Inhibit Biofilm Formation Research Articles

Innovative antifungal strategies: enhanced biofilm inhibition of Candida albicans by a modified tea tree oil formulation

IntroductionCandida albicans is a significant human pathogen with the ability to form biofilms, a critical factor in its resistance to antifungal treatments. This study aims to evaluate the antifungal activity and biofilm inhibition potential of Tea Tree Oil (TTO) derived from Melaleuca alternifolia cultivated in Vietnam.MethodsThe antifungal activity of TTO was assessed by determining the Minimum Inhibitory Concentration (MIC), Minimum Fungicidal Concentration (MFC), Minimum Biofilm Inhibitory Concentration (MBIC), and Minimum Biofilm Eradication Concentration (MBEC) using broth dilution methods. The experiments were conducted on C. albicans in both planktonic and biofilm states across concentrations ranging from 0.1 μL/mL to 10 μL/mL.ResultsTTO demonstrated significant antifungal efficacy, with a MIC of 0.1 μL/mL (∼91.217 μg/mL) and an MFC of 10 μL/mL (∼9121.7 μg/mL). It effectively inhibited biofilm formation with a recorded MBIC of 2 μL/mL (∼1824.34 μg/mL). However, MBEC values were not determinable as the concentrations tested did not achieve the eradication of more than 50% of mature biofilm within the experimental conditions.DiscussionThese findings highlight TTO as a promising natural antifungal agent with strong biofilm-inhibitory properties. However, its limited efficacy in eradicating mature biofilms underscores the need for further studies, potentially involving higher concentrations or synergistic combinations with conventional antifungal agents.

Characterization and enhanced antibiofilm activity of Annona muricata extract in combination with fluconazole against Candida albicans

Introduction: Candida albicans biofilm formation contributes significantly to antifungal resistance, necessitating new treatment strategies. Annona muricata Lin., a traditional herbal remedy, has shown promise in combating microbial infections. This study evaluated the antibiofilm activity of the methanol extract of A. muricata leaves, alone or combined with fluconazole, against C. albicans. Methods: Phytochemicals in the methanol extract were analyzed using LC-MS, biofilm metabolic activity was assessed with the XTT assay, and morphological changes were examined via scanning electron microscopy (SEM). Molecular docking evaluated the binding of compounds in the A. muricata extract to the Sap3 receptor (PDB: 2H6T). Results: LC-MS identified 17 phytochemicals in the methanol extract. The extract showed dose-dependent inhibition of biofilm formation, reaching ~60% inhibition at 240 μg/ml. Fluconazole inhibition increased from 32% to 76% as concentrations rose from 15 to 240 μg/ml. The combination of A. muricata and fluconazole enhanced inhibition, ranging from 74% to 78% at 15–240 μg/ml. SEM analysis revealed altered biofilm morphology and loss of cell integrity with the combination treatment. Phytochemicals showed high binding affinity (−9.7 to −8.0 kcal/mol) for the Sap3 enzyme, suggesting therapeutic potential. Conclusion: These findings suggest that compounds in the A. muricata methanol extract synergize with fluconazole at sub-inhibitory concentrations to suppress C. albicans biofilm formation. This paves the way for antifungal treatments that may mitigate fluconazole resistance using this plant extract.

Characterization and genomic insights into bacteriophages Kpph1 and Kpph9 against hypervirulent carbapenem-resistant Klebsiella pneumoniae

ABSTRACT The increasing incidence of infections attributed to hypervirulent carbapenem-resistant Klebsiella pneumoniae (Hv-CRKp) is of considerable concern. Bacteriophages, also known as phages, are viruses that specifically infect bacteria; thus, phage-based therapies offer promising alternatives to antibiotic treatments targeting Hv-CRKp infections. In this study, two isolated bacteriophages, Kpph1 and Kpph9, were characterized for their specificity against the Hv-CRKp K. pneumoniae NUHL30457 strain that possesses a K2 capsule serotype. Both phages exhibit remarkable environmental tolerance, displaying stability over a range of pH values (4–11) and temperatures (up to 50°C). The phages demonstrate potent antibacterial and antibiofilm efficacy, as indicated by their capacity to inhibit biofilm formation and to disrupt established biofilms of Hv-CRKp. Through phylogenetic analysis, it has been revealed that Kpph1 belongs to the new species of Webervirus genus, and Kpph9 to the Drulisvirus genus. Comparative genomic analysis suggests that the tail fiber protein region exhibits the greatest diversity in the genomes of phages within the same genus, which implies distinct co-evolution histories between phages and their corresponding hosts. Interestingly, both phages have been found to contain two tail fiber proteins that may exhibit potential depolymerase activities. However, the exact role of depolymerase in the interaction between phages and their hosts warrants further investigation. In summary, our findings emphasize the therapeutic promise of phages Kpph1 and Kpph9, as well as their encoded proteins, in the context of research on phage therapy targeting hypervirulent carbapenem-resistant Klebsiella pneumoniae.

Potential Use of Selected Natural Compounds with Anti-Biofilm Activity

Antibiotic resistance in microorganisms is an escalating global concern, exacerbated by their formation of biofilms, which provide protection through an extracellular matrix and communication via quorum sensing, enhancing their resistance to treatment. This situation has driven the search for alternative approaches, particularly those using natural compounds. This study explores the potential of phytochemicals, such as quercetin, apigenin, arbutin, gallic acid, proanthocyanidins, and rutin, known for their antibacterial properties and ability to inhibit biofilm formation and disrupt mature biofilms. The methods used in this study included a comprehensive review of current literature assessing the bioavailability, distribution, and effective concentrations of these compounds in treating biofilm-associated infections. The results indicate that these phytochemicals exhibit significant antibacterial effects, reduce biofilm’s structural integrity, and inhibit bacterial communication pathways. Moreover, their potential use in combination with existing antibiotics may enhance therapeutic outcomes. The findings support the conclusion that phytochemicals offer promising additions to anti-biofilm strategies and are capable of complementing or replacing conventional treatments, with appropriate therapeutic levels and delivery mechanisms being key to their effectiveness. This insight underscores the need for further research into their clinical applications for treating infections complicated by biofilms.

Antimicrobial Efficacy of Trifluoro-Anilines Against Vibrio Species

Vibrios are naturally present in marine ecosystems and are commonly allied with live seafood. Vibrio species frequently cause foodborne infections, with Vibrio parahaemolyticus recently becoming a significant contributor to foodborne illness outbreaks. In response, aniline and 68 of its aniline derivatives were studied due to their antibacterial effects targeting V. parahaemolyticus and Vibrio harveyi. Among these, 4-amino-3-chloro-5-nitrobenzotrifluoride (ACNBF) and 2-iodo-4-trifluoromethylaniline (ITFMA) demonstrated both antibacterial and antibiofilm properties. The minimum inhibitory concentrations (MIC) for ACNBF and ITFMA were 100 µg/mL and 50 µg/mL, respectively, against planktonic cells. The active compounds effectively suppressed biofilm formation in a manner dependent on the dosage. Additionally, these trifluoro-anilines significantly reduced virulence factors such as motility, protease activity, hemolysis, and indole production. Both trifluoro-anilines caused noticeable destruction to the membrane of bacterial cells and, at 100 µg/mL, exhibited bactericidal activity against V. parahaemolyticus within 30 min. Toxicity assays using the Caenorhabditis elegans and seed germination models showed that the compounds displayed mild toxicity. As a result, ACNBF and ITFMA inhibited the growth of both planktonic cells and biofilm formation. Furthermore, these active compounds effectively prevented the formation of biofilm on the surfaces of shrimp and squid models, highlighting their potential use in controlling seafood contamination.

CISTUS CRETICUS L.: ANTIOBESITY, ANTIMICROBIAL AND ANTIBIOFILM PROPERTIES

Objective: Cistus creticus L. is widespread in the coastal regions of Türkiye. In this study, we investigated the cytotoxic, antiobesity, antimicrobial and antibiofilm properties as well as the total phenolic and flavonoid content of both aqueous and ethanolic extracts in vitro. Material and Method: Two different extracts were prepared from the flowering aerial parts of Cistus creticus using ethanol and water. The total phenolic content and total flavonoids were determined by the Folin-Ciocalteu method and the aluminum chloride colorimetry, respectively. The effect of extracts on the cell viability of 3T3-L1 was determined by methyl thiazole tetrazolium (MTT), and the evaluation of differentiation and the effects of the plant extracts on lipid accumulation in 3T3-L1 adipocytes was performed by Oil-Red O staining. In addition, MIC values and antibiofilm activities were also investigated. Result and Discussion: The total phenol content of the EtOH and water extract was determined to be 134.2849 mg GAE/g and 96.1803 mg GAE/g, respectively. The total flavonoids in the water and EtOH extracts were found to be 33.1942 mgQE/g and 22.8338 mgQE/g, respectively. The lowest MIC values were determined for the strains Bacillus subtilis DSM 1971, Bacillus licheniformis DSM 13 and Bacillus amyloliquefaciens DSM 7, while the highest MIC concentration was found for the strains Escherichia coli and Eenterococcus gallinarum. The MIC/16 concentration of Pseudomonas aeruginosa ATCC 27853 and Escherichia coli ATCC 25922 also proved to be effective in inhibiting biofilm formation. We observed that noticeable but not strong effects on lipid accumulation were observed in 3T3-L1 adipocytes treated with EtOH extract.

The Effect of Surface Functionalization of Magnesium Alloy on Degradability, Bioactivity, Cytotoxicity, and Antibiofilm Activity

Magnesium alloys are promising biomaterials to be used as temporary implants due to their biocompatibility and biodegradability. The main limitation in the use of these alloys is their rapid biodegradation. Moreover, the risk of microbial infections, often following the implant surgery and hard to eradicate, is another challenge. Thus, with the aim of reducing biodegradability and conferring antibiofilm activity, sheets of the magnesium alloy AZ31 were properly modified with the introduction of hydroxy (polyethyleneoxy)propyl silane (PEG) and quaternary ammonium silane chains (QAS). The derivatized sheets were characterized by ATR-FTIR spectroscopy and their performances as concerns their stability, Mg2+ in vitro release, and in vitro bioactivity were evaluated as well. The results showed an increased stability with a reduction in corrosion, a slower Mg2+ ion release, and the formation of hydroxyapatite in the sheets’ surface. In addition, cytotoxicity evaluations were carried out on human gingival fibroblasts showing that the AZ31 and AZ31-PEG plates had good cytocompatibility. Finally, the antibiofilm activity on Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa was carried out by evaluating the capacity of inhibition of biofilm adhesion and formation. The results demonstrated a significant reduction in biofilm formation by Staphylococcus epidermidis on AZ31-QAS.

Cinnamic Acid Compounds (p-Coumaric, Ferulic, and p-Methoxycinnamic Acid) as Effective Antibacterial Agents Against Colistin-Resistant Acinetobacter baumannii

Colistin-resistant Acinetobacter baumannii (COLR-Ab) is an opportunistic pathogen commonly associated with nosocomial infections, and it is difficult to treat with current antibiotics. Therefore, new antimicrobial agents need to be developed for treatment. Based on this information, we investigated the antimicrobial, antibiofilm, and combination activities of p-coumaric acid (p-CA), ferulic acid (FA), and p-methoxycinnamic acid (p-MCA) against five COLR-Ab isolates. p-CA, FA, and p-MCA exhibited antimicrobial activity against COLR-Ab isolates, with minimum inhibitory concentration (MIC) values in the range of 256–128 µg/mL, 1024–512 µg/mL, and 512–128 µg/mL, respectively. The combination effects of the compounds with colistin (COL) were evaluated using a checkerboard synergy test. The combinations exhibited a synergistic effect and caused a 128- to 16-fold decrease in COL MIC values. In addition, the biofilm production capacities of the COLR-Ab isolates and the antibiofilm activities of the compounds were determined using the microtitre plate-based crystal violet (CV) technique. The compounds showed effective antibiofilm activity against strong and moderate biofilm-producing isolates, inhibiting biofilm formation by 77.5% and 19.7%. Spectrometric measurements were used to examine the effect of compounds on membrane permeability; 1.9-, 1.66-, and 1.34-fold increases in absorbance values were observed at MIC concentrations of p-CA, FA, and p-MCA, respectively. Furthermore, morphological changes caused by the compounds in the isolate were observed using scanning electron microscopy (SEM) micrographs. According to the WST assay, the compounds did not show any statistically significant cytotoxic effect on the cells (p > 0.05). These findings indicate that p-CA, FA, and p-MCA may be potential new alternative candidates against resistant A. baumannii.

Novel Leech Antimicrobial Peptides, Hirunipins: Real-Time 3D Monitoring of Antimicrobial and Antibiofilm Mechanisms Using Optical Diffraction Tomography.

Antimicrobial peptides (AMPs) are promising agents for treating antibiotic-resistant bacterial infections. Although discovering novel AMPs is crucial for combating multidrug-resistant bacteria and biofilm-related infections, their clinical potential relies on precise, real-time evaluation of efficacy, toxicity, and mechanisms. Optical diffraction tomography (ODT), a label-free imaging technology, enables real-time visualization of bacterial morphological changes, membrane damage, and biofilm formation over time. Here, a computational analysis of the leech transcriptome using an advanced AI-based peptide screening strategy with ODT to identify potential AMPs is employed. Among the 19 potential AMPs identified, hirunipin 2 demonstrates potent antibacterial activity, low mammalian cytotoxicity, and minimal hemolytic effects. It demonstrates efficacy comparable to melittin, resistance to physiological salts and human serum, and a low likelihood of inducing bacterial resistance. Microscopy and 3D-ODT confirm its disruption of bacterial membranes and intracellular aggregation, leading to cell death. Notably, hirunipin 2 effectively inhibits biofilm formation, eradicates preformed biofilms, and synergizes with antibiotics against multidrug-resistant Acinetobacter baumannii (MDRAB) by enhancing membrane permeability. Additionally, hirunipin 2 significantly suppresses pro-inflammatory cytokine expression in LPS-stimulated macrophages, highlighting its anti-inflammatory properties. These findings highlight hirunipin 2 as a strong candidate for developing novel antibacterial, anti-inflammatory, and antibiofilm therapies, particularly against multidrug-resistant bacterial infections.

Galangin synergistically revives the antibacterial activity of vancomycin against vancomycin-resistant Enterococcus faecium.

Enterococcus faecium is one of the most important opportunistic pathogens threatening human health worldwide. Resistance to vancomycin (VAN) is increasing at an alarming rate. Resurrecting antibiotics using a combination approach is a promising alternative avenue. Galangin (GAL) is a bioactive compound constituted in herbal plants. This study aimed to evaluate the synergistic activity of the combination of GAL and VAN and mode of action against vancomycin-resistant E. faecium (VREfm) strains. The minimal inhibitory concentrations against these bacteria were 8-64 μg ml-1 for VAN and 512 μg ml-1 for GAL. The VAN plus GAL combination exhibited synergistic effects against E. faecium isolates, with a fraction inhibitory concentration index of 0.26-0.28. Time-kill assays confirmed this synergism. Mechanistic studies showed that the combination induced intracellular constituent leakage, suggesting impaired membrane permeability and electron microscopy revealed peptidoglycan and membrane damage. Additionally, the GAL plus VAN combination inhibited biofilm formation and significantly reduced lipid, protein, and carbohydrate contents, as shown by Fourier-transform infrared spectroscopy (FTIR). GAL could reverse the activity of VAN against VREfm by damaging bacterial cell envelope, inhibiting biofilm formation, and reducing biomolecule contents, emphasizing its potential as a valuable adjunct to VAN in treating VREfm infections.

Unlocking the Antibacterial Potential of Naphthalimide-Coumarins to Overcome Drug Resistance with Antibiofilm and Membrane Disruption Ability against Escherichia coli.

Resistance by bacteria to available antibiotics is a threat to human health, which demands the development of new antibacterial agents. Considering the prevailing conditions, we have developed a library of new naphthalimide-coumarin moieties as broad-spectrum antibacterial agents to fight against awful drug resistance. Preliminary studies indicate that compounds 8e and 8h display excellent antibacterial activity against Escherichia coli, exceeding the performance of marketed drug amoxicillin. These drug candidates effectively inhibit biofilm formation and disrupt the biofilm virulence factor, which is accountable for the formation of strong biofilm. In addition to this, both compounds exhibit fast bactericidal properties, thus shortening the time of treatment and resisting the emergence of drug resistance for up to 20 passages. Further, biofunctional evaluation reveals that both compounds effectively disrupt the membrane, causing the leakage of cytoplasmic contents and loss in metabolic activity. Both compounds 8e and 8h efficiently induce the ROS, leading to the oxidation of GSH to GSSG, decreasing the GSH activity of the cell, and causing oxidative damage to the cells. Additionally, both compounds effectively bind with DNA to block DNA replication and form supramolecular complexes, thus exhibiting antibacterial activity. Moreover, these compounds readily bind human serum albumin with high binding constants and can be transported to the target site easily. These findings reveal that newly synthesized naphthalimide-coumarin conjugates have the potential to build as potent antibacterial agents and can be used further for clinical trials.

Facile and green synthesis of Ag/Cu bimetallic nanoparticles using waste banana peel extract for effective corrosion inhibition of mixed sulfate-reducing bacteria.

Microbiologically induced corrosion (MIC) is widespread in the oilfield industry, and new environmentally friendly materials are urgently needed to inhibit MIC with the increasing environmental requirements and microbial resistance problems. The synthesis method and cost of the materials are important factors that must be considered in the production and application. In this study, Ag/Cu bimetallic nanoparticles (BNPs) were synthesized by eco-friendly and sustainable method using waste banana peel extract (BPE) as a green reducing. The antibacterial and corrosion inhibition properties of Ag/Cu BNPs were investigated by using the enriched mixed strains containing sulfate-reducing bacteria (SRB) as model bacteria. The results of electron microscopy showed that the prepared BNPs exhibited spherical structure with about 19.0nm in size. The synthesized nanoparticles significantly inhibited the growth of mixed strains by antimicrobial experiments with minimum inhibitory concentration (MIC) value of 9.38μg/mL. The addition of Ag/Cu BNPs (9.38μg/mL) inhibited the corrosion of X65 carbon steel induced by the mixed strains with 77.9% compared to the untreated condition. Correspondingly, the number of sessile SRB cells in the solution containing Ag/Cu BNPs (9.38μg/mL) after 28 days of immersion decreased by 5-log compared with the treatment group without nanomaterials (1.1×108cells/cm2). Furthermore, the observation of the surface morphology and strains cellular microstructure of carbon steel treated with nanoparticle materials illustrated that the corrosion inhibition mechanism mainly includes destroying cell structure, affecting metabolic activities and inhibiting biofilm formation. The environmentally friendly nanoparticle materials prepared in this study have great potential in the safe and clean production of oil fields.

Nanoencapsulation of Zataria multiflora Essential Oil Containing Linalool Reduced Antibiofilm Resistance against Multidrug-resistant Clinical Strains

Background: The rise in antimicrobial resistance, caused by the production of biofilms by bacteria, is a significant concern in the field of healthcare. Nanoemulsion technology presents itself as a viable alternative in the quest to circumvent antibiotic resistance in pathogenic bacteria. Objective: The aim of this research was to form a sustainable nanoemulsion from Z. multiflora, and evaluate its antibacterial and anti-biofilm activities against the clinical isolates of Pseudomonas aeruginosa, Proteus mirabilis, and Staphylococcus aureus. Materials and Methods: Bioactive compounds of the oil were identified using GC-MS. Zataria multiflora essential oil (ZMEO) nanoemulsion was formulated as a water-dispersible nanoemulsion with a diameter of 184.88 ± 1.18 nm. The antibacterial and antibiofilm activities of the essential oil in both pure and nanoemulsion forms were assessed against pathogenic bacteria causing hospital-acquired infections using minimal inhibitory concentrations (MICs) and the microtiter method, respectively. Results: The main constituents were found to be linalool (78.66 %), carvacrol (14.25 %), and α- pinene (4.53%). Neither ZMEO nor the emulsified ZMEO showed any antimicrobial activity. However, ZMEO exhibited a low inhibition of biofilm formation by P. mirabilis, S. aureus, and P. aeruginosa. The most promising finding was that when the emulsified ZMEO was present at a concentration of 750 μg/mL, it significantly reduced biofilm formation by the aforementioned bacteria to 39.68% ± 2.62, 56.54% ± 3.35, and 59.60% ± 2.88, respectively. This result suggests that ZMEO nanoemulsion has the potential to effectively disrupt persistent biofilms and enhance the penetration of antimicrobial agents into the biofilm matrix. Conclusion: In conclusion, the study provides evidence supporting the use of ZMEO nanoemulsion as a potential treatment option for combating biofilm-related infections caused by Pseudomonas aeruginosa, Proteus mirabilis, and Staphylococcus aureus. Further research is warranted to explore the practical application of the proposed essential oil in clinical settings.

Revised Title - Quercetin Combined with Ciprofloxacin and Gentamicin Inhibits Biofilm Formation and Virulence in Staphylococcus aureus.

Revised Title - Quercetin Combined with Ciprofloxacin and Gentamicin Inhibits Biofilm Formation and Virulence in Staphylococcus aureus.

Discovery of new aliphatic metabolites with antibacterial activities from a soil-derived Streptomyces antifungus.

Fifteen new aliphatic metabolites, 2-methylpyrimidin-4(3H)-ones (1,2), 2-methoxy-2-methyl-1,2-dihydro-3H-pyrrol-3-ones (4a/4b, 5a/5b), butyrolactones (6-9), and aliphatic metabolites (16-20) as well as known pyridin-2(1H)-one (3) and butyrolactone analogues (10-15) were obtained from the fermentation broth of Streptomyces antifungus isolated from the forest soil sample collected in Tengchong, China. Pyrimidin-4(3H)-one derivatives (1, 2) with an individual 2-methylpyrimidin-4(3H)-one skeleton is a kind of rarely reported compound and were firstly obtained from natural source. The structures of the new metabolites were elucidated by comprehensive spectroscopic analysis including data from experimental and calculated ECD spectra as well as Mosher's reagent derivative method. Compounds 1, 2, 18, and 19 exhibited optimal activity against Staphylococcus aureus with MIC values ranged from 12.5 to 50 μg/mL. Further investigation revealed that 1 effectively inhibited biofilm formation and destroyed the preformed biofilm of S. aureus through oxidative damage, thereby exerting antibacterial effect.

Natural TPs inhibit biofilm formation by Multidrug-resistant Acinetobacter baumannii and biofilm-induced pulmonary inflammation

Multidrug-resistant Acinetobacter baumannii (MDRAB) infections cause elevated rates of patient deaths in intensive care units owing to the high antibiotic resistance of the clinical isolates. The advent of multidrug-resistant A. baumannii (MDRAB) strains and the formation of their biofilms are cause for concern. Tea polyphenols (TPs), which exhibit antimicrobial activity, is an ideal alternative strategy for lowering the incidence of nosocomial bacterial infections. This study was conducted to determine the effects of TPs on MDRAB. The antimicrobial and anti-biofilm activities of TPs against MDRAB were investigated in vitro using the propidium iodide assay, scanning electron microscopy, transmission electron microscopy, crystalline violet staining and real-time quantitative PCR (qPCR). The in vivo anti-biofilm and anti-inflammatory effects of TPs were studied using a rat model of MDRAB biofilm-induced pulmonary inflammation. TPs effectively inhibited the proliferation of MDRAB and damaged its cell membrane. Additionally, they inhibited MDRAB biofilm formation by reducing the content of microbial extracellular polymeric substances and altering the expression of genes related to biofilm formation. Moreover, TPs reduced pathological features of lung injury and alleviated MDRAB biofilm-induced pneumonia in rats with a tracheal cannula, attenuating the inflammatory response by inhibiting NF-κB signaling. Our findings suggest that the anti-biofilm and anti-inflammatory activities of TPs render these naturally active compounds favorable candidates for the treatment of tracheal catheter-related infections.

Pineapple (Ananas Comosus L. Merr) extract as a natural antibacterial agent for oral health: A systematic review

Background: Oral health issues such as dental caries, gingivitis, and halitosis are often caused by pathogens like Streptococcus mutans, Porphyromonas gingivalis, Streptococcus sanguinis, and Staphylococcus aureus. While chlorhexidine is effective in treating these infections, its prolonged use has adverse effects. Pineapple (Ananas comosus L. Merr), contains bioactive compounds such as bromelain, flavonoids, tannins, saponins, alkaloids, phenols, chlorine, iodine, and steroids which exhibit strong antibacterial activity. This study explores the potential of pineapple extract as a sustainable and eco-friendly alternative for oral health management, aligning with global sustainability goals. Method: The procedure used in writing this systematic review is a literature search through several databases such as PubMed, ScienceDirect, Proquest, and Google Scholar. Discussion: Pineapple extract, exhibits significant antibacterial activity against oral pathogens due to the presence of bioactive compounds such as bromelain, flavonoids, tannins, and other phytochemicals. Bromelain reduces bacterial adhesion and inhibits biofilm formation, flavonoids can interfere with bacterial metabolism and nucleic acid synthesis while tannins disrupt bacterial cell walls, leading to osmotic imbalance and cell lysis. These attributes highlight pineapple extract potential as a natural alternative for preventing oral diseases. Conclusion: Pineapple extract can provide antibacterial effects that are beneficial for oral health.

Mechanism of inhibiting periodontitis pathogenesis with various variations of inhibitors on Porphyromonas gingivalis: Systematic literature review

Background: Periodontal disease is the most prevalent disease worldwide with a prevalence of 20% to 50%, including periodontitis. Periodontitis involves complex interactions between specific pathogenic bacteria and host immune response. Microbial infections in subgingival biofilms are mainly caused by gram-negative bacteria including Porphyromonas gingivalis. Inhibition of Porphyromonas gingivalis virulence is one way to prevent periodontitis. This inhibition can be done in several ways through peptide inhibitors, quorum sensing inhibitors and natural inhibitors. Objective: This study aims to explain the mechanism of inhibiting periodontitis pathogenesis with various inhibitors on Porphyromonas gingivalis. Methods: his study employed a systematic literature review design by searching for articles based on predetermined inclusion and exclusion criteria. The search strategy used keywords and Boolean Operators from two databases (EBSCO and ProQuest). Results: he use of SAPP as a peptide inhibitor can inhibit the activity of Porphyromonas gingivalis gingipains, suppressing cytokine levels and inhibit colonization of Porphyromonas gingivalis. The use of furanone, D-ribose and BMK-Q101 as quorum sensing inhibitors can reduce Porphyromonas gingivalis in biofilms, inhibit the biosynthesis of autoinducer-2 so as to suppress the virulence factors of Porphyromonas gingivalis. The use of prenyl flavonoid as a natural inhibitor is a potent inhibitor of Arg-gingipain (Rgp) and Lys-gingipain (Kgp) and completely suppress the growth of Porphyromonas gingivalis. Conclusion: Inhibition of Porphyromonas gingivalis using peptide inhibitor, quorum sensing inhibitors and natural inhibitor can suppress virulence factors and inhibit biofilm formation of Porphyromonas gingivalis thus inhibiting the pathogenesis of periodontitis.

Inhibitory effect of andrographolide on the expression of key regulatory genes in Staphylococcus epidermidis biofilm formation.

The purpose of this study was to explore the inhibitory effect of andrographolide on the expression of key regulatory genes involved in the biofilm formation of Staphylococcus epidermidis (SE). Taking the film-producing strain Staphylococcus epidermidis SE1457 as the research object, the effect of andrographolide on the formation of Staphylococcus epidermidis biofilms was analyzed via crystal violet staining, and biofilm models of SE adhesion, aggregation and maturity were established in vitro. RT‒PCR was used to detect the effects of the expression of icaA-, atlE-, aap- and luxS-related genes of andrographolide on biofilm formation in SE. Congo red qualitative test to evaluate the ability of andrographolide to inhibit biofilm formation of Staphylococcus epidermidis. Compared with that of the control group, the light absorption value of the low- and high-concentration andrographolide groups was significantly lower, and the light absorption value of the high-concentration andrographolide group was significantly lower than that of the low-concentration andrographolide group. The levels of key genes involved in the adhesion, aggregation and maturation of icaA, atlE, aap and luxS in group C were greater than those in group B. The biofilm-forming ability of SE in group A was strong, and the colonies were obviously black. The colony in the direction of the arrow in group B was red, and the SE biofilm was inhibited. Most of the colonies in group C were red. SE biofilms were significantly inhibited. Andrographolide inhibits SE biofilm formation, and its mechanism may involve inhibition of the expression of the related genes icaA, atlE, aap and luxS.

Synthesis and characterization of a novel photothermal hydrogel composite with combined osteogenic and antibacterial activities

Abstract Cranial defect repair remains a significant challenge in neurosurgery, and designing material complexes that can support bone regeneration while minimizing complications such as infection and inflammation could help alleviate this clinical challenge. This study presents a photothermal hydrogel complex with a controlled rapid gelation process, PDA-G-A-H, which integrates photothermal polydopamine nanoparticles (PDA NPs) with gentamycin (G) and alendronate acid (A). Furthermore, the incorporation of the injectable hydrogel Pluronic F127 and collagen (H) made this composite hydrogel (PDA-G-A-H) suitable for the multifaceted needs of cranial defects. The PDA-G-A-H hydrogel exhibited superior biocompatibility, as evidenced by high cell viability and minimal hemolysis, making it a safe candidate for biomedical applications. In vitro assessments with MC3T3-E1 cells demonstrated that this hydrogel enhanced mineralization and osteogenic differentiation, and significant upregulation of key osteogenic markers was subsequently detected. The antibacterial activity of the hydrogel against Staphylococcus aureus and Staphylococcus epidermidis was also investigated. The results of the RT‒PCR analysis revealed the potential for inhibiting biofilm formation. The hydrogel composite combines biocompatibility, osteoinductive, and antibacterial potential. It has translational potential for cranial defect repair and other bone regeneration therapies.
Keywords: cranial defect, hydrogel, osteogenesis, antibacterial, biocompatibility, neurosurgery.