Search Results (2,141)

Combining antibiotics with propolis is an effective method to combat bacterial drug resistance. Nanoparticles are of interest in the antimicrobial field because of their higher drug stability, solubility, penetration power, and treatment efficacy. In this study, propolis nanoparticles (PNPs) were synthesized, and their antibacterial and anti-biofilm activities against methicillin-resistant Staphylococcus aureus (MRSA) in combination with ampicillin sodium (AS) were analyzed. The PNPs had an average particle diameter of 118.0 nm, a polydispersity index of 0.129, and a zeta potential of −28.2 mV. The fractional inhibitory concentration indices of PNPs and AS against tested MRSA strains highlighted this synergy, ranging between 0.375 and 0.5. Crystal violet staining showed that combined PNPs and AS significantly inhibited biofilm formation and reduced existing biofilm biomass. We then discovered that PNPs inhibited bacterial adhesion, extracellular polysaccharide synthesis, and mecR1, mecA, blaZ, and icaADBC gene expression. These results indicated that PNPs exerted a synergistic antibacterial effect with AS by inhibiting mecR1, mecA, and blaZ gene expressions to reduce the drug resistance of MRSA. Meanwhile, PNPs weakened bacterial adhesion and aggregation by suppressing icaADBC gene expression, allowing antibiotics to penetrate the biofilm, and exhibiting significant synergistic anti-biofilm activity. In summary, PNPs are promising candidates for combating MRSA-related diseases. Full article

Biofilms are a spontaneously formed slimy matrix of extracellular polymeric substances (EPS) enveloping miniature bacterial colonies, which aid in pathogen colonization, shielding the bacteria from antibiotics, as well as imparting them resistance towards the same. Biofilms employ a robust communication mechanism called quorum sensing that serves to keep their population density constant. What is most significant about biofilms is that they contribute to the development of bacterial virulence by providing protection to pathogenic species, allowing them to colonize the host, and also inhibiting the activities of antimicrobials on them. They grow on animate surfaces (such as on teeth and intestinal mucosa, etc.) and inanimate objects (like catheters, contact lenses, pacemakers, endotracheal devices, intrauterine devices, and stents, etc.) alike. It has been reported that as much as 80% of human infections involve biofilms. Serious implications of biofilms include the necessity of greater concentrations of antibiotics to treat common human infections, even contributing to antimicrobial resistance (AMR), since bacteria embedded within biofilms are protected from the action of potential antibiotics. This review explores various contemporary strategies for controlling biofilms, focusing on their modes of action, mechanisms of drug resistance, and innovative approaches to find a solution in this regard. This review interestingly targets the extracellular polymeric matrix as a highly effective strategy to counteract the potential harm of biofilms since it plays a critical role in biofilm formation and significantly contributes to antimicrobial resistance. Full article

Candida albicans and Staphylococcus aureus are opportunistic pathogens that cause life-threatening infections. This study focused on using photodynamic inactivation (PDI) to eliminate mixed biofilms of C. albicans–S. aureus formed on poly (urethane) (PU) discs functionalized with a nanocomposite layer containing phloxine B (PhB). Additionally, the effect of PDI on the ALS3 and HWP1 genes of C. albicans was examined in mixed biofilms. Spectral analysis showed a continuous release of PhB from the nanocomposite in Mueller–Hinton broth within 48 h, with a released amount of PhB < 5% of the total amount. The anti-biofilm effectiveness of the light-activated nanocomposite with PhB showed a reduction in the survival rate of biofilm cells to 0.35% and 31.79% for S. aureus and C. albicans, respectively, compared to the control biofilm on PU alone. Scanning electron microscopy images showed that the nanocomposite effectively reduced the colonization and growth of the mixed biofilm. While PDI reduced the regulation of the ALS3 gene, the HWP1 gene was upregulated. Nevertheless, the cell survival of the C. albicans–S. aureus biofilm was significantly reduced, showing great potential for the elimination of mixed biofilms. Full article

This study presents the synthesis and physicochemical characterization of coordination compounds formed between chrysin, a natural flavonoid, and transition metal ions: Mn(II), Co(II), and Zn(II). The complexes were obtained under mildly basic conditions and analyzed using elemental analysis, thermogravimetric analysis (TGA), silver-assisted laser desorption/ionization mass spectrometry (SALDI-MS), FT-IR spectroscopy, and ¹H NMR. The spectroscopic data confirm that chrysin coordinates as a bidentate ligand through the 5-hydroxyl and 4-carbonyl groups, with structural differences depending on the metal ion involved. The mass spectrometry results revealed distinct stoichiometries: 1:2 metal-to-ligand ratios for Mn(II) and Co(II), and 1:1 for Zn(II), with additional hydroxide coordination. Biological assays demonstrated that Co(II) and Mn(II) complexes exhibit enhanced antibacterial and anti-biofilm activity compared to free chrysin, particularly against drug-resistant Staphylococcus epidermidis, whereas the Zn(II) complex showed negligible biological activity. Full article

The escalating global challenges of antimicrobial resistance (AMR) and cancer necessitate innovative therapeutic solutions from natural sources. This study investigated the multifaceted therapeutic potential of pigment-enriched plant extracts. We screened diverse plant extracts for antimicrobial and antibiofilm activity against multidrug-resistant bacteria and fungi. Hibiscus sabdariffa emerged as the most promising, demonstrating potent broad-spectrum antimicrobial and significant antibiofilm activity. Sub-inhibitory concentrations of H. sabdariffa robustly downregulated essential bacterial virulence genes and suppressed aflatoxin gene expression. Comprehensive chemical profiling via HPLC identified major anthocyanin glucosides, while GC-MS revealed diverse non-pigment bioactive compounds, including fatty acids and alcohols. Molecular docking suggested favorable interactions of key identified compounds (Cyanidin-3-O-glucoside and 1-Deoxy-d-arabitol) with E. coli outer membrane protein A (OmpA), indicating potential antiadhesive and antimicrobial mechanisms. Furthermore, H. sabdariffa exhibited selective cytotoxicity against MCF-7 breast cancer cells. These findings establish H. sabdariffa pigment-enriched extract as a highly promising, multi-functional source of novel therapeutics, highlighting its potential for simultaneously addressing drug resistance and cancer challenges through an integrated chemical, biological, and computational approach. Full article

Nosocomial infections caused by ESKAPE pathogens represent a significant burden to global health. These pathogens may exhibit multidrug resistance (MDR) mechanisms, of which mechanisms such as efflux pumps and biofilm formation are gaining significant importance. Multidrug resistance mechanisms in ESKAPE pathogens have led to an increase in the effective costs in health care and a higher risk of mortality in hospitalized patients. These pathogens utilize antimicrobial efflux pump mechanisms and bacterial biofilm-forming capabilities to escape the bactericidal action of antimicrobials. ESKAPE bacteria forming colonies demonstrate increased expression of efflux pump-encoding genes. Efflux pumps not only expel antimicrobial agents but also contribute to biofilm formation by bacteria through (1) transport of molecules and transcription factors involved in biofilm quorum sensing, (2) bacterial fimbriae structure transport for biofilm adhesion to surfaces, and (3) regulation of a transmembrane gradient to survive the difficult conditions of biofilm microenvironments. The synergistic role of these mechanisms complicates treatment outcomes. Given the mechanistic link between biofilms and efflux pumps, therapeutic strategies should focus on targeting anti-biofilm mechanisms alongside efflux pump inactivation with efflux pump inhibitors. This review explores the molecular interplay between efflux pumps and biofilm formation, emphasizing potential therapeutic strategies such as efflux pump inhibitors (EPIs) and biofilm-targeting agents. 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

Biofilms, structured communities of microorganisms encased in an extracellular matrix, are a major cause of persistent infections, particularly when formed on medical devices. This study investigated the kinetics of biofilm formation by Escherichia coli and Pseudomonas aeruginosa, two clinically significant pathogens, on two medical-grade polymers: polyether ether ketone (PEEK) and polyamide 12 (PA12). Using a modified crystal violet staining method and spectrophotometric quantification, we evaluated biofilm development over time on polymer granules and catheter segments composed of these materials. Results revealed that PEEK surfaces supported significantly more biofilm formation than PA12, with peak accumulation observed at 24 h for both pathogens. Conversely, PA12 demonstrated reduced bacterial adhesion and lower biofilm biomass, suggesting surface characteristics less conducive to microbial colonization. Additionally, the study validated a reproducible protocol for assessing biofilm formation, providing a foundation for evaluating anti-biofilm strategies. While the assays were performed under static in vitro conditions, the findings highlight the importance of material selection and early prevention strategies in the design of infection-resistant medical devices. This work contributes to the understanding of how surface properties affect microbial adhesion and underscores the critical need for innovative surface modifications or coatings to mitigate biofilm-related healthcare risks. Full article

The most prevalent growth of Candida cells is based on biofilm development, which causes the intensification of antifungal resistance against a large range of chemicals. Nanoparticles can be synthesized using green methods via various biological extracts and reducing agents to control Candida biofilms. This study aims to compare copper oxide nanoparticles (CuONPs) synthesized through chemical methods and those synthesized using Cinnamomum verum-based green methods against Candida infections and their biofilms isolated from Iraqi patients, with the potential to improve treatment outcomes. The physical and chemical properties of these nanoparticles were characterized using Fourier-transform infrared spectroscopy (FT-IR,) scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) and X-ray diffraction (XRD). Four strains of Candida were isolated and characterized from Iraqi patients in Tikrit Hospital and selected based on their ability to form biofilm on polystyrene microplates. The activity of green-synthesized CuONPs using cinnamon extract was compared with both undoped and doped (Fe, Sn) chemically synthesized CuONPs. Four pathogenic Candida strains (Candida glabrata, Candida lusitaniae, Candida albicans, and Candida tropicalis) were isolated from Iraqi patients, demonstrating high biofilm formation capabilities. Chemically and green-synthesized CuONPs from Cinnamomum verum showed comparable significant antiplanktonic and antibiofilm activities against all strains. Doped CuONPs with iron or tin demonstrated lower minimum inhibitory concentration (MIC) values, indicating stronger antibacterial activity, but exhibited weaker anti-adhesive properties compared to other nanoparticles. The antiadhesive activity revealed that C. albicans strain seems to produce the most resistant biofilms while C. glabrata strain seems to be more resistant towards the doped CuONPs. Moreover, C. tropicalis was the most sensitive to all the CuONPs. Remarkably, at a concentration of 100 µg/mL, all CuONPs were effective in eradicating preformed biofilms by 47–66%. The findings suggest that CuONPs could be effective in controlling biofilm formation by Candida species resistant to treatment in healthcare settings. Full article

Background/Objectives: The growing demand for biocompatible and fluoride-free alternatives in oral care has led to the development of formulations containing nano-hydroxyapatite (nanoHAP). This study aimed to evaluate the antimicrobial, antibiofilm, antioxidant, and anti-inflammatory properties of a novel mouthwash containing nanoHAP, zinc lactate, D-panthenol, licorice extract, and cetylpyridinium chloride, with particular focus on its efficacy against Staphylococcus aureus and its biofilm on various dental materials. Methods: The antimicrobial activities of the mouthwash KWT0000 and control product ELM were assessed via minimal inhibitory concentration (MIC) testing against selected Gram-positive and Gram-negative bacteria and Candida fungi. Antibiofilm activity was evaluated using fluorescence and digital microscopy following 1-h exposure to biofilms of Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. The efficacy was compared across multiple dental materials, including titanium, zirconia, and PMMA. Antioxidant capacity was determined using the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) assay, and anti-inflammatory potential via hyaluronidase inhibition. Results: KWT0000 exhibited strong antimicrobial activity against S. aureus and C. albicans (MICs: 0.2–1.6%) and moderate activity against Gram-negative strains. Fluorescence imaging revealed significant biofilm disruption and bacterial death after 1 h. On metallic surfaces, especially polished titanium and zirconia, KWT0000 reduced S. aureus biofilm density considerably. The formulation also demonstrated superior antioxidant (55.33 ± 3.34%) and anti-inflammatory (23.33 ± 3.67%) activity compared to a fluoride-based comparator. Conclusions: The tested nanoHAP-based mouthwash shows promising potential in antimicrobial and antibiofilm oral care, particularly for patients with dental implants. Its multifunctional effects may support not only plaque control but also soft tissue health. Full article

Tuberaria lignosa (Sweet) Samp. (Cistaceae) is a herbaceous species native to southwestern Europe, traditionally used to treat wounds, ulcers, and inflammatory or infectious skin conditions. This study aimed to characterize the phytochemical profile of its aqueous leaf extract and evaluate its skin-related in vitro biological activities. The phenolic composition was determined using UHPLC-HRMS/MS, HPLC-DAD, and quantitative colorimetric assays. Antioxidant activity was assessed against synthetic free radicals, reactive oxygen and nitrogen species, transition metals, and pro-oxidant enzymes. Enzymatic inhibition of tyrosinase, hyaluronidase, collagenase, and elastase were evaluated using in vitro assays. Cytocompatibility was tested on human keratinocytes and NIH/3T3 fibroblasts using MTT and resazurin assays, respectively, while wound healing was evaluated on NIH/3T3 fibroblasts using the scratch assay. Antifungal activity was investigated against several Candida and dermatophyte species, while antibiofilm activity was tested against Epidermophyton floccosum. The extract was found to be rich in phenolic compounds, accounting for nearly 45% of its dry weight. These included flavonoids, phenolic acids, and proanthocyanidins, with ellagitannins (punicalagin) being the predominant group. The extract demonstrated potent antioxidant, anti-tyrosinase, anti-collagenase, anti-elastase, and antidermatophytic activities, including fungistatic, fungicidal, and antibiofilm effects. These findings highlight the potential of T. lignosa as a valuable and underexplored source of bioactive phenolic compounds with strong potential for the development of innovative approaches for skin care and therapy. Full article

Antimicrobial resistance (AMR) has emerged as a global health crisis, with methicillin-resistant Staphylococcus aureus (MRSA) representing one of the most clinically significant multidrug-resistant pathogens. In this study, three structurally unique anthracycline derivatives—keto-ester (1), 4-deoxy-ε-pyrromycinone (2), and misamycin (3)—were first isolated and characterized from the fermentation broth of the marine-derived Streptomyces tauricus NBUD24. These compounds exhibited notable antibacterial efficacy against MRSA, with minimum inhibitory concentrations (MICs) ranging from 16 to 32 µg/mL. Cytotoxicity assays confirmed their safety profile at therapeutic concentrations. The biofilm formation assay demonstrated that 4-deoxy-ε-pyrromycinone inhibited biofilm formation of MRSA ATCC43300, with an inhibition rate of 64.4%. Investigations of antibacterial mechanisms revealed that these compounds exert antibacterial effects primarily through disruption of bacterial cell wall integrity and destruction of DNA structure. These findings underscore the potential of marine-derived microbial metabolites as promising scaffolds for developing next-generation antimicrobial candidates to combat drug-resistant infections. Full article

Background/Objectives: As bacteriophage-based strategies to control bacterial pathogens continue to gain momentum, phage therapy is increasingly being explored across various fields. In the poultry industry, efforts to minimize the public health impact of Salmonella have spurred growing interest in phage applications, particularly as prophylactic and disinfecting agents. Although the disinfecting potential of bacteriophages has been recognized, in-depth studies examining their efficacy under varying environmental conditions remain limited. This study focused on evaluating the effectiveness of bacteriophages as disinfecting agents against biofilm-forming Salmonella Infantis under different environments. Methods: A comprehensive screening of biofilm-producing strains was conducted using Congo Red Agar and 96-well plate assays. Two strains with distinct biofilm-forming capacities were selected for further analysis under different environmental conditions: aerobic and microaerobic atmospheres at both 25 °C and 37 °C. The resulting biofilms were then treated with four phage preparations: three individual phages and one phage cocktail. Biofilm reduction was assessed by measuring optical density and CFU/well. Additionally, scanning electron microscopy was used to visualize both untreated and phage-treated biofilms. Results: The results demonstrated that all S. Infantis strains were capable of forming biofilms (21/21). All three phage candidates exhibited biofilm-disrupting activity and were able to lyse biofilm-embedded Salmonella cells. Notably, the lytic efficacy of the phages varied depending on environmental conditions, highlighting the importance of thorough phage characterization prior to application. Conclusions: These findings underscore that the effectiveness of bacteriophages as surface disinfectants can be significantly compromised if inappropriate phages are used, especially in the presence of biofilms. Full article

Objectives: Cefideroccol (FDC) is a siderophore cephalosporin with potent antibacterial activity against a wide range of Gram-negative multidrug-resistant (MDR) microorganisms. We investigated the anti-biofilm capacity of FDC against clinical strains. Methods: This multicenter study was conducted on 28 selected strains of MDR Gram-negative bacilli isolated from clinical samples of Pseudomonas aeruginosa (n = 5), Acinetobacter baumannii (n = 11), and Klebsiella pneumoniae (n = 12). We first determined the minimum inhibitory concentration (MIC) of each strain using the microdilution method. We also defined the minimum biofilm inhibitory concentration (MBIC) as a ≥50% reduction in tetrazolium salt (XTT) (as recommended in the 2017 Spanish Microbiology Protocols [SEIMC] for the microbiological diagnosis of infections related to the formation of biofilms). We also analyzed the reduction in the following biofilm variables after an 8 mg/mL FDC treatment: the CFU count, the cell viability, the biomass, the metabolic activity, and extracellular α or β polysaccharides. Results: The MIC₅₀ and MBIC₅₀ of FDC were 0.5 mg/L and 64 mg/L, respectively. We observed a mean (SD) fold increase in the susceptibility to FDC between planktonic and sessile cells for P. aeruginosa, A. baumannii, and K. pneumoniae of 9.60 (0.55), 6.27 (2.28), and 6.25 (2.80), respectively. When 8 mg/mL of FDC was tested, we observed that the best median (IQR) percentage reductions were obtained for cell viability and the extracellular matrix (73.1 [12.4–86.5] and 79.5 [37.3–95.5], respectively), particularly for P. aeruginosa. The lowest percentage reduction rates were those obtained for biomass. Conclusions: We demonstrated that the susceptibility to FDC was significantly reduced when strains were in a biofilm state. The best percentage reduction rates for all biofilm-defining variables were observed for P. aeruginosa. Our results need to be validated using a larger collection of clinical samples. Full article

Periodontitis is a chronic inflammatory disease caused by periodontopathic bacteria such as Porphyromonas gingivalis (P. gingivalis), which leads to alveolar bone destruction and systemic inflammation. Emerging evidence suggests that probiotics may mitigate periodontal pathology. To systematically evaluate the alleviative effects and mechanisms of different forms of probiotics, including live bacteria and postbiotics, on periodontitis, we first screened and identified Ligilactobacillus salivarius CCFM1332 (L. salivarius CCFM1332) through in vitro antibacterial and anti-biofilm activity assays. Subsequently, we investigated its therapeutic potential in a rat model of experimental periodontitis. The results demonstrated that both live L. salivarius CCFM1332 (PL) and its postbiotics (PP) significantly reduced the gingival index (GI) and probing depth (PD) in rats, while suppressing oral colonization of P. gingivalis. Serum pro-inflammatory cytokine levels were differentially modulated: the PL group exhibited reductions in interleukin-17A (IL-17A), interleukin-6 (IL-6), and interleukin-1β (IL-1β) by 39.31% (p < 0.01), 17.26% (p < 0.05), and 14.74% (p < 0.05), respectively, whereas the PP group showed decreases of 34.79% (p < 0.05), 29.85% (p < 0.01), and 19.74% (p < 0.05). Micro-computed tomography (Micro-CT) analysis demonstrated that compared to the periodontitis model group (PM), the PL group significantly reduced alveolar bone loss (ABL) by 30.1% (p < 0.05) and increased bone volume fraction (BV/TV) by 49.5% (p < 0.01). In contrast, while the PP group similarly decreased ABL by 32.7% (p < 0.05), it resulted in a 40.4% improvement in BV/TV (p > 0.05). Histological assessments via hematoxylin and eosin (H&E) and tartrate-resistant acid phosphatase (TRAP) staining confirmed that both the PL group and the PP group alleviated structural damage to alveolar bone-supporting tissues and reduced osteoclast-positive cell counts. This study suggests that live L. salivarius CCFM1332 and its postbiotics reduce alveolar bone resorption and attachment loss in rats through antibacterial and anti-inflammatory pathways, thereby alleviating periodontal inflammation in rats. Full article