Search Results (1,507)

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

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

Many industrial sectors are concerned about microbiological contamination and the associated risk of microbiologically influenced corrosion (MIC). This applies in particular to the transmission and storage of fuels in the refining industry. Exceeding a certain level of these contaminants poses a serious risk to fuel quality and can cause storage and pipeline infrastructure corrosion. This situation requires an urgent evaluation of microorganism levels in the fuel to avert such detrimental consequences. Diesel fuels containing biofuel additives are particularly susceptible to these phenomena. Traditional detection methods are limited by low sensitivity, high costs, and long turnaround times, making them unsuitable for quick, on-site, and real-time detection and monitoring. A novel approach involves the application of microwave dielectric testing to quantify microbial load in diesel fuel. Microwave dielectric spectroscopy offers a non-destructive, label-free solution, providing rapid information on microorganism presence. Combined with chemometric techniques, it effectively estimates total microorganism counts in diesel fuel. Measurement in the X-band range (8.2–12.4 GHz) takes a few seconds. Calibration with known bacterial and fungal concentrations (10³ to 10⁷ CFU/mL) and principal component analysis (PCA) of the spectroscopic data allow for clear differentiation of contamination levels, categorizing them from acceptable to hazardous. The sensitivity limit of the proposed method corresponds to a bacterial concentration of 10³ CFU/mL. Full article

Background: Non-absorbable polyvinyl alcohol sponges (Merocel) are widely used in otolaryngology for nasal and ear packing but are prone to bacterial colonization and biofilm formation, which may increase infection risk and drive frequent use of systemic antibiotics. Sustained-release drug delivery systems enable prolonged local antiseptic activity at the site of packing while minimizing systemic exposure. Methods: We developed a sustained-release varnish containing chlorhexidine (SRV-CHX) and coated sterile Merocel sponges. Antibacterial, in vitro, activity against Staphylococcus aureus and Pseudomonas aeruginosa was evaluated using kinetic diffusion assays on agar, optical density (OD₆₀₀) measurements of planktonic cultures, drop plate, ATP-based viability assays, biofilm analysis by MTT metabolic assay, crystal violet bio-mass staining, high-resolution scanning electron microscopy (HR-SEM), and spinning disk confocal microscopy. Results: SRV-CHX-coated sponges produced sustained zones of inhibition on agar plates for up to 37 days against S. aureus and 39 days against P. aeruginosa, far exceeding the usual 3–5 days of clinical sponge use. Planktonic growth was significantly reduced compared with SRV-placebo, and a bactericidal effect persisted for up to 16 days for S. aureus and 5 days for P. aeruginosa before becoming predominantly bacteriostatic. Biofilm formation was markedly inhibited, with suppression of metabolic activity and biomass for at least 33 days for S. aureus and up to 16 days for P. aeruginosa. HR-SEM and confocal imaging confirmed sparse, discontinuous biofilms and predominance of non-viable bacteria on SRV-CHX-coated sponges compared with dense, viable biofilms on the placebo controls. Conclusions: Coating Merocel sponges with SRV-CHX provides prolonged antibacterial and anti-biofilm activity against clinically relevant pathogens. This strategy may reduce dependence on systemic antibiotics and improve infection control in nasal and ear packing applications in otolaryngology. Full article

Background/Objectives: Emerging biofilms of uropathogenic bacteria, particularly P. aeruginosa, on medical devices such as urinary catheters, lead to complications in the treatment of urinary tract infections (UTI). Considering the spread of antibiotic resistance, the search for alternative efficient control options for biofilms is of great medical interest. Methods: Curcumin, 1-monolaurin, n-undecyl-α/β-l-fucopyranoside, and the fungal metabolite terrein were investigated for their influence on biofilm formation by P. aeruginosa on latex catheter pieces in artificial urine (AU), monitoring the number of colony-forming units per cm Latex-Catheter (CFU/cm Latex-Catheter). Results: Significant inhibition of P. aeruginosa biofilm formation [55.6% CFU reduction/cm²] was observed with the fungal metabolite terrein at 256 µg/mL AU. At a concentration of 512 µg/mL AU, terrein achieved almost complete inhibition of biofilm formation. n-undecyl-α/β-l-fucopyranoside inhibited biofilm formation [58.3% CFU reduction/cm²] by P. aeruginosa ATCC 27853 at 512 µg/mL AU. Compared to that, it caused an increase in biofilm formation [87.0% CFU increase/cm²] by P. aeruginosa PA 01 at 256 µg/mL AU. This study is limited by the fact that no investigations into the possible cytotoxicity of the two active substances, terrein and n-undecyl-α/β-l-fucopyranoside, on healthy eukaryotic cells have been carried out. Conclusions: Natural substances may be a promising approach to prevent the formation of P. aeruginosa biofilms. For antibacterial applications, fungal metabolites, such as terrein, offer a novel approach to prevent biofilms in urological practice. Full article

Marine biofouling significantly impacts vessel operational efficiency, with mussel species being particularly problematic due to their rapid settlement on biofilm-covered surfaces. This pilot study presents the first explicit test of whether ultrasonic treatment can disrupt the biofilm–larva interaction pathway that facilitates mussel settlement. The study evaluated ultrasonic treatment (28 kHz) as a preventive antifouling strategy targeting the mixed microbial biofilm-mediated settlement pathway of Mytilus edulis. A controlled laboratory experiment compared settlement rates on biofilm-conditioned (2.5-week mixed microbial biofilm development) and unconditioned steel plates with and without ultrasonic treatment. Under control conditions, biofilm presence increased mussel settlement odds by 49-fold (p < 0.001). Ultrasonic treatment eliminated this biofilm enhancement, maintaining settlement at baseline levels (odds ratio: 1.3, p = 0.84). The mechanism remains unclear but may involve biofilm disruption, larval behavioral avoidance, or interference with chemical cues. While limited replication (n = 2, temporal replicates, one tank per treatment per replicate) constrains statistical power and inference, the large effect size and consistency across replicates warrant additional investigation. If confirmed by increased replication and mechanistic studies, ultrasonic treatment could provide sustainable antifouling protection without chemical discharge. Full article

Foodborne diseases remain a major global challenge because pathogenic microorganisms persist in food systems, often protected by biofilms and increasing resistance to conventional chemical preservatives and sanitizers. Control strategies that were effective in the past are becoming less reliable in complex processing environments, creating a need for more precise and adaptable food-safety approaches. This review examines emerging technologies that shift food safety from broad, reactive control toward targeted, data-driven intervention. Biological tools, including bacteriophages, phage-derived enzymes, bacteriocins, quorum-sensing inhibitors, and gene-guided antimicrobial systems, are discussed for their capacity to selectively control specific pathogens while limiting unintended effects on beneficial microbiota. The review also addresses nano-enabled strategies that improve antimicrobial stability, delivery, and performance, along with plant-derived and microbial bioactive compounds that support clean-label and sustainable preservation. In parallel, advances in anti-biofilm surface engineering, such as nano-textured, contact-active, and responsive materials, are examined as preventive measures to reduce microbial attachment and persistence on food-contact surfaces. Beyond individual interventions, this review emphasizes integration within coordinated multi-hurdle systems supported by real-time monitoring and predictive analytics. Emerging digital frameworks, including digital twins of food-processing lines, are highlighted as tools to link detection, risk prediction, and targeted control. Finally, remaining knowledge gaps, regulatory challenges, and research priorities are identified, highlighting the need for realistic testing, long-term safety evaluation, standardized validation, and collaborative efforts to translate precision food-safety technologies into dependable real-world applications. Full article

Background: Staphylococcus aureus is a clinically relevant pathogen with a strong ability to form biofilms on a wide range of surfaces, which markedly reduces the effectiveness of antimicrobial treatments and contributes to therapeutic failure. Although essential oils (EOs) represent effective and economical antimicrobial alternatives, their clinical application is limited by rapid oxidation, volatility, and potential cytotoxicity. In this context, nanoencapsulation emerges as a promising strategy to improve EO stability, control release, and reduce toxicity. In this study, Tetradenia riparia essential oil was encapsulated into poly(lactide) (PLA) nanoparticles (NP) using the nanoprecipitation method. Methods: The physicochemical properties of the nanoparticles were characterized, and their antibacterial, antibiofilm, and cytotoxic activities were evaluated. Antibiofilm and antibacterial effects against S. aureus were assessed by the broth microdilution method, while cytotoxicity was determined using a VERO cell line. Results: The nanoparticles exhibited nanometric size, spherical morphology, and homogeneous structure. Both free EO and EO-loaded nanoparticles demonstrated antibacterial and antibiofilm activity against S. aureus. Importantly, EO-loaded nanoparticles were significantly less cytotoxic than free EO. Nanoencapsulation effectively prevented rapid EO evaporation and degradation, thereby enhancing stability. The nanoparticles exhibited a zeta potential of approximately −23.1 mV, indicating adequate colloidal stability. Differential scanning calorimetry revealed a reduction in melting enthalpy from 429.63 J/g (blank nanoparticles) to 115.83 J/g for EO-loaded nanoparticles, indicating decreased polymer crystallinity and a system favorable for controlled EO release. Conclusions: Overall, these findings demonstrate that nanoencapsulation of T. riparia essential oil into PLA nanoparticles preserves antimicrobial efficacy, reduces cytotoxicity, and improves physicochemical stability, supporting the potential of this nanostructured system as a promising strategy for the treatment of S. aureus biofilm-associated infections. Full article

Background: Tracheostomy procedures are associated with increased risk of nosocomial infections due to microbial colonization and biofilm formation on tube surfaces. These biofilms contribute to persistent infections and hinder clinical recovery. Plant-derived products have gained interest as alternative strategies for preventing device-associated infections. Methods: This study evaluated the phytochemical composition and the antimicrobial, anti-adherent, antibiofilm, anti-inflammatory, antioxidant, and toxicity properties of Tapirira obtusa bark extract (TOBE). Antimicrobial activity was determined by minimum inhibitory concentrations (MICs). Biofilm formation and microbial viability were assessed in mono- and mixed-species biofilms. Anti-inflammatory effects were evaluated by NF-κB inhibition and TNF-α quantification. Antioxidant activity was measured using the DPPH assay. Phytochemical analysis identified major bioactive groups, and toxicity was tested in the Galleria mellonella model. Results: TOBE exhibited notable antimicrobial activity, with MIC values between 3.9 and 31.25 µg/mL. At 78 µg/mL, the extract significantly reduced biofilm biomass and microbial viability (p < 0.05). TOBE also downregulated NF-κB activation and decreased TNF-α levels. Antioxidant assays confirmed radical-scavenging capacity. Phytochemical screening revealed phenolics, flavonoids, and tannins, and toxicity results indicated a safe profile. Conclusion: TOBE effectively inhibits microbial growth and biofilm development on orotracheal tube surfaces while exhibiting anti-inflammatory and antioxidant properties without detectable toxicity. These findings support its potential as a plant-based adjunct for preventing tracheostomy-related infections and improving patient outcomes. Full article

Pseudomonas aeruginosa (P. aeruginosa) forms biofilms that are difficult to eliminate. The matrix protects the cells, efflux pumps reduce intracellular drug levels, and dormant subpopulations survive treatment. Routine minimum inhibitory concentration (MIC) testing does not account for these features, which helps explain why infections often continue even when therapy appears appropriate. This review describes how quorum-sensing (QS) and cyclic di-guanosine monophosphate (c-di-GMP) regulate matrix production, efflux activity, and dormancy within P. aeruginosa biofilms. Important matrix components, including Psl, Pel, alginate, and extracellular DNA, slow the movement of antimicrobial agents. Regulatory proteins such as sagS and brlR increase the activity of the MexAB-OprM and MexEF-OprN efflux systems, further reducing intracellular drug concentrations. Oxygen and nutrient limitation promote persister cells and viable but nonculturable cells, with both having the ability to survive antibiotic levels that would normally be lethal. These defenses explain the gap between MIC values and biofilm-specific measurements, such as the minimum biofilm inhibitory concentration and the minimum biofilm eradication concentration. This review also summarizes emerging antibiofilm strategies. These include QS inhibitors, compounds that lower c-di-GMP, such as nitric oxide donors, nanoparticles, depolymerases, bacteriophages, and therapies that are directed at host targets. Modern diagnostic tools, such as confocal laser scanning microscopy, optical coherence tomography, and Raman spectroscopy, improve detection and guide treatment planning. A staged therapeutic approach is presented that begins with the dispersal or loosening of the matrix, continues with targeted antibiotics, and concludes with support for immune clearance. Viewing these strategies within a One Health framework highlights the role of biofilms in clinical disease and in environmental reservoirs and supports more effective surveillance and prevention. Full article

Topical antibiotics have long been used for the prevention and treatment of superficial skin and soft tissue infections; however, increasing evidence indicates that their clinical value is undermined by rising antimicrobial resistance, high rates of allergic sensitization, inadequate activity against biofilms, and a lack of wound-healing properties. Agents such as bacitracin, neomycin, polymyxin B, mupirocin, and fusidic acid act through narrow, target-specific mechanisms that facilitate resistance selection and provide limited benefit in chronic or polymicrobial wound environments. Contemporary antimicrobial stewardship frameworks therefore discourage routine use of topical antibiotics and increasingly favor non-antibiotic antiseptics with broad-spectrum activity and low resistance risk, including silver, iodine, polyhexamethylene biguanide, octenidine, and medical-grade honey. These modalities, however, primarily serve to reduce microbial burden and do not directly address the underlying biological impairments that prevent healing. Nitric oxide-releasing gels (NORGs) represent a novel class of topical antimicrobials that combine multi-target bactericidal activity with physiologic pro-healing effects. Nitric oxide exerts potent antimicrobial and antibiofilm effects via oxidative and nitrosative stress, disruption of metabolic pathways, inhibition of DNA replication, and interference with quorum sensing. Simultaneously, nitric oxide enhances angiogenesis, modulates inflammation, improves microvascular perfusion, and promotes fibroblast and keratinocyte function. Preclinical models and early-phase clinical studies demonstrate broad-spectrum efficacy—including activity against multidrug-resistant organisms—with favorable tolerability and minimal risk of resistance development. Although the current evidence base remains preliminary, NORGs offer a promising antimicrobial platform with the potential to reduce reliance on topical antibiotics while simultaneously addressing key barriers to wound healing. Larger randomized controlled trials, direct comparisons with established advanced dressings, and robust pharmacoeconomic evaluations are needed to define their optimal role within stewardship-aligned wound-care practice. Full article

Extracellular polymeric substances (EPSs) produced by actinomycetes of the genus Rhodococcus play crucial roles in their ecological success, metabolic versatility, and biotechnological value. This review summarizes existing studies of Rhodococcus EPSs, emphasizing the biochemical composition, functional attributes, and practical significance of EPSs, as well as their importance in biomedicine, bioremediation, and other applications (food industry, biomineralization) with respect to the EPS chemical composition and biological roles. Rhodococcus species synthesize complex EPSs composed primarily of polysaccharides, proteins and lipids that, like in other bacteria, support cell adhesion, aggregation, biofilm formation, and horizontal gene transfer (and can prevent exogenous DNA binding) and are highly important for resistance against toxicants and dissolution/assimilation of hydrophobic compounds. EPSs produced by different species of Rhodococcus exhibit diverse structures (soluble EPSs, loosely bound and tightly bound fractions, capsules, linear and branched chains, amorphous coils, rigid helices, mushroom-like structures, extracellular matrix, and a fibrillar structure with a sheet-like texture), leading to variations in their properties (rheological features, viscosity, flocculation, sorption abilities, compression, DNA binding, and interaction with hydrophobic substrates). Notably, the EPSs exhibit marked emulsifying and flocculating properties, contributing to their recognized role in bioremediation. Furthermore, EPSs possess antiviral, antibiofilm, anti-inflammatory, and anti-proliferating activities and high viscosity, which are valuable in terms of biomedical and food applications. Despite extensive industrial and environmental interest, the molecular regulation, biosynthetic pathways, and structural diversity of Rhodococcus EPSs remain insufficiently characterized. Advancing our understanding of these biopolymers could expand new applications in biomedicine, bioremediation, and biotechnology. Full article

Reproductive problems in farm ruminants are often linked to imbalances in the microorganisms living in the reproductive tract and their ability to form biofilms. This study examined the presence of bacteria and their biofilm-forming capacity in cows (n = 35), water buffaloes (n = 25), and goats (n = 33) in Northeastern Thailand. Samples collected from the vulva, urethral opening, and vagina were analyzed using bacterial culture, PCR, and a microtiter biofilm assay. Ten bacterial species were identified. H. trogontum and B. ovis were most common in water buffaloes and goats, while cows showed higher levels of beneficial bacteria such as B. longum and L. acidophilus. Biofilm testing showed mostly weak or non-adherent biofilms, with mean absorbance values remaining low across species. Weak biofilms were especially common in goats, whereas cows showed predominantly non-adherent patterns. Biofilm-associated genes (icaA, icaD, opp3AB) were more frequently detected in cows and buffaloes and were moderately correlated with weak biofilm formation. Overall, the results show that each ruminant species has a distinct microbial profile and biofilm behavior within its reproductive tract. These differences may influence susceptibility to reproductive infections and can guide future strategies for improving reproductive health and disease prevention in farm animals. Full article

Background: Stenotrophomonas maltophilia is an intrinsically multidrug-resistant, biofilm- forming, non-fermenter increasingly implicated in hospital-acquired infections. Evidence from non-cystic fibrosis populations, especially in the Middle East, remains sparse. Methods: We conducted a retrospective observational cohort study at a tertiary academic center (Al-Khobar, Saudi Arabia) spanning 1 May 2001–30 April 2023. Hospitalized adults (≥18 years) with culture-confirmed, clinically diagnosed S. maltophilia infection and ≥72 h of antibiotic therapy were included. The primary outcome was all-cause mortality (14-day, 30-day, 1-year). Secondary outcomes were clinical response, microbiological eradication, and infection recurrence. Predictors of 30-day mortality were assessed using multivariable logistic regression; 14-day mortality was analyzed by Kaplan–Meier/log-rank according to susceptibility-guided versus alternative therapy. Results: Of 539 patients with positive cultures, 436 met the inclusion criteria. Mean age was 60.5 ± 19.3 years; 62.2% were male. Most infections were hospital-acquired (92.9%); pneumonia composed 64.7% and bloodstream infection 15.4%. Polymicrobial growth occurred in 55.5% (predominantly Gram-negative co-isolation). Susceptibility was 95.1% to trimethoprim–sulfamethoxazole, 76.4% to levofloxacin, and 43.6% to ceftazidime. Mortality at 14 days, 30 days, and 1 year was 22.8%, 37.9%, and 57.2%, respectively. On multivariable modelling, intensive care unit (ICU) admission, leukocytosis, neutrophilia, anemia, and thrombocytopenia independently predicted 30-day mortality. Susceptibility-guided therapy was associated with improved 14-day survival (log-rank p = 0.033). Conclusions: In this large, long-running non-cystic fibrosis cohort, host acuity and early alignment of treatment to susceptibility data were dominant drivers of outcome. High polymicrobial burden and limited reliably active agents underscore the need for meticulous stewardship, robust infection prevention, and cautious interpretation of S. maltophilia antimicrobial susceptibility testing. Full article

Objectives: Despite the increasing scientific evidence regarding the application of Cranberries in dentistry, a comprehensive understanding of their potential benefits, active constituents, and mechanisms of action remains lacking. Consequently, this narrative review aims to meticulously analyze and consolidate the existing scientific literature on the utilization of Cranberries for the prevention and treatment of oral diseases. Materials and Methods: Electronic databases (PubMed, Scopus, and Web of Science) were searched up to October 2025. This review included in vitro, in vivo, and clinical research studies. A two-phase selection process was carried out. In phase 1, two reviewers independently screened titles and abstracts to identify potentially eligible studies. In phase 2, the same reviewers performed the full-text assessments of the eligible articles. Results: Among the 93 eligible articles, most assessed Cranberry use in Cariology (n = 28) and Periodontics (n = 26). Biofilm and microbial virulence factors (n = 46) were the most frequently studied topics. Cranberry extract (n = 32) and high-molecular-weight non-dialyzable material (NDM) (n = 23) were the most evaluated Cranberry fractions. Overall, Cranberry-derived compounds were identified as non-toxic and demonstrated promising antimicrobial activity against dental caries-related microorganisms in preclinical studies (n = 20). Regarding periodontal and peri-implant diseases, Cranberry demonstrated host immune modulator effects, counteracting the inflammatory and destructive mechanisms (n = 8). Additionally, Cranberries presented benefits in reducing the inflammation associated with periodontal disease and temporal mandibular joint lesions (n = 1). Regarding dental erosion, Cranberry inhibited dentin erosion (n = 4); however, no effect was observed on enamel lesions (n = 2). As an antioxidant agent, Cranberry showed effectiveness in preventing dental erosion (n = 18). Beyond that, Cranberry neutralized reactive oxygen species generated immediately after dental bleaching, enhancing bond strength (n = 2) and counteracting the oxygen ions formed on the tooth surface following bleaching procedures (n = 3). In osteoclastogenesis assays, A-type proanthocyanidins inhibited bone resorption (n = 1). In osteogenic analysis, preservation of hydroxycarbonate apatite deposition and an increase in early and late osteogenic markers were observed (n = 2). Conclusions: Cranberry bioactive compounds, both individually and synergistically, exhibit substantial potential for diverse applications within dentistry, particularly in the prevention and management of oral and maxillofacial diseases. This review provides insights into the plausible incorporation of Cranberries in contemporary dentistry, offering readers an informed perspective on their potential role. Full article