Search Results (463)

Background: Trichosporon spp. are opportunistic fungi, capable of causing infection, especially in critically ill individuals who often use broad-spectrum antibiotics, invasive devices, and have comorbidities. Objectives The aim of this study was to analyze individuals’ clinical characteristics, evaluate tolerance to biocides, as well as biofilm formation and efflux pump activity in isolates of Trichosporon asahii. Methods: Clinical isolates of T. asahii collected between 2020 and 2023 from both hospitalized and non-hospitalized individuals, of both sexes, regardless of age, were tested for tolerance to sodium hypochlorite, hydrogen peroxide, benzalkonium chloride, and ethyl alcohol. Efflux pump activity was also assessed using ethidium bromide, and biofilm formation was measured with the Safranin test. Clinical parameters such as outcomes, source, and length of hospitalization were analyzed through electronic medical records. Results: A total of 37 clinical isolates of T. asahii were identified. Thirty-three (83.8%) isolates were from hospitalized individuals, with 81.82% collected in ICUs, an average hospital stay of 35 days, and a mortality rate of 51.6%. The tested strains displayed the largest mean inhibition zone for 2% sodium hypochlorite, indicating lower tolerance. A high level of efflux pump expression was detected among clinical isolates. Biofilm formation was detected in 25/67.5% of the isolates. Conclusions: These findings highlight the clinical relevance of T. asahii, particularly in critically ill individuals, and underscore the pathogen’s ability to tolerate biocides, express efflux pumps, and form biofilms, all of which may contribute to its persistence and pathogenicity in hospital environments. Enhanced surveillance and effective microbial control measures are essential to mitigate the risks associated with T. asahii infections. Full article

Background/Objectives: Schoolteachers play a central role in shaping their students’ beliefs and attitudes towards oral health. Our aim was to investigate the oral and periodontal health knowledge of schoolteachers in Riyadh and factors affecting this knowledge. Methods: Government schoolteachers from representative areas of Riyadh (n = 895) responded to a structured questionnaire. Descriptive statistics, t-tests, one-way analysis of variance, and multiple linear regression (p ≤ 0.05). Results: Teachers demonstrated good basic oral/periodontal health knowledge (mean score = 60.21 ± 10.68). Most knew that toothbrushing is necessary to preserve dental (78.66%) and periodontal (57.88%) health; that gingival bleeding (74.41%), swelling (64.25%), and abscess formation (52.96%) are signs of periodontal disease; about 63% identified dental biofilm as an etiologic factor, and 58% knew that periodontitis may cause gingival recession and influence systemic health (74.07%). However, only 38% knew that dental flossing is necessary to preserve periodontal health, and 66.03% believed that gingival health can be restored with a special toothpaste. Teachers who were female, older in age, worked in north Riyadh, and taught the intermediate stage demonstrated statistically significantly better knowledge than the other categories. Conclusions: The studied sample of schoolteachers possesses acceptable basic oral health knowledge but has inadequate knowledge of periodontal health. Factors influencing teachers’ knowledge were age, gender, region of work, and teaching stage. Full article

Background/Objectives: There is an increasing incidence of fungal infections in conjunction with the rise in resistance to medical treatment. Antimicrobial resistance is frequently associated with virulence factors such as adherence and the capacity of biofilm formation, which facilitates the evasion of the host immune response and resistance to drug action. Novel therapeutic strategies have been developed to overcome antimicrobial resistance, including the use of different type of nanomaterials: metallic (Au, Ag, Fe₃O₄ and ZnO), organic (e.g., chitosan, liposomes and lactic acid) or carbon-based (e.g., quantum dots, nanotubes and graphene) materials. The objective of this study was to evaluate the action of nanoparticles of different synthesis and with different coatings on fungi of medical interest. Methods: Literature research was conducted using PubMed and Google Scholar databases, and the following terms were employed in articles published up to June 2025: ‘nanoparticles’ in combination with ‘fungal biofilm’, ‘Candida biofilm’, ‘Aspergillus biofilm’, ‘Cryptococcus biofilm’, ‘Fusarium biofilm’ and ‘dermatophytes biofilm’. Results: The utilization of nanoparticles was found to exert a substantial impact on the reduction in fungal biofilm, despite the presence of substantial variability in minimum inhibitory concentration (MIC) values attributable to variations in nanoparticle type and the presence of capping agents. It was observed that the MIC values were lower for metallic nanoparticles, particularly silver, and for those synthesized with polylactic acid compared to the others. Conclusions: Despite the limited availability of data concerning the stability and biocompatibility of nanoparticles employed in the treatment of fungal biofilms, it can be posited that these results constitute a significant initial step. Full article

Candida albicans complications challenged researchers and health overseers to discover effectual agents for suppressing such yeast growth, biofilm formation and conversion to hyphal form. The nanomaterials and their composites provided extraordinary bioactivities and functionalities as antimicrobial preparations. The extraction of chitosan (BCt) from honeybee corpuses was achieved as an innovative biopolymer for nanocomposite formation. The green (bio)synthesis of nanosilver (AgNPs) was promisingly performed using royal jelly (RJ) as a mediator of synthesis. The RJ-synthesized AgNPs had an average diameter of 3.61 nm and were negatively charged (−27.2 mV). The formulated nanocomposites from BCt/RJ/AgNPs at 2:1 (F1), 1:1 (F2), and 1:2 (F3) ratios had average diameters of 63.19, 27.65, and 52.74 nm, where their surface charges were +33.8, +29.3, and −11.5 mV, respectively. The infrared (FTIR) analysis designated molecules’ interactions, whereas the transmission microscopy emphasized the homogenous distribution and impedance of AgNPs within the biopolymers’ nanocomposites. Challenging C. albicans strains with nanomaterials/composites pinpointed their bioactivity for suppressing yeast growth and biofilm formation; the F2 nanocomposite exhibited superior actions, with the lowest inhibitory concentrations (MICs) of 125–175 mg/L, whereas the MIC ranges were 150–200 and 175–225 mg/L for F3 and F1, respectively. The different BCht/RJ/AgNP nanocomposites could entirely suppress the biofilm formation of all C. albicans strains. The scanning microscopy reflected the nanocomposite efficiency for C. albicans cell destruction and the complete suppression of hyphal formation. The application of generated BCht/RJ/AgNP nanocomposites is strongly recommended as they are effectual, natural and advanced materials for combating C. albicans pathogens. Full article

Background/Objectives: Children with an oral presence of Candida spp. have an elevated prevalence of dental caries. As an alternative to conventional antifungal drugs, the use of biofilm-modulating strategies, such as probiotic bacteria, may be a sustainable option. Probiotics are live microorganisms that have beneficial health effects, while prebiotics are compounds in food that foster the growth or activity of the beneficial microorganisms. The aim of this paper was to review current clinical findings regarding the antifungal effects of pre- and probiotic supplements, including syn- and postbiotics, in children. Methods: We searched two databases (PubMed and Google Scholar) for controlled clinical trials published in English up to 20 April 2025, and two authors scanned the abstracts independently for relevance. The selected full-text papers were reviewed and assessed for risk of bias. Results: Four articles published between 2013 and 2025 were included in this review, covering a total number of 208 caries-active children between 3 and 14 years of age. Study designs were heterogeneous, and we observed conflicting results: two studies with probiotic streptococci failed to demonstrate any beneficial effects on the counts of salivary C. albicans, while interventions with L. plantarum and L. rhamnosus significantly reduced C. albicans compared with controls. None of the included reports displayed a low risk of bias. No clinical studies utilizing prebiotics, synbiotics, or postbiotics were retrieved. Conclusions: We found insufficient evidence concerning the antifungal effects of probiotic supplements in children. Therefore, we recommend future clinical trials to explore the ability of pre-, pro-, and postbiotic interventions to affect cross-kingdom biofilms in order to support a balanced and health-associated composition of the dental biofilm in children. Full article

Multidrug-resistant (MDR) biofilm infections characterized by densely packed microbial communities encased in protective extracellular matrices pose a formidable challenge to conventional antimicrobial therapies and are a major contributor to chronic, recurrent and device-associated infections. These biofilms significantly reduce antibiotic penetration, facilitate the survival of dormant persister cells and promote horizontal gene transfer, all of which contribute to the emergence and persistence of MDR pathogens. Metal nanoparticles (MNPs) have emerged as promising alternatives due to their potent antibiofilm properties. However, conventional synthesis methods are associated with high costs, complexity, inefficiency and negative environmental impacts. To overcome these limitations there has been a global push toward the development of sustainable and eco-friendly synthesis approaches. Recent advancements have demonstrated the successful use of various plant extracts, microbial cultures, and biomolecules for the green synthesis of MNPs, which offers biocompatibility, scalability, and environmental safety. This review provides a comprehensive overview of recent trends and the latest progress in the green synthesis of MNPs including silver (Ag), gold (Au), platinum (Pt), and selenium (Se), and also explores the mechanistic pathways and characterization techniques. Furthermore, it highlights the antibiofilm applications of these MNPs emphasizing their roles in disrupting biofilms and restoring the efficacy of existing antimicrobial strategies. Full article

The growing prevalence of bacterial infections and the alarming rise of antimicrobial resistance (AMR) have driven the need for innovative antimicrobial coatings for medical implants and biomaterials. However, implant surface properties, such as roughness, chemistry, and reactivity, critically influence biological interactions and must be engineered to ensure biocompatibility, corrosion resistance, and sustained antibacterial activity. This review evaluates three principal categories of antimicrobial agents utilized in surface functionalization: metal/metaloxide nanoparticles, antibiotics, and phytochemical compounds. Metal/metaloxide-based coatings, especially those incorporating silver (Ag), zinc oxide (ZnO), and copper oxide (CuO), offer broad-spectrum antimicrobial efficacy through mechanisms such as reactive oxygen species (ROS) generation and bacterial membrane disruption, with a reduced risk of resistance development. Antibiotic-based coatings enable localized drug delivery but often face limitations related to burst release, cytotoxicity, and diminishing effectiveness against multidrug-resistant (MDR) strains. In contrast, phytochemical-derived coatings—using bioactive plant compounds such as curcumin, eugenol, and quercetin—present a promising, biocompatible, and sustainable alternative. These agents not only exhibit antimicrobial properties but also provide anti-inflammatory, antioxidant, and osteogenic benefits, making them multifunctional tools for implant surface modification. The integration of these antimicrobial strategies aims to reduce bacterial adhesion, inhibit biofilm formation, and enhance tissue regeneration. By leveraging the synergistic effects of metal/metaloxide nanoparticles, antibiotics, and phytochemicals, next-generation implant coatings hold the potential to significantly improve infection control and clinical outcomes in implant-based therapies. Full article

This study develops a dual-mode antibacterial orthodontic adhesive by integrating quaternary ammonium salt-modified large-pore mesoporous silica nanoparticles (QLMSN@CHX). The material integrates two antibacterial mechanisms: (1) contact killing via covalently anchored quaternary ammonium salts (QACs) and (2) sustained release of chlorhexidine (CHX) from radially aligned macropores. The experimental results demonstrated that QLMSN@CHX (5 wt%) achieved rapid biofilm eradication (near-complete biofilm eradication at 24 h) and prolonged antibacterial activity, while maintaining shear bond strength comparable to commercial adhesives (6.62 ± 0.09 MPa after 30-day aging). The large-pore structure enabled controlled CHX release without burst effects, and covalent grafting ensured negligible QAC leaching over 30 days. The composite demonstrated good biocompatibility with human dental pulp mesenchymal stem cells at clinically relevant concentrations. This dual-mode design provides a clinically viable strategy to combat bacterial contamination in orthodontic treatments, with potential applications in other oral infections. Future studies will focus on validating efficacy in complex in vivo biofilm models. Full article

Background/Objectives: Root canal infections represent a serious challenge to the success of endodontic treatment. The most commonly used antimicrobial irrigants, such as sodium hypochlorite (NaOCl), have certain limitations, while endodontic biofilms pose a significant microbiological complexity in the endodontic field. Silver nanoparticles (AgNPs) have emerged as a promising irrigant option in root canal treatments; however, few studies are focusing on endodontic biofilms. This work aimed to evaluate the antimicrobial and anti-adherence properties of AgNPs against clinically isolated bacteria taken directly from patients with various pulp and periapical diseases. Methods: AgNPs of two sizes were synthesized and characterized. The bactericidal and anti-adherence activities of AgNPs were evaluated through microbiological assays using experimental in vitro and ex vivo tests on oral biofilms taken from patients with symptomatic apical periodontitis (AAP) and pulp necrosis (PN). NaOCl solution was used as the gold standard. Results: The size of AgNPs was uniformly distributed (13.2 ± 0.4 and 62.6 ± 14.9 nm, respectively) with a spherical shape. Both types of nanoparticles exhibited good antimicrobial and anti-adherence activities in all microbiological assays, with a significant difference from NaOCl for in vitro and ex vivo models (p < 0.05). The inhibitory activity of AgNPs is mainly related to the type of microbiological sample and the exposure time. The antibacterial substantivity of both nanoparticle sizes was time-dependent. Conclusions: AgNPs may represent a promising antimicrobial option as an endodontic irrigant during conventional root canal treatments to prevent and control endodontic infections. Full article

Background: Dithiolopyrrolones (DTPs), such as holomycin and thiolutin, exhibit potent antibacterial activities. DTPs contain a disulfide within a unique bicyclic scaffold, which may chelate metal ions and disrupt metal-dependent cellular processes once the disulfide is reductively transformed to thiols. However, the contribution of the intrinsic redox mechanism of DTPs to their antibacterial activity remains unclear. Herein we used pyrroloformamide (Pyf) A, a DTP with a unique formyl substituent, as a prototype to study the antibacterial potential and mechanism against ESKAPE pathogens, in particular carbapenem-resistant Klebsiella pneumoniae (CRKP). Methods: The antibacterial and anti-biofilm activities of Pyf A were mainly assessed against clinical CRKP isolates. Propidium iodide staining, scanning electron microscopy, glutathione (GSH) quantification, and reactive oxygen species (ROS) analysis were utilized to infer its anti-CRKP mechanism. The synergistic antibacterial effects of Pyf A and AgNO₃ were evaluated through checkerboard and time-kill assays, as well as in vivo murine wound and catheter biofilm infection models. Results: Pyf A exhibited broad-spectrum antibacterial activity against ESKAPE pathogens with minimum inhibitory concentrations ranging from 0.25 to 4 μg/mL. It also showed potent anti-biofilm effects against CRKP. Pyf A disrupted the cell membranes of CRKP and markedly depleted intracellular GSH without triggering ROS accumulation. Pyf A and AgNO₃ showed synergistic anti-CRKP activities in vitro and in vivo, by disrupting both GSH- and thioredoxin-mediated redox homeostasis. Conclusions: Pyf A acts as a GSH-depleting agent and, when combined with AgNO₃, achieves dual-targeted disruption of bacterial thiol redox systems. This dual-targeting strategy enhances antibacterial efficacy of Pyf A and represents a promising therapeutic approach to combat CRKP infections. Full article

Chronic wounds, including diabetic foot ulcers and pressure sores, are becoming more prevalent due to aging populations and increased metabolic problems. These wounds often persist due to impaired healing, chronic inflammation, oxidative stress, and infections caused by multidrug-resistant pathogens, making conventional treatments—including antibiotics and antiseptics—largely inadequate. This creates an urgent need for advanced, biologically responsive therapies that can both combat infection and promote tissue regeneration. Probiotics have surfaced as a viable option owing to their capacity to regulate immune responses, impede pathogenic biofilms, and generate antibacterial and antioxidant metabolites. However, their clinical application is limited by poor viability, sensitivity to environmental conditions, and short retention at wound sites. Nanotechnology-based delivery systems address these limitations by protecting probiotics from degradation, enhancing site-specific delivery, and enabling controlled, stimuli-responsive release. Encapsulation techniques using materials like chitosan, PLGA, liposomes, nanogels, nanofibers, and microneedles have shown significant success in improving wound healing outcomes in preclinical and clinical models. This review summarizes the current landscape of chronic wound challenges and presents recent advances in probiotic-loaded nanotechnologies. It explores various nano-delivery systems, their mechanisms of action, biological effects, and therapeutic outcomes, highlighting the synergy between probiotics and nanocarriers as a novel, multifaceted strategy for managing chronic wounds. Full article

The contamination of natural waters with heavy metals is a global problem. Biosorption is an environmentally friendly and effective technology that offers advantages when metals are present in low concentrations. It also facilitates the recovery and conversion of metals, which are valuable resources. The removal capacity of Ag(I) and Zn(II) ions by Staphylococcus epidermidis CECT 4183 and the ability of its cell extract to synthesize Ag/AgCl and ZnO nanoparticles were investigated. Their biocidal capacity was evaluated. The factors involved were optimized and the mechanisms were studied. The optimal conditions for Ag(I) biosorption were pH 4.5 and a biomass dose of 0.8 g/L. For Zn(II), the biomass dose was 0.2 g/L and pH 4.2. A maximum biosorption capacity (Langmuir model) of 47.43 and 65.08 mg/g, respectively, was obtained. The cell extract promoted the synthesis of Ag/AgCl and ZnO nanoparticles with average sizes below 35 nm. The ZnO nanoparticles exhibited excellent inhibitory properties against planktonic cells of five microbial strains, with MIC values ranging from 62.5 to 250 µg/mL. Their response to biofilms remained between 70% and 100% inhibition at low concentrations (125 µg/mL). The studied bacteria show potential to remove heavy metals and promote the environmentally friendly synthesis of biocidal nanoparticles. Full article

Background: Durable mechanical circulatory support (DMCS) infections remain a serious challenge. Ventricular assist device (VAD)-specific driveline infections (DLIs) are the most common type; however, no consensus exists on their surgical management. We aimed to define the incidence, risk factors, and microbiology of DLIs and discuss the surgical treatment modalities. Methods: We retrospectively reviewed 90 patients who underwent a left or biventricular ventricular assist device (LVAD or BiVAD) implantation with either a HeartMate 2 (Abbott), HeartWare HVAD (Medtronic), or HeartMate 3 (Abbott) in a single center between 1 March 2011 and 30 May 2023. Results: DLIs were detected in 20 (21.5%) patients during the follow-up. The mean duration of VAD support was 561.1 ± 833.2 days (1–4124 days), while it was 1277.9 ± 621.6 days in the DLI group. An extended duration of VAD support was associated with higher incidence rates of late-onset DLIs (p < 0.05). A younger age and lower plasma albumin levels were independent predictive factors for the risk of a DLI, with a hazard ratio of 9.77 (95%CI: 1.3–74.5) and 10.55 (95%CI: 1.40–79.35), respectively. The removal of the biofilm with velour and DL relocation through the rectus muscle combined with vacuum-assisted strategies (VAC) were performed in nine patients. One patient developed a recurrent infection, and another patient with a deep DLI subsequently received a heart transplant. No patient underwent a device exchange for an intractable DLI. Conclusions: Our results suggest that DLIs are common infectious complications after VAD implantation, which endanger patient autonomy, and impair their quality of life and overall survival. A DL relocation through the rectus muscles and VAC strategies have a role in controlling DLIs. Full article

Polyphenols show promising application prospects as a novel natural disinfectant for drinking water. This study employed a simulated pipe network system to investigate the effects of tea polyphenols at an initial concentration of 5 mg/L on the characteristics of biofilm on pipe walls and microbial community succession patterns under different water ages (12–48 h). The results showed that with increasing water age, the tea polyphenol residual concentration gradually decreased, and the biofilm structure significantly evolved: the surface roughness increased from 5.57 nm to 32.8 nm, and the biofilm thickness increased from 40 nm to 150 nm. Microbial community diversity exhibited a trend of first increasing and then decreasing, with the Shannon index reaching its peak (2.847) at a water age of 36 h and remaining significantly higher than the control group (1.336) at all stages. High-throughput sequencing revealed a transition from a single dominant genus of Methylophilus (54.41%) at a water age of 12 h to a multi-genus coexistence pattern at a water age of 48 h, with Methylophilus (24.33%), unclassified_Saprospiraceae (21.70%), and Hydrogenophaga (16.52%) as the main dominant groups. Functional bacterial groups exhibited temporal changes, with biofilm colonization-related genera (Caulobacter, Sphingobium) reaching their peaks at 36 h, while special metabolic genera (Methylophilus, Hydrogenophaga) dominated at 48 h. Potential pathogens in the tea polyphenol treatment groups were effectively controlled at low levels (<0.21%), except for a temporary increase in Legionella (6.50%) at 36 h. Tea polyphenols’ selective inhibition mechanism helps suppress the excessive proliferation of specific genera and reduces the risk of potential pathogen outbreaks. This has important implications for ensuring the microbiological safety of drinking water. Full article

Legionella pneumophila (L. pneumophila), the bacteria causing Legionnaires’ disease, a severe pneumonia with high morbidity and mortality globally. The underreporting of this disease is marked particularly in low-income African countries, where data on Legionellosis remains extremely limited. Gauteng, South Africa’s most densely populated province, faces challenges such as rapid urbanisation, limited access to sanitary facilities, and ageing infrastructure, which can compromise drinking water quality by increasing the presence of bacteria within the water distribution systems. Although research on Legionella in South Africa has been conducted, no research has compared its prevalence in urban and rural households in the country. This study examines the presence and distribution of L. pneumophila and amoeba-associated strains in water distribution systems in both urban (Hillbrow and Atteridgeville) and rural (Zandspruit and Melusi) areas in Gauteng province in South Africa. In total, 134 water samples were obtained from tap faucets and storage containers, and 260 biofilm samples were obtained from tap faucets, storage containers, and toilet bowls. Water samples were analysed for Escherichia coli (E. coli) using the IDEXX Colilert^® and for L. pneumophila using the IDEXX Legiolert^TM assay. Both water and biofilm samples were analysed for evidence of amoeba-associated Legionella using the amoeba enrichment technique. The Colilert assay detected total coliforms in 13% of the urban samples and 25% of the rural samples. The Legiolert^TM assay detected L. pneumophila in 52% of urban and 78% of rural samples. Amoeba-associated L. pneumophila was confirmed in 35% of urban samples and 25% in rural samples. The conventional PCR confirmed L. pneumophila in 81% of both urban and rural samples, while real-time PCR detected L. pneumophila in 97% of urban and 100% of rural samples. In total, 111 water and 19 biofilm samples tested positive for the presence of L. pneumophila across the four areas. These results revealed that L. pneumophila is prevalent in both urban and rural water systems in Gauteng. Full article