagnosis relies on a combination of clinical presentation, serological markers, imaging, and microbiological studies, though established criteria for conventional PJI may require adaptation for tumor cases. Treatment strategies include irrigation and debridement (I&D), debridement, antibiotics, implant retention with modular component exchange (DAIR), one-stage or two-stage revision, and amputation. Success rates vary, and optimal management requires a multidisciplinary, individualized approach. However, two-stage revision is considered the gold standard for chronic PJIs. Conclusions: PJIs after tumor megaprosthetic reconstruction presents distinct challenges. Management requires a multidisciplinary, individualized approach. Future research should focus on validated diagnostic criteria for this population, novel anti-biofilm strategies, and standardized treatment protocols. Full article

The growing global threat of antimicrobial resistance (AMR), particularly in cutaneous wound infections, represents a significant clinical and economic challenge. Biofilm formation by multidrug-resistant pathogens, such as Acinetobacter baumannii, often complicates healing and leads to therapeutic failure. Antimicrobial peptides (AMPs) are a promising alternative to conventional antibiotics due to their potent membrane-disrupting mechanism of action and lower propensity to induce resistance. Background/Objectives: This study aimed to evaluate the antibacterial, antibiofilm, and in vivo efficacy of four snake venom-derived cathelicidin-like peptides—Btn (15-34) and BotrAMP14 from Bothrops atrox, and Ctn (15-34) and CrotAMP14 from Crotalus durissus—against multidrug-resistant A. baumannii, Escherichia coli, and Pseudomonas aeruginosa clinical isolates from skin infections, with emphasis on A. baumannii, a WHO priority pathogen. Methods: Minimal Inhibitory Concentration (MIC), Minimal Bactericidal Concentration (MBC), and Minimal Biofilm Inhibitory Concentration (MBIC) were determined against A. baumannii, Escherichia coli, and Pseudomonas aeruginosa. Time-kill kinetics, hemolytic activity, and cytotoxicity assays were performed. A murine skin wound infection model was established to evaluate in vivo antibacterial efficacy and safety. Results: MIC/MBC values ranged from 0.78 to 25 µM against planktonic cells. In comparison, MBIC ranged from 1.56 to 12.5 µM against biofilms. BotrAMP14 eradicated A. baumannii within 4 min, while CrotAMP14 achieved bactericidal action in 20 min at 1.56 µM. Both peptides exhibited no hemolytic activity up to 128 µM and low cytotoxicity (IC₅₀ > 128 µM). In vivo, BotrAMP14 and CrotAMP14 demonstrated significant antibacterial activity at 24 h and 48 h post-infection, respectively, surpassing that of meropenem. Conclusions: These findings suggest that BotrAMP14 and CrotAMP14 are promising topical antimicrobial agents for managing multidrug-resistant skin infections and may help address the urgent need for alternative therapies against antibiotic-resistant pathogens. Full article