BACKGROUND AND OBJECTIVE

Orthodontic brackets predispose dental biofilm accumulation causing caries and gingivitis. Chlorhexidine is an adjunct to mechanical plaque removal, but has side-effects (tooth staining, bacterial resistance) due to long term use. This study tested the efficacy of Photodynamic Therapy, which produces reactive oxygen species, to reduce Streptococcus mutans in dental biofilm on orthodontic brackets.

A 5-day S. mutans biofilm was grown on forty enamel-bracket specimens. Thirty-nine specimens were randomized to three treatment groups: A. Distilled Water; B. 0.12% Chlorhexidine (CHX); C. Photodynamic Therapy (PDT) using Toluidine Blue O (TBO) as a photosensitizer, activated by red LED (630nm). After treatment, one random specimen from each group was viewed under Environmental Scanning Electron Microscopy (ESEM); the other 12 specimens, biofilms were collected, weighed, and cultured onto BHI agar plates to determine the number of CFU/mg. For baseline evaluation, one clean and one untreated specimens were preserved for ESEM.

Based on Tukey HSD test, group A had the most S. mutans (37.0573 CFU/mg) and was significantly different (p < 0.05) from groups B (0.1712 CFU/mg) and C (1.1193 CFU/mg), where both showed less bacteria than group A. The statistical difference between groups B and C was insignificant. ESEM images showed specimen A covered with more abundant and denser S. mutans biofilm than specimens B and C, with almost similar morphology showing sparse, less dense, and disintegrated biofilm with unclear cellular walls and presence of amorphous masses.

Both Photodynamic Therapy and 0.12% Chlorhexidine showed a significant reduction of S. mutans in dental biofilm on orthodontic brackets. However, there is no significant difference between them in reducing S. mutans CFU/mg. Photodynamic therapy could be an alternative adjunctive tool to mechanical removal of plaque adhered to orthodontic brackets.

BACKGROUND AND OBJECTIVE

Orthodontic brackets predispose dental biofilm accumulation causing caries and gingivitis. Chlorhexidine is an adjunct to mechanical plaque removal, but has side-effects (tooth staining, bacterial resistance) due to long term use. This study tested the efficacy of Photodynamic Therapy, which produces reactive oxygen species, to reduce Streptococcus mutans in dental biofilm on orthodontic brackets.

A 5-day S. mutans biofilm was grown on forty enamel-bracket specimens. Thirty-nine specimens were randomized to three treatment groups: A. Distilled Water; B. 0.12% Chlorhexidine (CHX); C. Photodynamic Therapy (PDT) using Toluidine Blue O (TBO) as a photosensitizer, activated by red LED (630nm). After treatment, one random specimen from each group was viewed under Environmental Scanning Electron Microscopy (ESEM); the other 12 specimens, biofilms were collected, weighed, and cultured onto BHI agar plates to determine the number of CFU/mg. For baseline evaluation, one clean and one untreated specimens were preserved for ESEM.

Based on Tukey HSD test, group A had the most S. mutans (37.0573 CFU/mg) and was significantly different (pCONCLUSION

Both Photodynamic Therapy and 0.12% Chlorhexidine showed a significant reduction of S. mutans in dental biofilm on orthodontic brackets. However, there is no significant difference between them in reducing S. mutans CFU/mg. Photodynamic therapy could be an alternative adjunctive tool to mechanical removal of plaque adhered to orthodontic brackets.

OBJECTIVE: To explore the mechanism of antibiotic delivery system targeting bacterial biofilm with linezolid (LZD) based on ε-poly- L-lysine (ε-PLL) and cyclodextrin (CD) (ε-PLL-CD-LZD), aiming to enhance antibiotic bioavailability, effectively penetrate and disrupt biofilm structures, and thereby improve the treatment of bone and joint infections. METHODS: ε-PLL-CD-LZD was synthesized via chemical methods. The grafting rate of CD was characterized using nuclear magnetic resonance. In vitro biocompatibility was evaluated through live/dead cell staining after co-culturing with mouse embryonic osteoblast precursor cells (MC3T3-E1), human umbilical vein endothelial cells, and mouse embryonic fibroblast cells (3T3-L1). The biofilm-enrichment capacity of ε-PLL-CD-LZD was assessed using Staphylococcus aureus biofilms through enrichment studies. Its biofilm eradication efficacy was investigated via minimum inhibitory concentration (MIC) determination, scanning electron microscopy, and live/dead bacterial staining. A bone and joint infection model in male Sprague-Dawley rats was established to validate the antibacterial effects of ε-PLL-CD-LZD. RESULTS: In ε-PLL-CD-LZD, the average grafting rate of CD reached 9.88%. The cell viability exceeded 90% after co-culturing with three types cells. The strong biofilm enrichment capability was observed with a MIC of 2 mg/L. Scanning electron microscopy observations revealed the effective disruption of biofilm structure, indicating potent biofilm eradication capacity. In vivo rat experiments demonstrated that ε-PLL-CD-LZD significantly reduced bacterial load and infection positivity rate at the lesion site ( P<0.05). CONCLUSION The ε-PLL-CD antibiotic delivery system provides a treatment strategy for bone and joint infections with high clinical translational significance. By effectively enhancing antibiotic bioavailability, penetrating, and disrupting biofilms, it demonstrated significant anti-infection effects in animal models.
Biofilms/drug effects* ; Animals ; Anti-Bacterial Agents/pharmacology* ; Polylysine/chemistry* ; Cyclodextrins/administration & dosage* ; Humans ; Linezolid/pharmacology* ; Staphylococcus aureus/physiology* ; Rats, Sprague-Dawley ; Mice ; Rats ; Male ; Drug Delivery Systems ; Staphylococcal Infections/drug therapy* ; Microbial Sensitivity Tests ; Human Umbilical Vein Endothelial Cells ; Osteoblasts/cytology*

OBJECTIVE: Peritoneal dialysis(PD)-associated peritonitis is a common and major complication of PD and the most common cause of technical failure of PD. The presence of bacterial biofilm may be an important factor leading to refractory or recurrence of peritonitis. To investigate the formation and characteristics of bacterial biofilms on PD catheters after peritonitis-associated catheter removal. METHODS: The patients with maintenance PD who were regularly followed up in the Peking University People' s Hospital from June 2007 to January 2022 were retrospectively analyzed. The patients who withdrew from PD because of peritonitis and removed the PD catheter in our hospital and underwent the scanning electron microscope examination of the catheter were selected. The general information of the patients, the electron microscope results of the PD catheter and the bacterial culture results of the PD fluid were summarized. RESULTS: (1) A total of 18 patients were included, 11 were female (accounting for 61.1%). The average age of the patients was (59.1±11.5) years, and the average duration of dialysis was (80.1±47.4) months. Primary kidney diseases were predominantly chronic glomerulonephritis (55.6%), followed by diabetic nephropathy (27.8%), and others (16.6%). The reasons for catheters removal in 18 patients were refractory peritonitis in 11 cases, recurrent peritonitis in 5 cases, and fungal peritonitis in 2 cases. (2) 16 of the 18 patients (88.9%) had catheter bacterial biofilm, and the bacterial biofilm forms were all cocci. Some were arranged in grape-like shapes, and their diameters ranged from about 500 nm to 1 000 nm. The bacterial culture results of peritoneal dialysis fluid showed that the three most common pathogens were Escherichia coli, methicillin-sensitive Staphylococcus aureus (MSSA), and Staphylococcus epidermidis. (3) Among the 18 patients enrolled, 13 patients (72.2%) had peritonitis in the past. The causative bacteria of peritonitis in 9 patients were cocci, including coagulase-negative Staphylococci (Staphylococcus suis, Staphylococcus surface, Staphylococcus xylosus, Staphylococcus warneri), Staphylococcus aureus, Streptococcus (Streptococcus salivarius and Aerococus viridans). CONCLUSION Bacterial biofilm formation on the inner surface of PD catheter is common in peritonitis-associated catheter removal patients. Not all PD catheters removed due to peritonitis have bacterial biofilms. Bacterial biofilms and peritonitis pathogens may not be consistent.
Humans ; Biofilms/growth & development* ; Peritonitis/etiology* ; Peritoneal Dialysis/instrumentation* ; Middle Aged ; Female ; Male ; Retrospective Studies ; Catheters, Indwelling/microbiology* ; Device Removal ; Catheter-Related Infections/microbiology* ; Aged ; Adult

OBJECTIVE: To map the potent antifungal properties of the medicinal plant Vitex negundo, in vitro and in silico studies were performed to decipher the pharmacokinetics and ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) properties of their phytoconstituents. METHODS: With the PASS (Prediction of Activity Spectra for Substances) prediction tool, many parameters of V. negundo phenolics were examined, including drug-likeness, bioavailability, antifungal activity, and anti-biofilm activity. Moreover, ADMET parameters were also determined. RESULTS: Eighteen phenolic compounds from V. negundo with significant antifungal activity against Candida species (human fungal pathogens) were detected. The antioxidant activity, inhibition percentage, and minimum inhibitory concentration value of V. negundo phenolic extracts indicate it as an effective antifungal agent for the treatment of candidiasis caused by the fungal pathogen Candida albicans. Many phenolic compounds showed a significantly high efficiency against Candida's planktonic cells and biofilm condition. CONCLUSIONS The phenolics fraction of V. negundo has potent antifungal activities, however, some more pre-clinical studies are a matter of future research to further investigate V. negundo phenolic compound as a potential new antifungal arsenal.
Candida albicans/physiology* ; Vitex/chemistry* ; Antifungal Agents/chemistry* ; Microbial Sensitivity Tests ; Biofilms/drug effects* ; Phenols/pharmacokinetics* ; Plant Extracts/chemistry* ; Antioxidants/pharmacology* ; Phytochemicals/pharmacology* ; Humans

OBJECTIVE: To investigate the regulatory effects of two traditional mineral medicines (TMMs), Gypsum Fibrosum (Shigao, GF) and Terra Flava Usta (Zaoxintu, TFU), on gut-beneficial bacteria in mice, and preliminarily explore their mechanisms of action. METHODS: Mice were randomly divided into 3 groups (n=10 per group): the control group (standard diet), the GF group (diet supplemented with 2% GF), and the TFU group (diet supplemented with 2% TFU). After 4-week intervention, 16S rRNA gene sequencing was used to analyze the changes in the gut microbiota (GM). Scanning electron microscopy, in combination with coumarin A tetramethyl rhodamine conjugate and Hoechst stainings, was used to observe the bacteria and biofilm formation. RESULTS: Principal coordinate analysis revealed that GF and TFU significantly altered the GM composition in mice. Further analysis revealed that GF and TFU affected different types of gut bacteria, suggesting that different TMMs may selectively modulate specific bacterial populations. For certain bacteria, such as Faecalibaculum and Ileibacterium, both GF and TFU exhibited growth-promoting effects, implying that they may be sensitive to TMMs and that different TMMs can increase their abundance through their respective mechanisms. Notably, Lactobacillus reuteri, a widely recognized and used probiotic, was significantly enriched in the GF group. Random forest analysis identified Ileibacterium valens as a potential indicator bacterium for TMMs' impact on GM. Further mechanistic studies showed that gut bacteria formed biofilm structures on the TFU surface. CONCLUSIONS This study provides new insights into the interaction between TMMs and GM. As safe and effective natural clays, GF and TFU hold promise as potential candidates for prebiotic development.
Animals ; Gastrointestinal Microbiome/drug effects* ; Bacteria/growth & development* ; Mice ; Biofilms/drug effects* ; Male ; RNA, Ribosomal, 16S/genetics*

Chronic rhinosinusitis with nasal polyps（CRSwNP） represents a prevalent inflammatory disorder, which is often accompanied by nasal congestion, mucopurulent discharge, olfactory dysfunction, dizziness, and headache. Staphylococcus aureus（SA）, a predominant opportunistic pathogen within the sinonasal microenvironment, has been implicated in modulating the pathogenesis and progression of CRSwNP through multifaceted mechanisms. The physiological activities of SA-dependent quorum-sensing system and biofilm in the nasal microenvironment, including interactions with host, fungi, viruses, and other bacteria, as well as the effects of important superantigens secreted by SA on the microenvironment and immune barrier, are briefly reviewed in this article. These insights provide theoretical foundations for elucidating CRSwNP mechanisms and advancing clinical therapeutic strategies.
Humans ; Sinusitis/microbiology* ; Nasal Polyps/microbiology* ; Staphylococcus aureus ; Chronic Disease ; Rhinitis/microbiology* ; Staphylococcal Infections/microbiology* ; Quorum Sensing ; Biofilms ; Rhinosinusitis

OBJECTIVES: To explore the efficacy of low-intensity pulsed ultrasound (LIPUS) combined with nystatin for treatment of vaginal Candida albicans biofilm infection. METHODS: In vitro cultured Candida albicans biofilm were treated with LIPUS, nystatin, or both, and the minimum inhibitory concentration (MIC) of nystatin was determined. Crystal violet staining, confocal laser microscopy (CLSM) and scanning electron microscopy were used to quantify the biofilm and observe the activity and morphological changes of the biofilms; DCFH-DA was used to detect the changes in reactive oxygen species (ROS). Twenty female New Zealand White rabbits with vaginal inoculation of Candida albicans biofilm were randomized into 4 groups for treatment with normal saline, LIPUS, nystatin, or both LIPUS and nystatin. The changes in vulvar symptoms of the rabbits were observed, and the histopathological and ultrastructural changes of the vagina before and after treatment were observed using HE staining and transmission electron microscopy. RESULTS: In the combined treatment group, the MIC₅₀ and MIC₈₀ of nystatin in Candida albicans biofilms were both reduced by 50% compared with those in nystatin group, and the biofilm clearance rate increased by 26% and 68% compared with nystatin and LIPUS groups, respectively. Compared with nystatin and LIPUS treatment alone, the combined treatment produced stronger effects for inhibiting biofilm activity, causing structural disruption and promoting ROS production. In the rabbit models, the combined treatment more effectively improved vulvar symptoms and inflammatory infiltration, reduced residual vaginal hyphae/strains, and improved ultrastructure of the vaginal epithelium than LIPUS and nystatin treatment alone. CONCLUSIONS LIPUS combined with nystatin produces a significant synergistic antifungal effect against Candida albicans biofilm both in vitro and in vivo.
Animals ; Rabbits ; Female ; Biofilms/drug effects* ; Candida albicans/physiology* ; Nystatin/therapeutic use* ; Candidiasis, Vulvovaginal/microbiology* ; Ultrasonic Waves ; Antifungal Agents/therapeutic use* ; Vagina/microbiology* ; Ultrasonic Therapy ; Microbial Sensitivity Tests ; Combined Modality Therapy

Dental implants have restored masticatory function to over 100 000 000 individuals, yet almost 1 000 000 implants fail each year due to peri-implantitis, a disease triggered by peri-implant microbial dysbiosis. Our ability to prevent and treat peri-implantitis is hampered by a paucity of knowledge of how these biomes are acquired and the factors that engender normobiosis. Therefore, we combined a 3-month interventional study of 15 systemically and periodontally healthy adults with whole genome sequencing, fine-scale enumeration and graph theoretics to interrogate colonization dynamics in the pristine peri-implant sulcus. We discovered that colonization trajectories of implants differ substantially from adjoining teeth in acquisition of new members and development of functional synergies. Source-tracking algorithms revealed that this niche is initially seeded by bacteria trapped within the coverscrew chamber during implant placement. These pioneer species stably colonize the microbiome and exert a sustained influence on the ecosystem by serving as anchors of influential hubs and by providing functions that enable cell replication and biofilm maturation. Unlike the periodontal microbiome, recruitment of new members to the peri-implant community occurs on nepotistic principles. Maturation is accompanied by a progressive increase in anaerobiosis, however, the predominant functionalities are oxygen-dependent over the 12-weeks. The peri-implant community is easily perturbed following crown placement, but demonstrates remarkable resilience; returning to pre-perturbation states within three weeks. This study highlights important differences in the development of the periodontal and peri-implant ecosystems, and signposts the importance of placing implants in periodontally healthy individuals or following the successful resolution of periodontal disease.
Humans ; Dental Implants/microbiology* ; Microbiota ; Male ; Adult ; Female ; Biofilms ; Middle Aged ; Peri-Implantitis/microbiology*

The caries-preventive effects of arginine have been attributed to its impact on biofilm composition and pH. Recent in vitro studies suggest that arginine also affects the production of biofilm matrix components that contribute to virulence, but this mechanism has not been investigated clinically. This randomized, placebo-controlled, triple-blind, split-mouth in situ trial assessed arginine's impact on the microbial composition, matrix architecture, and microscale pH of biofilms from caries-active patients (N = 10). We also examined whether individual differences in the pH response to arginine were related to biofilm composition and matrix structure. Biofilms were grown for four days on carriers attached to intraoral splints. Three times daily, the biofilms were treated extraorally with sucrose (5 min), followed by arginine or placebo (30 min), in a split-mouth design. After growth, the microscale biofilm pH response to sucrose was monitored by pH ratiometry. Microbial biofilm composition and carbohydrate matrix architecture were analyzed by 16S rRNA gene sequencing and fluorescence lectin-binding analysis, respectively. Arginine treatment significantly mitigated sucrose-induced pH drops, reduced total carbohydrate matrix production, and altered the spatial distribution of fucose- and galactose-containing carbohydrates. Both arginine- and placebo-treated biofilms were dominated by streptococci and Veillonella spp. Paired analyses showed a significant reduction in mitis/oralis group streptococci and a non-significant increase in several arginine metabolizers in arginine-treated biofilms. Individual pH responses were not significantly associated with the abundance of specific bacterial taxa or carbohydrate matrix components. In conclusion, arginine reduced the virulence of biofilms from caries-active patients through multiple mechanisms, including suppressing matrix carbohydrate production.
Biofilms/drug effects* ; Humans ; Arginine/pharmacology* ; Hydrogen-Ion Concentration ; Dental Caries/prevention & control* ; Male ; Female ; Adult ; Double-Blind Method ; Sucrose/pharmacology*