Pathogenic Biofilms Research Articles

Genotypic investigation of drugs resistance and biofilm genes among ciprofloxacin-resistant Pseudomonas aeruginosa isolated from burn patients

Burn patients are the serious targets of hospital-acquired infection occurred by Pseudomonas aeruginosa ( P. aeruginosa) , which is a main cause of burn patients morbidity and mortality, so this study aimed to molecular investigation of genes associated with antibiotic resistance among ciprofloxacin-resistant Pseudomonas aeruginosa. Current study involved 168 burn patients involved 107(63.69%) and 61 (36.3%) were females and male respectively, the results showed 132(78.57%) gram negative bacteria and 27(16.0%) gram positive bacteria while 9(5.3%) no bacterial growth. The results of Vitek-2 compact system recorded 75(44.64%) as P. aeruginosa isolates. Results of ciprofloxacin susceptibility showed 29(38.67%), while 34(45.33%) and 12(16%) of isolates were intermediate and sensitive respectively. Congo red agar assay was applied in current study for qualitative evaluation of pathogenic biofilm were 23/29 (79.31%), and 6/26(20.86%) as high, and moderate biofilm producer among isolates respectively. Result of Polymerase chain reaction (PCR) showed that gyrB was recorded among ciprofloxacin-resistant P. aeruginosa at rate 28/29 (96.55%). At same respect. results of efflux pump genes for oqxA and oqxB genes were detected among this pathogen at rate 26/29 (89.65%) and 29/29(100%) respectively. outer membrane genes, revealed that mexR gene was 27/29 (93.1%), while the spreading of the oprD gene was 26/29(89.65%). Results of molecular detection about colistin resistance genes revealed that the mcr-3 gene was 8/29 (27.58%), but genes of mcr-1 and mcr-2 were no detected in this work, Finally, results showed that 23/29 (79.31%) of ciprofloxacin-resistant P. aeruginosa were harbored pml gene.

Sustainable deployment of host defense peptides for targeted quorum sensing inhibition

The intriguing fact is that exploration of Host Defense Peptides (HDPs), usually known as antimicrobial peptides, has become increasing because of their multifaceted nature, which makes them extremely important for immunity and possible medication. HDPs are short peptides which are produced by the human body as well as other organisms and part of the immune system of the organism that is where they play an essential role. The peptides flexibly promote the antimicrobial resistance to different bacteria, fungi, viruses, and parasites. The main mechanisms work via microorganism cell membrane disruption, perturbation of nucleic acid synthesis, and modulation of the immune response. It is important to mention that the application of HDPs is a fleeting remedy to antibiotics counteracting the development of antibiotics resistance. The fact that they can attack the pathogenic biofilms which are particularly difficult target of conventional therapeutics is undoubtedly additional benefit of using biophotons for clinical purposes – they would be highly helpful in the therapy of chronic diseases and wound healing. HDPs’ sustainability is reinforced by its biodegradability and practically no environmental impacts compared to pharmaceuticals based on the chemical elements that is the major concern in the medical sphere nowadays. Their diverse functions and the respective efficacy against resistant strains are very much active research activities right now, thereby making clear the role of these probiotics in addressing the present and future health hurdles.

Antibiofilm potential of biosurfactant produced by Bacillus aerius against pathogen bacteria

Biosurfactants (BS) derived from various microbes forms an alternative to chemical surfactants, which have many applications in food, petroleum, cosmetics, pharmaceutical industries. The present work aims to explore and identify new molecules and methods for the treatment of pathogenic bacterial biofilms. The findings of screening tests demonstrate Bacillus aerius ability to synthesize a surfactant with an emulsification index (EI24%) of 72.2% and a critical micellar concentration (CMC) of 60 mg/L. This BS effectively reduces surface tension, leading to a significant decrease from an initial value of 72 mN/m to 26 mN/m. This BS have been preliminarily characterized, Molecules identified by gas chromatography-mass spectrometry (GC-MS) have a high affinity with P. aeruginosa target proteins notably: AHL Synthase LasI (1RO5), virulence factor LasA (3IT7) and transcription protein LasR (6MNV). Similarly, the effect of BS on P. aeruginosa biofilm formation, in vitro, showed strong inhibition. Therefore, our study suggests that the crude biosurfactant from B. aerius is an effective anti-Quorum sensing/antibiofilm and antibacterial agent, warranting further investigation to explore its therapeutic applications.

Extracellular Proteins Isolated from L. acidophilus as an Osteomicrobiological Therapeutic Agent to Reduce Pathogenic Biofilm Formation, Regulate Chronic Inflammation, and Augment Bone Formation In Vitro.

Periprosthetic joint infection (PJI) is a challenging complication that can occur following joint replacement surgery. Efficacious strategies to prevent and treat PJI and its recurrence remain elusive. Commensal bacteria within the gut convey beneficial effects through a defense strategy named "colonization resistance" thereby preventing pathogenic infection along the intestinal surface. This blueprint may be applicable to PJI. The aim is to investigate Lactobacillus acidophilus spp. and their isolated extracellular-derived proteins (LaEPs) on PJI-relevant Staphylococcus aureus, methicillin-resistant S. aureus, and Escherichia coli planktonic growth and biofilm formation in vitro. The effect of LaEPs on cultured macrophages and osteogenic, and adipogenic human bone marrow-derived mesenchymal stem cell differentiation is analyzed. Data show electrostatically-induced probiotic-pathogen species co-aggregation and pathogenic growth inhibition together with LaEP-induced biofilm prevention. LaEPs primemacrophages for enhanced microbial phagocytosis via cathepsin K, reduce lipopolysaccharide-induced DNA damage and receptor activator nuclear factor-kappa B ligand expression, and promote a reparative M2 macrophage morphology under chronic inflammatory conditions. LaEPs also significantly augment bone deposition while abating adipogenesis thus holding promise as a potential multimodal therapeutic strategy. Proteomic analyses highlight high abundance of lysyl endopeptidase, and urocanate reductase. Further, in vivo analyses are warranted to elucidate their role in the prevention and treatment of PJIs.

Antibiofilm Activity of Probiotic Strains against Aggregatibacter actinomycetemcomitans

Aggregatibacter actinomycetemcomitans is a significant agent for periodontal disease. It develops biofilms on gingival plaque and promotes chronic pro-inflammatory response to periodontal tissues. As bacterial cells within the biofilm, this pathogen successfully eluded the human immune system by preventing the uptake of biofilm cells by phagocytic cells. Antibiotic-resistant biofilms might harm the environment, increase mortality, and add to the cost of healthcare. Anti-biofilms are necessary to prevent the growth of biofilms. It has been demonstrated that probiotics change how immune system cells produce cytokines. Therefore, the efficacy of five probiotic lactobacillus strains to prevent A. actinomycetemcomitans from growing bacteria and forming biofilms was evaluated. The organisms were incubated in anaerobic conditions at 37°C for a certain period. The antimicrobial test was done using the lawn method and measuring the size of the inhibition zone produced by the probiotic spots for each probiotic strain. Tetracycline antibiotic disc was used as a positive control to compare the size of the inhibition zone. The antibiofilm activity was performed using probiotic strains at their exponential and stationary phases against the exponential phase of A. actinomycetemcomitans. Our finding showed the probiotic lactobacillus could inhibit the growth of A. actinomycetemcomitans. The highest inhibition was demonstrated by L. johnsonii NBRC 13952. Besides, all probiotic lactobacillus used for this study significantly (p<0.05) inhibited the A. actinomycetemcomitans biofilm using both stationary and exponential phases. In conclusion, probiotic lactobacillus might be a potential agent that can be used to counteract the periodontal pathogen biofilm. Further study should be done to elucidate the antibiofilm mechanism, and several trials of the probiotic lactobacilli against multiple species of biofilms might be helpful in evaluating their effectiveness.

ANTIBACTERIAL COMPARISON BETWEEN MANUKA HONEY AND TUALANG HONEY AGAINST PORPHYROMONAS GINGIVALIS BACTERIA.

Introduction: Periodontal disease, namely gingivitis and periodontitis are an inflammatory condition of the periodontal tissue which involves interactions between bacteria, immune response, inflammatory reactions, and environmental factors. The main cause of periodontal disease is the proliferation of oral pathogenic biofilms. The main problems in the treatment of periodontal disease are antibiotic resistance and the side effects of using mouthwash which have increased over the last decades. Review: Manuka honey and tualang honey are popular ingredients and have antibacterial, antifungal, antioxidant, antiseptic and anti-inflammatory properties, which can be used as alternative choices. The purpose of this paper is to conduct an integrative literature study on manuka honey and tualang honey against the periodontal pathogenic bacteria, namely Porphyromonas gingivalis. The material analyzed was the antibacterial properties of manuka honey and tualang honey by comparing them based on the inhibition zone, MIC and MBC values. Conclusion: Manuka honey and tualang honey have antibacterial potential against Porphyromonas gingivalis, but manuka honey is more effective in inhibiting Porphyromonas gingivalis compared to tualang honey. Manuka honey and Tualang honey can be an alternative to avoid antibiotic resistance.

Synergistic D-Amino Acids Based Antimicrobial Cocktails Formulated via High-Throughput Screening and Machine Learning.

Antimicrobial resistance (AMR) from pathogenic bacterial biofilms has become a global health issue while developing novel antimicrobials is inefficient and costly. Combining existing multiple drugs with enhanced efficacy and/or reduced toxicity may be a promising approach to treat AMR. D-amino acids mixtures coupled with antibiotics can provide new therapies for drug-resistance infection with reduced toxicity by lower drug dosage requirements. However, iterative trial-and-error experiments are not tenable to prioritize credible drug formulations, owing to the extremely large number of possible combinations. Herein, a new avenue is provide to accelerate the exploration of desirable antimicrobial formulations via high-throughput screening and machine learning optimization. Such an intelligent method can navigate the large search space and rapidly identify the D-amino acid mixtures with the highest anti-biofilm efficiency and also the synergisms between D-amino acid mixtures and antibiotics. The optimized drug cocktails exhibit high antimicrobial efficacy while remaining non-toxic, which is demonstrated not only from in vitro assessments but also the first in vivo study using a lung infection mouse model.

How Can Imbalance in Oral Microbiota and Immune Response Lead to Dental Implant Problems?

Dental implantology is one of the most dynamically developing fields of dentistry, which, despite developing clinical knowledge and new technologies, is still associated with many complications that may lead to the loss of the implant or the development of the disease, including peri-implantitis. One of the reasons for this condition may be the fact that dental implants cannot yield a proper osseointegration process due to the development of oral microbiota dysbiosis and the accompanying inflammation caused by immunological imbalance. This study aims to present current knowledge as to the impact of oral microflora dysbiosis and deregulation of the immune system on the course of failures observed in dental implantology. Evidence points to a strong correlation between these biological disturbances and implant complications, often stemming from improper osseointegration, pathogenic biofilms on implants, as well as an exacerbated inflammatory response. Technological enhancements in implant design may mitigate pathogen colonization and inflammation, underscoring implant success rates.

Multispecies Bacterial Biofilms and Their Evaluation Using Bioreactors.

Pathogenic biofilm formation within food processing industries raises a serious public health and safety concern, and places burdens on the economy. Biofilm formation on equipment surfaces is a rather complex phenomenon, wherein multiple steps are involved in bacterial biofilm formation. In this review we discuss the stages of biofilm formation, the existing literature on the impact of surface properties and shear stress on biofilms, types of bioreactors, and antimicrobial coatings. The review underscores the significance of prioritizing biofilm prevention strategies as a first line of defense, followed by control measures. Utilizing specific biofilm eradication strategies as opposed to a uniform approach is crucial because biofilms exhibit different behavioral outcomes even amongst the same species when the environmental conditions change. This review is geared towards biofilm researchers and food safety experts, and seeks to derive insights into the scope of biofilm formation, prevention, and control. The use of suitable bioreactors is paramount to understanding the mechanisms of biofilm formation. The findings provide useful information to researchers involved in bioreactor selection for biofilm investigation, and food processors in surfaces with novel antimicrobial coatings, which provide minimal bacterial attachment.

Pathogenic Biofilm Removal Potential of Wild-Type Lacticaseibacillus rhamnosus Strains.

The emergence of antimicrobial resistance remains one of the greatest public health concerns. Biofilm formation has been postulated as a mechanism of microbial pathogens to resist antimicrobial agents. Lactic Acid Bacteria (LAB) and their metabolites have been proposed to combat bacterial biofilms due to their antimicrobial activity. In this vein, the aim of the present study was to investigate the biofilm removal potential of cell-free supernatants (CFSs) of five wild-type Lacticaseibacillus rhamnosus strains, isolated from Greek natural products, in comparison to the commercially available L. rhamnosus GG strain, against biofilms formed by common foodborne pathogens (Salmonella Enteritidis, Salmonella Typhimurium, Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus). The biofilm removal activity of LAB was assessed on a two-day-old mature biofilm using a microtiter plate-based procedure. Both non-neutralized and neutralized CFSs removed biofilms in a concentration-dependent manner. The biofilm removal activity of the non-neutralized CFSs was significantly higher compared to the neutralized CFSs, as expected, with ranges of 60-89% and 30-80%, respectively. The biofilm removal efficiency of L. rhamnosus OLXAL-3 was significantly higher among the wild-type L. rhamnosus strains tested (20-100% v/v). In conclusion, our results suggest the great potential of the application of wild-type L. rhamnosus strain' CFSs as effective natural agents against pathogenic bacterial biofilms.

Antimicrobial effects and metabolomics analysis of cell-free supernatant produced by Pediococcus acidilactici LWX 401 isolated from Yunnan traditional pickles

Foodborne pathogens pose a significant risk to human health via the food chain. Here, we evaluated the antibacterial effects of cell-free supernatant (CFS) of Pediococcus acidilactici (P. acidilactici) LWX 401 isolated from food-grade Chinese traditional pickles and found that it exhibited broad antibacterial activity against multidrug-resistant gram-negative Escherichia coli (E. coli) O157:H7 and yogurt-derived gram-positive Staphylococcus aureus (S. aureus), with inhibition zone sizes of 23.10 ± 0.80 and 20.53 ± 0.07 mm, respectively (all P < 0.001 compared with the controls). Moreover, the CFS exhibited strong thermostability and pH tolerance and was capable of inhibiting the formation of biofilms of these foodborne pathogens. Notably, the LWX 401 CFS inhibited both E. coli O157:H7 and S. aureus contamination in milk samples under different storage temperatures (4 °C, 25 °C, and 35 °C), with considerable bacterial reduction by 1–7 log CFU/mL compared with untreated controls. Additionally, the potential antibacterial metabolites (VIP >1, adjusted P < 0.05, and fold-change >2; n = 56) were identified in the LWX 401 CFS by UHPLC-QE-MS metabolomic analysis, and these metabolites were mostly lipids (25.73%) and organic acids (23.30%). Our results provide insights for the development of bio-preservatives against foodborne pathogens in the milk industry.

Culture Shock: An Investigation into the Tolerance of Pathogenic Biofilms to Antiseptics in Environments Resembling the Chronic Wound Milieu.

Credible assessment methods must be applied to evaluate antiseptics' in vitro activity reliably. Studies indicate that the medium for biofilm culturing should resemble the conditions present at the site of infection. We cultured S. aureus, S. epidermidis, P. aeruginosa, C. albicans, and E. coli biofilms in IVWM (In Vitro Wound Milieu)-the medium reflecting wound milieu-and were compared to the ones cultured in the laboratory microbiological Mueller-Hinton (MH) medium. We analyzed and compared crucial biofilm characteristics and treated microbes with polyhexamethylene biguanide hydrochloride (PHMB), povidone-iodine (PVP-I), and super-oxidized solution with hypochlorites (SOHs). Biofilm biomass of S. aureus and S. epidermidis was higher in IVWM than in MH medium. Microbes cultured in IVWM exhibited greater metabolic activity and thickness than in MH medium. Biofilm of the majority of microbial species was more resistant to PHMB and PVP-I in the IVWM than in the MH medium. P. aeruginosa displayed a two-fold lower MBEC value of PHMB in the IVWM than in the MH medium. PHMB was more effective in the IVWM than in the MH medium against S. aureus biofilm cultured on a biocellulose carrier (instead of polystyrene). The applied improvement of the standard in vitro methodology allows us to predict the effects of treatment of non-healing wounds with specific antiseptics.

Magnetic‐based photosensitizer to improve the efficiency of antimicrobial photodynamic therapy against mature dental caries‐related biofilms

AbstractAntimicrobial photodynamic therapy (aPDT) shows promise in eliminating oral pathogens without inducing microbial resistance. Yet, it faces limited biofilm penetration by the photosensitizer, which hinders its efficacy against mature, thick biofilms. This study assesses the effectiveness of the MagTBO (magnetic nanoparticles and toluidine‐blue ortho) nanoplatform against mature Streptococcus mutans biofilms associated with dental caries. The study employs constant‐depth film fermenter (CDFF) models, known as “artificial mouth,” to replicate caries processes and allow biofilm growth over teeth. This method enables the evaluation of biofilm‐induced mineral loss under cariogenic challenge over 5 and 10 days. The study shows that MagTBO improves aPDT's effectiveness against highly mature and complex biofilms over 5 and 10 days. However, the biofilm reduction unaffected the mineral content in the underlying dentin. This presents a promising approach for clinical aPDT protocols. However, it is crucial to acknowledge that these findings are based on in vitro studies and may necessitate further clinical confirmation. In summary, our data indicate that magnetic‐based photosensitizers enhance the modulation of pathogenic oral biofilms by aPDT, offering potential advancements in clinical aPDT protocols.

Mucus-Permeable Sonodynamic Therapy Mediated Amphotericin B-Loaded PEGylated PLGA Nanoparticles Enable Eradication of Candida albicans Biofilm.

Candida albicans (C. albicans) forms pathogenic biofilms, and the dense mucus layer secreted by the epithelium is a major barrier to the traditional antibiotic treatment of mucosa-associated C. albicans infections. Herein, we report a novel anti-biofilm strategy of mucus-permeable sonodynamic therapy (mp-SDT) based on ultrasound (US)-mediated amphotericin B-loaded PEGylated PLGA nanoparticles (AmB-NPs) to overcome mucus barrier and enable the eradication of C. albicans biofilm. AmB-NPs were fabricated using ultrasonic double emulsion method, and their physicochemical and sonodynamic properties were determined. The mucus and biofilm permeability of US-mediated AmB-NPs were further investigated. Moreover, the anti-biofilm effect of US-mediated AmB-NPs treatment was thoroughly evaluated on mucus barrier abiotic biofilm, epithelium-associated biotic biofilm, and C. albicans-induced rabbit vaginal biofilms model. In addition, the ultrastructure and secreted cytokines of epithelial cells and the polarization of macrophages were analyzed to investigate the regulation of local cellular immune function by US-mediated AmB-NPs treatment. Polymeric AmB-NPs display excellent sonodynamic performance with massive singlet oxygen (1O2) generation. US-mediated AmB-NPs could rapidly transport through mucus and promote permeability in biofilms, which exhibited excellent eradicating ability to C. albicans biofilms. Furthermore, in the vaginal epithelial cells (VECs)-associated C. albicans biofilm model, the mp-SDT scheme showed the strongest biofilm eradication effect, with up to 98% biofilm re-formation inhibition rate, improved the ultrastructural damage, promoted local immune defense enhancement of VECs, and regulated the polarization of macrophages to the M1 phenotype to enhance macrophage-associated antifungal immune responses. In addition, mp-SDT treatment exhibited excellent therapeutic efficacy against C. albicans-induced rabbit vaginitis, promoted the recovery of mucosal epithelial ultrastructure, and contributed to the reshaping of a healthier vaginal microbiome. The synergistic anti-biofilm strategies of mp-SDT effectively eradicated C. albicans biofilm and simultaneously regulated local antifungal immunity enhancement, which may provide a new approach to treat refractory drug-resistant biofilm-associated mucosal candidiasis.

The Identification of Selective Pathogenic Microbial Community Biofilms in Different Distribution Pipeline Materials and Their Disinfection Kinetics

Biofilms in water distribution lines strongly affect water safety as they are the main carriers of pathogens. The current study investigated the biofilm formation and identification of selected pathogens in different distribution pipeline materials and their disinfection method in an annular reactor (AR). Initially, the quality of the flowing water from each pipeline material was analyzed, i.e., pH, TDS, EC, turbidity, and salinity; then, the biofilm formation was monitored for each material, i.e., ABS, PC, PVC, PP, and HDPE. Further, the disinfection kinetics of biofilm at different chlorine doses, i.e., 0.5, 1.0, 1.5, and 2.0 mg/L, was investigated. The selected pathogens, i.e., E. coli, Pseudomonas, Shigella, Salmonella sp., and Vibrio sp. were identified in biofilms formed in different pipeline materials. The disinfection kinetics results showed that a chlorine dose of 2.0 mg/L was the most effective in disinfecting selected pathogens. Following the disinfection kinetics, it was observed that Salmonella sp. was disinfected within 7 days, whereas other pathogenic biofilms were disinfected within 14 days. The efficacy of chlorine disinfection was affected by the types of pipeline materials. The study outcomes could provide insights into biofilms’ disinfection method and the selection of suitable pipeline materials to ensure drinking water safety.

Enhancing biofilm penetration and antibiofilm efficacy with protein nanocarriers against pathogenic biofilms

Nanocarriers play an important role in enhancing the efficacy of antibiotics against biofilms by improving their penetration and prolonging retention in pathogenic biofilms. Herein, the multifunctional nanocarriers including nanospheres (NS) and nanotubes (NT) with a high biocompatibility and biodegradability were prepared through self-assembly of partially hydrolyzed α-lactalbumin. The effects of these two different shaped nanocarriers on the delivery of antibiotics for biofilm treatment were examined by conducting in vitro antibiofilm experiment and in vivo infected wound model. The strong affinity of NS and NT for the bacterial surface allows antibiotics to be concentrated in the bacteria. Notably, the high permeability of NT into biofilms facilitates deeper penetration and the easier diffusion of loaded antibiotics within the biofilm. Furthermore, the acidic biofilm environment triggers the release of antibiotics from the NT, resulting in the accumulation of high local antibiotic concentrations. Therefore, NT could efficiently clean and inhibit the biofilm formation while also destroying the mature biofilms. In a S. aureus infected wound animal model, treatment with antibiotic-loaded NT demonstrated accelerated healing of S. aureus infected wounds when compared to free antibiotic treatment. These findings indicate that NT nanocarrier strategy is promising for treating bacterial biofilm infections, offering the potential for lower antibiotics dosages and preventing the overuse of antibiotics.

The Role of the Insulin/Glucose Ratio in the Regulation of Pathogen Biofilm Formation.

A variety of Gram-positive and Gram-negative bacteria were grown in peptone (1%) yeast nitrogen base broth overnight in 96-well plates with various concentrations of glucose and insulin. Biofilm formation was determined by the crystal violet staining procedure. Expression of insulin binding was determined by fluorescent microscopy (FITC-insulin). Controls were buffer alone, insulin alone, and glucose alone. Overall, maximal biofilm levels were measured at 220 mg/dL of glucose, regardless of insulin concentration (10, 100, 200 µU/mL) of the organism tested. In general, insulin with glucose over the range of 160-180 mg/dL exhibited a pattern of biofilm suppression. However, either above or below this range, the presence of insulin in combination with glucose significantly modulated (increase or decrease) biofilm formation in a microbe-specific pattern. This modulation appears for some organisms to be reflective of the glucose-regulated intrinsic expression of bacterial insulin receptor expression. Insulin at physiologic levels (normal and hyperinsulinemic) in combination with glucose can affect biofilm formation in a concentration-specific and microbe-specific manner. These findings may provide insight into the importance of co-regulation of the insulin/glucose ratio in patient management.

The Effect of Ficin Immobilized on Carboxymethyl Chitosan on Biofilms of Oral Pathogens.

In the last decade, Ficin, a proteolytic enzyme extracted from the latex sap of the wild fig tree, has been widely investigated as a promising tool for the treatment of microbial biofilms, wound healing, and oral care. Here we report the antibiofilm properties of the enzyme immobilized on soluble carboxymethyl chitosan (CMCh) and CMCh itself. Ficin was immobilized on CMCh with molecular weights of either 200, 350 or 600 kDa. Among them, the carrier with a molecular weight of 200 kDa bound the maximum amount of enzyme, binding up to 49% of the total protein compared to 19-32% of the total protein bound to other CMChs. Treatment with pure CMCh led to the destruction of biofilms formed by Streptococcus salivarius, Streptococcus gordonii, Streptococcus mutans, and Candida albicans, while no apparent effect on Staphylococcus aureus was observed. A soluble Ficin was less efficient in the destruction of the biofilms formed by Streptococcus sobrinus and S. gordonii. By contrast, treatment with CMCh200-immobilized Ficin led to a significant reduction of the biofilms of the primary colonizers S. gordonii and S. mutans. In model biofilms obtained by the inoculation of swabs from teeth of healthy volunteers, the destruction of the biofilm by both soluble and immobilized Ficin was observed, although the degree of the destruction varied between artificial plaque samples. Nevertheless, combined treatment of oral Streptococci biofilm by enzyme and chlorhexidine for 3 h led to a significant decrease in the viability of biofilm-embedded cells, compared to solely chlorhexidine application. This suggests that the use of either soluble or immobilized Ficin would allow decreasing the amount and/or concentration of the antiseptics required for oral care or improving the efficiency of oral cavity sanitization.

Platelet Membrane-Enclosed Bioorthogonal Catalysis for Combating Dental Caries.

Platelets have shown promise as a means to combat bacterial infections, fostering the development of innovative therapeutic approaches. However, several challenges persist, including cargo loading issues, limited efficacy against biofilms, and concerns regarding the impact of payloads on the platelet carriers. Here, human platelet membrane vesicles (h-PMVs) encapsulating supramolecular metal catalysts (SMCs) as "nanofactories" to convert prodrugs into antimicrobial compounds within close proximity to bacteria are introduced. Having established the feasibility and effectiveness of the SMCs within h-PMVs, referred to as the PLT-reactor, to activate pro-antibiotic drugs (pro-ciprofloxacin and pro-moxifloxacin) using model organisms (Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923), the investigation is subsequently extended to oral biofilms, with a particular emphasis on Streptococcus mutans 3065. This "bind and kill" strategy demonstrates the potent antimicrobial specificity of the PLT-reactor through localized antibiotic production. h-PMVs play a pivotal role by enabling precise targeting of pathogenic biofilms on natural teeth while minimizing potential hemolytic effects. The finding indicates that platelet membrane-cloaked surfaces exhibit robust, multifaceted, and pathogen-specific binding affinity with excellent biocompatibility, making them a promising alternative to antibody-based therapies for infectious diseases.

ROS generating BODIPY loaded nanoparticles for photodynamic eradication of biofilms.

Bacterial biofilms can pose a serious health risk to humans and are less susceptible to antibiotics and disinfection than planktonic bacteria. Here, a novel method for biofilm eradication based on antimicrobial photodynamic therapy utilizing a nanoparticle in conjunction with a BODIPY derivative as photosensitizer was developed. Reactive oxygen species are generated upon illumination with visible light and lead to a strong, controllable and persistent eradication of both planktonic bacteria and biofilms. One of the biggest challenges in biofilm eradication is the penetration of the antimicrobial agent into the biofilm and its matrix. A biocompatible hydrophilic nanoparticle was utilized as a delivery system for the hydrophobic BODIPY dye and enabled its accumulation within the biofilm. This key feature of delivering the antimicrobial agent to the site of action where it is activated resulted in effective eradication of all tested biofilms. Here, 3 bacterial species that commonly form clinically relevant pathogenic biofilms were selected: Escherichia coli, Staphylococcus aureus and Streptococcus mutans. The development of this antimicrobial photodynamic therapy tool for biofilm eradication takes a promising step towards new methods for the much needed treatment of pathogenic biofilms.