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A novel tedizolid phosphate (TZP) nanoparticle (NP)-loaded buccal film formulation was developed for the treatment of buccal wounds infected with S. aureus. TZP-loaded chitosan NPs were produced and characterized to prepare this composite system. The optimum NP formulation was then loaded into mucoadhesive buccal films. The antibacterial effects of the obtained buccal films were evaluated by in vitro and in vivo studies. The optimum TZP-NP formulation (F8) had a particle size of 177.40 ± 2.97 nm and PDI and ZP values were 0.437 ± 0.002 and 33.9 ± 0.5, respectively. In antibacterial efficacy tests, the optimum NP containing buccal film formulation was used, which released approximately 90 % of TZP within 5 h. TZP-NP-loaded buccal films achieved a 3 log 10 reduction in S. aureus within just 3 h. It was also administered to Wistar albino rats with S. aureus-infected buccal wounds. As a result of in vivo studies, a significant decrease in the number of S. aureus was detected in wound samples treated with TZP-NP-loaded buccal films. In addition, a complete inhibition of growth was observed on the fifth day of the film application. The current work suggested that the TZP-NP-loaded composite films could be promising candidates for effective and long-acting antibacterial treatment of buccal wounds., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Purpose: This study aimed to quantify Aggregatibacter actinomycetemcomitans (A.a) and Porphyromonas gingivalis (P.g) from the mouth of head and neck irradiated and cancer-free patients., Methods: Information such as age, presence of tongue coating, salivary flow, and biofilm were collected from head and neck irradiated patients (Group 1) and compared the results with a group of cancer-free individuals (Group 2). The presence of tongue coating was clinically examined. Sialometry was performed through a stimulating technique by chewing paraffin. Microbiological samples were collected from buccal and labial mucosa and tongue dorsum. Subsequently, the samples were processed and analyzed by qPCR to detect the presence and quantify the bacteria., Results: There was a statistical difference in the quantity of bacteria among the 24 individuals in Group 1 (A.a, 2817 ± 8718; P.g, 3145 ± 11297) and 26 individuals in Group 2 (A.a, 133996 ± 398545; P.g, 60 ± 195) regarding tongue coating (Group 1, A.a 2194.6 ± 4641.5; Group 2, A.a 92767.8 ± 333385.7) and salivary volume (Group 1, 0.69 mL; Group 2, 3.09 mL). The linear regression analysis found that the variable group was the main responsible for the difference in the quantity of periodontal pathogens (p-value < 0.001). There was no statistical difference in the amount of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis between totally edentulous and partially edentulous (with 12 or fewer teeth) patients., Conclusion: Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis were present in significant amounts in patients of both groups, with a greater quantity in cancer-free individuals., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Probiotic strains offer a novel and potentially effective approach to treat oral candidiasis. Buccal mucoadhesive films have attracted considerable attention in recent years due to their unique ability to adhere and persist on the oral mucosa, while gradually releasing their encapsulated drug content. Therefore, the aim of the study was to develop mucoadhesive films containing probiotic extract for treatment of oral candidiasis. Mucoadhesive films were fabricated with hydrophilic polymers, such as polyvinyl alcohol (PVA) and hydroxy propyl methyl cellulose (HPMC). Then, films were evaluated regarding their thickness, pH, tensile strength and elongation, swelling, in vitro release and antifungal activity. The type of polymer used had an impact on the mechanical properties, swelling and release of the films. Films prepared using PVA showed significantly higher tensile strength and elongation at break values compared to those prepared using HPMC. However, swelling index increased with enhancing HPMC concentration in the films. The release of probiotic extract from the film prepared with HPMC occurred slowly. Based on these results, films containing 54 % HPMC and 26 % PVA were selected as optimal formulation. Moreover, it was found that optimal film containing probiotic extract could inhibit the growth of Candida albicans. Regarding to the obtained results, probiotic oral adhesive mucoadhesive films can be considered as a promising alternative to traditional methods in the treatment of candidiasis., Competing Interests: Declaration of competing interest The authors disclose no potential conflicts of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Determining the source of body fluids is crucial in forensic investigations, as it provides valuable information about suspects and the nature of the crime. Microbial markers that trace the source of tissues and body fluids based on site specificity and temporal stability are often used effectively for this purpose. In this study, a multiplex system comprising seven microbial markers (Finegoldia magna, Corynebacterium tuberculostearicum, Cutibacterium acnes, Haemophilus parainfluenzae, Streptococcus oralis, Prevotella melaninogenica and Faecalibacterium prausnitzii) was developed to distinguish between skin, saliva, and feces samples. Based on these markers, the system produces electropherograms that are specific for each sample type. We collected 492 samples from six different skin sites (palm, antecubital crease, inguinal crease, cheek, upper back, and toe web space), the buccal mucosa, and stool were collected to further test the system. Beta diversity analysis revealed distinct clustering among the three sample groups. Additionally, skin microenvironment cluster analysis was used to identify skin sites accurately. This analysis classified skin samples into four distinct microenvironments: dry, moist, oily, and foot. Finally, we established a machine learning prediction model based on random forest regression to identify the skin microenvironment, achieving an overall prediction accuracy of 79 %. The multiplex system developed in this study accurately identifies the sources of body fluids, and the skin microenvironment. These findings offer new insights into the application of microbial markers in forensic science., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The oral microbiome is a critical determinant of health and disease, as interactions between oral microorganisms can influence their physiology and the development or severity of oral infections. Lactobacilli have a widely recognized antagonistic relationship with Candida albicans and may exhibit probiotic properties that limit oral fungal infection. We previously reported that Lactobacillus johnsonii strain MT4, an oral strain isolated from C57BL/6 mice, can induce global changes in the murine oral microbiome and has anti- Candida activity in vitro . To build on this information, we analyzed its abundance on the mouse oral mucosa, tested its impact on the severity and progression of oropharyngeal candidiasis (OPC) in a mouse model, and further explored the mechanism of antifungal activity in vitro . Our findings reveal that L. johnsonii MT4 is a dominant cultivable Lactobacillus in the oral mucosa of C57BL/6 mice. Strain MT4 has chitinase activity against C. albicans , which damages the cell wall and compromises fungal metabolic activity. Oral inoculation with strain MT4 causes a reduction in the Candida -induced rise in the abundance of oral enterococci and oral mucosal damage. This research underscores the potential of L. johnsonii strain MT4 as a novel probiotic agent in the prevention or management of OPC, and it contributes to a better understanding of the role of oral bacterial microbiota role in the pathogenesis of fungal infections., Importance: The interactions between the opportunistic pathogen Candida albicans and resident oral bacteria are particularly crucial in maintaining oral health. Emerging antifungal drug-resistant strains, slow-paced drug discovery, and the risk of side effects can compromise the effectiveness of current treatments available for oropharyngeal candidiasis. This study advances the search for alternative microbiome-targeted therapies in oral fungal infections. We report that Lactobacillus johnsonii strain MT4 prevents the Candida -induced bloom of dysbiotic oral enterococci and reduces oral mucosal lesions in an oropharyngeal candidiasis murine model. We also show that this strain directly compromises the cell wall and reduces fungal metabolic activity, partly due to its chitinase activity., Competing Interests: The authors declare no conflict of interest.

Introduction. Tissue conditioners modified with antifungals are a potential alternative to denture stomatitis (DS) treatment. Gap Statement. Information on tissue response to this treatment before its clinical application is lacking. Aim. This study aimed to evaluate the tissue response of a tissue conditioner modified with antifungals in a rat model of DS. Methodology. After DS induction for 4 days under antibiotic therapy, Wistar rats had their intraoral devices (IODs) relined with the tissue conditioner Softone without (Soft) or with the MICs against Candida albicans of nystatin (Nys) or chlorhexidine (Chx) complexed or not with β-cyclodextrin (Nys:βCD and Chx:βCD). Three controls were included: healthy rats [negative control (Nc)], rats using a sterile IOD [sterile device (Sd)] and rats with DS that did not receive treatment (DS). After 4 days of treatment, the palatal mucosa under the IODs underwent histological processing for morphohistopathological and histometric analyses, morphology of collagen fibres (birefringence), immunohistochemistry for the expression of cell proliferation (proliferating cell nuclear antigen) and cytokine (IL-1β). Results. The Nc and Sd groups were similar ( P >0.05), displaying epithelial and connective tissues without any discernible changes in the parameters assessed. The DS and Soft groups exhibited pronounced epithelial alterations, cell proliferation and expression of the cytokine IL-1β. In groups treated with drug incorporation (Nys, Chx, Nys:βCD and Chx:βCD), all samples demonstrated a reduction in tissue inflammation or complete tissue recovery, with an epithelium compatible with health. For the immunohistochemical parameters, the Chx, Nys:βCD and Chx:βCD groups were comparable with Nc ( P >0.05). Conclusion. The proposed treatment could be promising for DS, as it led to the tissue recovery of the palatal mucosa. Nevertheless, much lower concentrations of complexed antifungals were required to achieve a similar or higher degree of tissue response compared with uncomplexed drugs in a modified tissue conditioner formulation.

Objectives: Acute oral mucosal damage, as well as other inflammatory processes seem to be related to dysbiosis of the oral microbiome. The need to study changes in the oral microbiome led us to hypothesize what type of sample would provide the most representative picture of the entire human oral microbiome., Materials and Methods: An observational, and cross-sectional study was carried out. Six healthy adult participants provided 3 different sample types each, that included saliva, oral rinse and mucosal biopsy tissue. We performed 16S rRNA sequencing of the V3-V4 region of the 18 samples using Illumina MiSeq technology., Results: Participants were 27 ± 6,3 years old. Bacterial alpha diversity was higher in oral rinse samples compared to whole unstimulated saliva and oral mucosa tissue (p = 0,005). However, saliva specimens showed a 56 % relative abundance of identified species followed by a 30 % in oral rinse and only 1 % in tissue samples., Conclusions: This study found differences on oral microbiome composition for each type of sample. Oral rinse should be chosen when higher alpha diversity is needed, whereas whole unstimulated saliva should be more appropriate for larger amount of bacterial DNA., Clinical Relevance: The results obtained demonstrate the importance of a correct choice of the optimal type of oral sample for microbiome studies due to the differences found in its composition., Competing Interests: Declaration of competing interest None, (Copyright © 2024 The Author(s). Published by Elsevier Masson SAS.. All rights reserved.)

Introduction and Aims: Adhesion to buccal epithelial cells (BEC) and denture acrylic surfaces (DAS), germ tube (GT) formation, cell surface hydrophobicity (CSH), and haemolysin production are attributes associated with pathogenicity of Candida. Candida albicans and Candida dubliniensis are allied in causing oral candidosis. Lysozyme and lactoferrin exert antimicrobial activity on a range of oral microorganisms, including Candida. There is no information on the impact of brief exposure to lysozyme and lactoferrin on adhesion-related attributes and haemolysin production of aforementioned oral Candida isolates. Thus, we investigated the impact of lysozyme and lactoferrin on adhesion to BEC and DAS, GT formation, CSH, and haemolysin production of these isolates., Methods: After exposure to lysozyme and lactoferrin for 1 hour, susceptibility to lysozyme and lactoferrin of 20 isolates each of C albicans and C dubliniensis isolates was determined following a 48-hour period of incubation. Candida cell suspensions, obtained from colony-forming units after this period, were assessed for adhesion to BEC and DAS, GT formation, CSH, and haemolysin production using in vitro assays., Results: Exposure to lysozyme and lactoferrin significantly suppressed the ability of C albicans and C dubliniensis isolates to adhere to BEC and DAS, GT formation, CSH, and haemolysin production (P < 0.01 for all virulent attributes tested)., Conclusions: These data provide a tantalising glimpse into the possibility that exposure to either lysozyme or lactoferrin, even for a brief period, would induce a sustainable antifungal effect by suppressing adhesion-related attributes and haemolysin production of these oral Candida species in vitro. Resistance to conventional antifungal agents has been reported in clinical isolates of Candida. The presence of such resistance indicates the need for possible alternative therapies to facilitate the management of oral candidosis. Further research on the pharmacodynamics of lysozyme and lactoferrin and their effects on candidal pathogenic attributes should be fostered, with the vision of developing novel topical antifungal drugs., Competing Interests: Conflict of interest None disclosed., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Ethnopharmacological Relevance: Coptidis rhizoma, first recorded in the "Shen Nong's Herbal Classic", is one of the traditional Chinese medicine (TCM) used to treat infectious diseases, with reputed effectiveness against oropharyngeal candidiasis (OPC). Studies have demonstrated the inhibitory properties of C. rhizoma (CRE) against Candida albicans, yet there is limited information available regarding its treatment mechanism for OPC., Aim of the Study: Our previous research has suggested that CRE can prevent the formation of C. albicans hyphae and their invasion of the oral mucosa, thereby exerting a therapeutic effect on OPC. Nevertheless, the precise therapeutic mechanisms remain incompletely understood. Previous studies have revealed that a receptor for globular heads of C1q (gC1qR), a crucial co-receptor of the epidermal growth factor receptor (EGFR), facilitates the EGFR-mediated internalization of C. albicans. Therefore, this study aims to investigate the potential mechanism of action of CRE and its primary component, berberine (BBR), in treating OPC by exploring their effects on the gC1qR-EGFR co-receptor., Materials and Methods: To identify the chemical components of CRE, we utilized Ultra-high performance liquid chromatography in conjunction with quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS E ), revealing the presence of at least 18 distinct components. To observe the therapeutic effects of CRE on OPC at the animal level, we employed hematoxylin and eosin staining, periodic acid-Schiff staining, scanning electron microscopy, and fungal load detection. Subsequently, we evaluated the anti-inflammatory properties of CRE and its main component, BBR, in treating OPC. This was achieved through enzyme-linked immunosorbent assay (ELISA) both at the animal and cellular levels. Additionally, we assessed the ability of C. albicans to disrupt the epithelial barrier of FaDu cells by studying the protective effects of BBR on the fusion barrier using the transwell assay. To further explore the underlying mechanisms, we analyzed the effects of BBR on the gC1qR-EGFR/extracellular signal-regulated kinase/c-Fos signaling pathway at the cellular level using qRT-PCR, western blotting, and immunofluorescence. Furthermore, we validated the effects of BBR on the gC1qR-EGFR co-receptor through ELISA, qRT-PCR, and western blotting. Finally, to confirm the outcomes observed at the cellular level, we validated the impact of CRE on the gC1qR-EGFR co-receptor in vivo using qRT-PCR, western blotting, and immunofluorescence. These comprehensive methods allowed us to gain a deeper understanding of the therapeutic mechanisms of CRE and BBR in treating OPC., Results: Our findings indicate that CRE and its primary component, BBR, effectively alleviated the symptoms of OPC by modulating the gC1qR-EGFR co-receptor. The chemical composition of CRE and BBR was accurately identified using UPLC-Q/TOF-MS E . The gC1qR-EGFR co-receptor plays a crucial role in regulating downstream signaling pathways, emerging as a potential therapeutic target for OPC treatment. Through both in vitro and in vivo experiments, we explored the therapeutic potential of CRE and BBR in OPC. Additionally, we employed overexpression and silencing techniques to confirm that BBR can indeed influence the gC1qR-EGFR co-receptor and regulate the gC1qR-EGFR/extracellular signal-regulated kinase (ERK)/c-Fos signaling pathway, leading to improved OPC outcomes. Furthermore, the significance of CRE's effect on the gC1qR-EGFR co-receptor was validated in vivo., Conclusion: Our study demonstrates that CRE and its main component, BBR, can effectively alleviate OPC symptoms by targeting the gC1qR-EGFR heterodimer receptor. This discovery offers a promising new therapeutic approach for the treatment of OPC., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Objectives: This systematic review and meta-analysis aimed to evaluate the clinical and mycological effectiveness of mucoadhesives as vehicles for drugs or natural products in the treatment of oral candidiasis., Materials and Methods: The search for articles was carried out in the Medline/PubMed, SCOPUS, EMBASE, Web of Science, Cochrane Library, and SciELO databases before August 2023. We selected the studies, extracted the data, evaluated the study quality, graded the evidence, performed the risk of bias, and carried out meta-analysis., Results: A total of 389 potentially relevant articles were identified, and 11 studies (1869 participants) met the inclusion criteria of the systematic review. The overall risk of bias was considered low. The most common presentation of mucoadhesives was tablets, with miconazole being the most frequently drug used in the delivery system. Mucoadhesives demonstrated comparable efficacy with topical or systemic antifungal agents, with no significant differences between treatments in terms of clinical (RR = 0.907; 95CI = 0.3-1.297; p = 0.591; I 2  = 64.648) or mycological (RR = 0.95; 95CI = 0.667-1.360; p = 0.789; I 2  = 73.271) efficacy., Conclusions: Mucoadhesives may be a suitable alternative to conventional treatments, with the advantage of reducing the frequency of application by up to 5 times and the daily dosage by up to 20 times., (© 2024 Wiley Periodicals LLC.)

Oral microecological imbalance is closely linked to oral mucosal inflammation and is implicated in the development of both local and systemic diseases, including those caused by viral infections. This review examines the critical role of the interleukin (IL)-17/helper T cell 17 (Th17) axis in regulating immune responses within the oral mucosa, focusing on both its protective and pathogenic roles during inflammation. We specifically highlight how the IL-17/Th17 pathway contributes to dysregulated inflammation in the context of respiratory viral infections. Furthermore, this review explores the potential interactions between respiratory viruses and the oral microbiota, emphasizing how alterations in the oral microbiome and increased production of proinflammatory factors may serve as early, non-invasive biomarkers for predicting the severity of respiratory viral infections. These findings provide insights into novel diagnostic approaches and therapeutic strategies aimed at mitigating respiratory disease severity through monitoring and modulating the oral microbiome., Competing Interests: Declaraion of Competing Interest All other authors declare they have no competing interests., (Copyright © 2024 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Background: Microbiomics offers new methods for conducting epidemiological surveys of oral microbiota in large populations. Compared to curette sampling, swab sampling is more convenient and less technically sensitive, making it more suitable for such surveys. To verify the feasibility of using swabs for buccal mucosa sampling in large-scale studies, we collected samples from the buccal mucosa and tooth surfaces of healthy individuals using both swabs and curettes. Microbiomics was employed to analyze and compare microbial abundance and diversity between these two methods., Methods: Four sites were assessed: the buccal mucosa on both sides and the buccal surfaces of the left and right mandibular first molars. Two sampling methods, swab and curette, were used to collect bacterial communities from healthy individuals. Specifically, buccal mucosa samples (n = 10) and tooth surface samples (n = 20) were analyzed using 16 S rDNA gene sequencing. Bacterial signals were detected through fluorescence in situ hybridization (FISH), targeting the bacterial 16 S rDNA gene. Metastats analysis and Wilcoxon test were used., Results: A total of 383 OTUs were detected in the 30 samples, which belonged to 1 kingdom (bacteria), 11 phyla, 23 classes, 40 orders, 75 families, 143 genus, and 312 species. Among them, 223 OTUs were found on both the buccal mucosa and tooth surfaces. The statistics suggest that although there were no significant differences in colony composition, there were differences in the abundance and distribution of colonies on the dental and buccal mucosal surfaces. When detecting oral disease-causing pathogens such as Enterococcus faecalis and Porphyromonas gingivalis, the efficiency of detection is higher when using curette sampling. Compared to right tooth sampling with a curette, the swab sampling group had higher levels of Firmicutes, while Fusobacteria and Bacteroidetes were more prevalent in the curette tissues., Conclusions: In oral health individuals, there is no difference in the bacterial composition of the oral buccal mucosa and the dental surface, differing only in abundance. Thus, the buccal mucosa can act as a substitute for the teeth in epidemiological investigations exploring the bacterial composition of the oral cavity., (© 2024. The Author(s).)

In this research, 3D-printed antifungal buccal films (BFs) were manufactured as a potential alternative to commercially available antifungal oral gels addressing key considerations such as ease of manufacturing, convenience of administration, enhanced drug efficacy and suitability of paediatric patients. The fabrication process involved the use of a semi-solid extrusion method to create BFs from zein-Poly-Vinyl-Pyrrolidone (zein-PVP) polymer blend, which served as a carrier for drug (miconazole) and taste enhancers. After manufacturing, it was determined that the disintegration time for all films was less than 10 min. However, these films are designed to adhere to buccal tissue, ensuring sustained drug release. Approximately 80% of the miconazole was released gradually over 2 h from the zein/PVP matrix of the 3D printed films. Moreover, a detailed physicochemical characterization including spectroscopic and thermal methods was conducted to assess solid state and thermal stability of film constituents. Mucoadhesive properties and mechanical evaluation were also studied, while permeability studies revealed the extent to which film-loaded miconazole permeates through buccal tissue compared to commercially available oral gel formulation. Histological evaluation of the treated tissues was followed. Furthermore, in vitro antifungal activity was assessed for the developed films and the commercial oral gel. Finally, films underwent a two-month drug stability test to ascertain the suitability of the BFs for clinical application. The results demonstrate that 3D-printed films are a promising alternative for local administration of miconazole in the oral cavity., (© 2024. The Author(s), under exclusive licence to American Association of Pharmaceutical Scientists.)

Since the local treatment of oral candidiasis usually requires long-term administration of the antifungal drug, an ideal dosage form should be able to maintain the drug release over an extended period, assuring an adequate concentration at the infection site. In this context, we have considered the possibility of a buccal delivery of miconazole nitrate (MN) by mucoadhesive polymeric matrices. The loading of the antifungal drug in a hydrophilic matrix was made possible by taking advantage of the amphiphilic nature of liposomes (LP). The MN-loaded LP were prepared by a thin film evaporation method followed by extrusion, while solid matrices were obtained by freeze-drying a suspension of the LP in a polymeric solution based on chitosan (CH), sodium hyaluronate (HYA), or hydroxypropyl methylcellulose (HPMC). MN-loaded LP measured 284.7 ± 20.1 nm with homogeneous size distribution, adequate drug encapsulation efficiency (86.0 ± 3.3 %) and positive zeta potential (+47.4 ± 3.3). CH and HYA-based formulations almost completely inhibited C. albicans growth after 24 h, even if the HYA-based one released a higher amount of the drug. The CH-based matrix also provided the best mucoadhesive capacity and therefore represents the most promising candidate for the local treatment of oral candidiasis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Objective: To assess changes in the urinary microbiota after buccal urethroplasty., Methods: At the University of California San Francisco, we enrolled 9 adult males with urethral strictures undergoing buccal urethroplasty where we collected urine and oral swabs intraoperatively and 3 months postoperatively. 16S rRNA sequencing was used to profile the microbiota., Results: At baseline, the mouth contains twice the number of unique bacteria (alpha diversity) and the microbial community is significantly distinct compared to the urinary tract. Despite having a buccal mucosa in the urinary tract after urethroplasty, the number of unique bacteria in the urine remained stable. However, the bacterial community composition and structure significantly changed in the urinary tract with the enrichment of Corynebacterium genus at 3 months post-urethroplasty procedure., Conclusion: In this pilot study, we showed that the alpha diversity in the urinary microbiota did not significantly change despite having a buccal tissue with the capacity to support high bacterial diversity in the urinary tract. To our surprise, the post-urethroplasty urinary microbiota was not a hybrid of baseline oral and urine microbiotas; the changes detected, such as an enrichment of the Corynebacterium genus, were more nuanced yet could profoundly impact surgical outcomes like graft changes and stricture recurrence. Our study not only established the feasibility but also outlined a blueprint for conducting a large-scale study to assess alterations in the urinary microbiome in relation to surgical outcomes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The oral cavity is inhabited by abundant microbes which continuously interact with the host and influence the host's health. Such host-microbe interactions (HMI) are dynamic and complex processes involving e.g. oral tissues, microbial communities and saliva. Due to difficulties in mimicking the in vivo complexity, it is still unclear how exactly HMI influence the transition between healthy status and disease conditions in the oral cavity. As an advanced approach, three-dimensional (3D) organotypic oral tissues (epithelium and mucosa/gingiva) are being increasingly used to study underlying mechanisms. These in vitro models were designed with different complexity depending on the research questions to be answered. In this review, we summarised the existing 3D oral HMI models, comparing designs and readouts, discussing applications as well as future perspectives.

Biofilms, intricate microbial communities entrenched in extracellular polymeric substance (EPS) matrices, pose formidable challenges in infectious disease treatment, especially in the context of interkingdom biofilms prevalent in the oral environment. This study investigates the potential of carvacrol-loaded biodegradable nanoemulsions (NEs) with systematically varied surface charges─cationic guanidinium (GMT-NE) and anionic carboxylate (CMT-NE). Zeta potentials of +25 mV (GMT-NE) and -33 mV (CMT-NE) underscore successful nanoemulsion fabrication (∼250 nm). Fluorescent labeling and dynamic tracking across three dimensions expose GMT-NE's superior diffusion into oral biofilms, yielding a robust antimicrobial effect with 99.99% killing for both streptococcal and Candida species and marked reductions in bacterial cell viability compared to CMT-NE (∼4-log reduction). Oral mucosa tissue cultures affirm the biocompatibility of both NEs with no morphological or structural changes, showcasing their potential for combating intractable biofilm infections in oral environment. This study advances our understanding of NE surface charges and their interactions within interkingdom biofilms, providing insights crucial for addressing complex infections involving bacteria and fungi in the demanding oral context.

Objective: To assess the efficacy of Phyllanthus emblica extract in alleviating halitosis and reducing the inflammatory response to halitosis-related bacteria., Methodology: This investigation, using Phyllanthus emblica fruit extract (PE), involved four aspects. First, we evaluated the effect on growth and aggregation of halitosis-related bacteria, including Fusobacterium nucleatum, Porphyromonas gingivalis, and Solobacterium moorei, using a microdilution assay and scanning electron microscopy. Second, volatile sulfur compound (VSC) levels were measured on individuals with halitosis in randomized short-term (26 participants) and double-blind randomized long-term trials (18 participants in each group) after rinsing with PE for 3, 6, and 12 h, and 28 days. Third, we analyzed pro-inflammatory cytokine expression in TR146 cells using quantitative real-time PCR and enzyme-linked immunosorbent assays. Lastly, we assessed pro-inflammatory cytokine secretion and Toll-like receptor (TLR) 2 mRNA expression via the same experimental methods in a three-dimensional oral mucosal epithelial model (3D OMEM)., Results: PE extract dose-dependently inhibited the growth of F. nucleatum (50% inhibition concentration [IC50]=0.079%), P. gingivalis (IC50=0.65%), and S. moorei (IC50=0.07%) and effectively prevented bacterial aggregation. Furthermore, VSC contents decreased significantly at 3, 6, and 12 h after rinsing with 5% PE compared with those in the control. Long-term use of mouthwash containing 5% PE for 28 days led to a significant decrease in VSC contents. PE attenuated the F. nucleatum- or P. gingivalis-stimulated mRNA expression and protein release of interleukin (IL)-6 and IL-8 in TR146 cells. It also suppressed IL-8 and prostaglandin E2 secretion and TLR2 mRNA expression in F. nucleatum-induced OMEMs., Conclusion: Our findings support the use of PE in oral care products to alleviate halitosis and it may reduce inflammation.

Background: Emerging evidence emphasized the role of oral microbiome in oral lichen planus (OLP). To date, no dominant pathogenic bacteria have been identified consistently. It is noteworthy that a decreased abundance of Streptococcus, a member of lactic acid bacteria (LAB) in OLP patients has been commonly reported, indicating its possible effect on OLP. This study aims to investigate the composition of LAB genera in OLP patients by high-throughput sequencing, and to explore the possible relationship between them., Methods: We collected saliva samples from patients with OLP (n = 21) and healthy controls (n = 22) and performed 16 S rRNA gene high-throughput sequencing. In addition, the abundance of LAB genera was comprehensively analyzed and compared between OLP and HC group. To verify the expression of Lactococcus lactis, real time PCR was conducted in buccal mucosa swab from another 14 patients with OLP and 10 HC. Furthermore, the correlation was conducted between clinical severity of OLP and LAB., Results: OLP and HC groups showed similar community richness and diversity. The members of LAB, Lactococcus and Lactococcus lactis significantly decreased in saliva of OLP cases and negatively associated with OLP severity. In addition, Lactococcus and Lactococcus lactis showed negative relationship with Fusobacterium and Aggregatibacter, which were considered as potential pathogens of OLP. Similarly, compared with healthy controls, the amount of Lactococcus lactis in mucosa lesion of OLP patients was significantly decreased., Conclusions: A lower amount of Lactococcus at genus level, Lactococcus lactis at species level was observed in OLP cases and associated with disease severity. Further studies to verify the relationship between LAB and OLP, as well as to explore the precise mechanism is needed., (© 2024. The Author(s).)

Objectives: The aim was to collect different clinical parameters systematically and proactively regarding safety, effectiveness, and performance of a nylon monofilament suture under routine clinical practice for oral surgery., Methods: The study design was prospective, bicentric, international, single-armed, and observational. A non-absorbable suture was applied to close the mucosa after different dental surgical interventions. Main objective was the incidence of combined postoperative complications until suture removal. The 95 % Confidence Interval (Agresti-Coull method) was used to prove the non-inferiority with a pre-specified upper margin of 21.9 %. Secondary variables were intraoperative suture handling, patient pain and satisfaction, wound healing, aesthetic appearance, and bacterial contamination., Results: 105 patients were enrolled. Complication rate was low (1.9 %), 2 swellings occurred. Pain was present for 1.61 days ± 1.42 after various dental interventions with an average pain level of 20.98 ± 22.60 (VAS). Patients with impacted third molar extraction showed the longest pain duration (6 days) combined with the highest mean pain level of 35.33 ± 30.45 (VAS). Intraoperative suture handling was very good to excellent. Suture removal was done after an average duration of 7.56 ± 2.09 days. Patient's satisfaction was high, and an excellent wound healing was reported by the dentists. Aesthetic appearance only performed in implant patients was rated by oral surgeons with an average of 96.19 ± 3.79 points [min. 80 - max. 100] at 5 months postoperatively. Thread bacterial analysis showed that F. nucleatum was the most present species., Conclusions: Our findings indicate that the non-absorbable, nylon-based monofilament suture used is safe and quite suitable for oral mucosal closure after various dental surgical interventions such as tooth extraction, implant placement and impacted third molar extraction., Clinical Significance: This study showed the safe use of a non-absorbable, nylon-based monofilament suture for different oral surgical interventions under daily routine clinical practice., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests. PB is employed by Aesculap AG. IFE is employed by B. Braun Surgical, S.A.U. The other authors declare no conflicts of interest., (Copyright © 2024. Published by Elsevier Ltd.)

Fibroblasts are ubiquitous mesenchymal cells that exhibit considerable molecular and functional heterogeneity. Besides maintaining stromal integrity, oral fibroblast subsets are thought to play an important role in host-microbe interaction during injury repair, which is not well explored in vivo. Here, we characterize a subset of fibroblast lineage labeled by paired-related homeobox-1 promoter activity (Prx1Cre + ) in oral mucosa and skin and demonstrate these fibroblasts readily respond to microbial products to facilitate the normal wound healing process. Using a reporter mouse model, we determined that Prx1Cre + fibroblasts had significantly higher expression of toll-like receptors 2 and 4 compared to other fibroblast populations. In addition, Prx1 immunopositive cells exhibited heightened activation of inflammatory transcription factor NF-κB during the early wound healing process. At the cytokine level, CXCL1 and CCL2 were significantly upregulated by Prx1Cre + fibroblasts at baseline and upon LPS stimulation. Importantly, lineage-specific knockout to prevent NF-κB activation in Prx1Cre + fibroblasts drastically impaired both oral and skin wound healing processes, which was linked to reduced macrophage infiltration, failure to resolve inflammation, and clearance of bacteria. Together, our data implicate a pro-healing role of Prx1-lineage fibroblasts by facilitating early macrophage recruitment and bacterial clearance., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Tobacco use significantly influences the oral microbiome. However, less is known about how different tobacco products specifically impact the oral microbiome over time. To address this knowledge gap, we characterized the oral microbiome of cigarette users, smokeless tobacco users, and non-users over 4 months (four time points). Buccal swab and saliva samples (n = 611) were collected from 85 participants. DNA was extracted from all samples and sequencing was carried out on an Illumina MiSeq, targeting the V3-V4 region of the 16S rRNA gene. Cigarette and smokeless tobacco users had more diverse oral bacterial communities, including a higher relative abundance of Firmicutes and a lower relative abundance of Proteobacteria, when compared to non-users. Non-users had a higher relative abundance of Actinomyces, Granulicatella, Haemophilus, Neisseria, Oribacterium, Prevotella, Pseudomonas, Rothia, and Veillonella in buccal swab samples, compared to tobacco users. While the most abundant bacterial genera were relatively constant over time, some species demonstrated significant shifts in relative abundance between the first and last time points. In addition, some opportunistic pathogens were detected among tobacco users including Neisseria subflava, Bulleidia moorei and Porphyromonas endodontalis. Overall, our results provide a more holistic understanding of the structure of oral bacterial communities in tobacco users compared to non-users., (© 2024. The Author(s).)

Adhesion to mucosal surfaces is a critical step in many bacterial and fungal infections. Here, using a mouse model of oral infection by the human fungal pathobiont Candida albicans, we report the identification of a novel regulator of C. albicans adhesion to the oral mucosa. The regulator is a member of the regulatory factor X (RFX) family of transcription factors, which control cellular processes ranging from genome integrity in model yeasts to tissue differentiation in vertebrates. Mice infected with the C. albicans rfx1 deletion mutant displayed increased fungal burden in tongues compared to animals infected with the reference strain. High-resolution imaging revealed RFX1 transcripts being expressed by C. albicans cells during infection. Concomitant with the increase in fungal burden, the rfx1 mutant elicited an enhanced innate immune response. Transcriptome analyses uncovered HWP1, a gene encoding an adhesion protein that mediates covalent attachment to buccal cells, as a major RFX1-regulated locus. Consistent with this result, we establish that C. albicans adhesion to oral cells is modulated by RFX1 in an HWP1-dependent manner. Our findings expand the repertoire of biological processes controlled by the RFX family and illustrate a mechanism whereby C. albicans can adjust adhesion to the oral epithelium., (© 2024 The Authors. Molecular Microbiology published by John Wiley & Sons Ltd.)

Aim - to improve the methodology for collecting material from lesions of the oral mucosa for exfoliative cytological examination. A group of patients diagnosed with B37.0 Candida stomatitis was examined. To clarify the diagnosis, various methods of collecting biological material from the tongue of patients were used, namely, the method using a cytobrush with subsequent fixation of cytological material on a slide. The microbiota of the back of the tongue was analyzed in 12 patients with glossitis and 12 healthy subjects (the control group). The microscopic method of research was used - using an immersion microscope MICROmed@XS-3330, and the morphological and tinctorial properties of microorganisms were determined. In ten fields of view, the number of leukocytes, the nature of epithelial cells, and the presence of various microorganisms were detected and counted. A comparison of the quality of the use of the microscope method for the study of the tongue microbiota of patients with candidal glossitis was performed under the conditions of taking pathological material using a dental scalpel and an oral cytobrush. For a reasonable interpretation of the results and determination of their significance, a statistical analysis was performed to determine the frequency of detection of microorganisms in patients with glossitis and healthy subjects, depending on the nature of the material taken from the back of the tongue using a dental scalpel or cytobrush. The studies showed that the etiologic structure of glossitis pathogens was dominated by Candida yeast-like fungi, but cases of leptotrichosis aetiology were observed (16.7%). Monococci and gram-negative monobacteria were detected in all studied groups. An increase in the diversity of microorganisms was found when the material was taken with a cytobrush. The microbiota of all subjects differed depending on the type of instrument used for sampling. Thus, in the group of healthy individuals, the interdental brush helped to detect twice as many streptococci as a scalpel. In patients with candidiasis, a brush biopsy showed a 2.7-fold increase in gram-positive diplococci, twice as many streptococci and gram-positive bacilli, three times as many staphylococci, 2.25 times as many clusterforming gram-negative cocci, and 2.3 times as many gram-negative diplococci. A significant increase in the diversity of microorganisms was observed with the cytobrush compared to the use of a dental scalpel. In patients with glossitis, the accumulation of keratinized epithelial cells was significantly higher compared to the presence of young cells in healthy subjects, regardless of the method of sampling.

Background: The study aimed to report all cases of oral tuberculosis (TB), a rare manifestation of the fatal infectious disease primarily affecting the pulmonary system. The report also evaluated the clinicopathological characteristics of oral TB lesions., Methods: A total of 25 patients who presented with oral lesions between August 2013 and August 2023 were diagnosed with TB through surgical biopsy despite having no prior history of the disease. Their clinical symptoms, auxiliary examinations, treatments, and outcomes were recorded and analyzed for further study., Results: In a study of 25 patients with oral TB, all patients were found to have the disease, with 16 males and 9 females affected. The gender distribution was skewed toward males, with a 1.77 male-to-female ratio. Twelve cases of the affected sites were reported in the mandible, six cases in the buccal mucosa, four in the lips, two in the gingiva, and one in the tongue. The age range of affected patients was 0-70 years old, and all lesions were indicative of primary TB. The appearance of the affected mucosa varied, with ulceration and swelling being the most common manifestations., Conclusion: Patients who present with oral ulcerations and swellings should be evaluated for the possibility of TB. To confirm and differentiate this condition from other diseases, obtaining a biopsy specimen for histological analysis and performing acid-fast stains and cultures is recommended. These tests will enable a precise diagnosis and guide appropriate treatment., (Copyright © 2024 Copyright: © 2024 International Journal of Mycobacteriology.)

Background: It is well recognized that both smoke and Candida infection are crucial risk factors for oral mucosal diseases. The nucleotide-binding domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome and its downstream effectors, interleukin (IL)-1β and IL-18, are pivotal to the host defense against Candida and other pathogens., Methods: The present study was designed to explore the effects of cigarette smoke and C. albicans on the NLRP3 inflammasome and its downstream signal pathway via in vitro cell model. Oral epithelial cells (Leuk-1 cells) were exposed to cigarette smoke extract (CSE) for 3 days and/or challenged with C. albicans ., Results: Microscopically, Leuk-1 cells exerted a defense response to C. albicans by markedly limiting the formation of germ tubes and microcolonies. CSE clearly eliminated the defense response of Leuk-1 cells. Functionally, CSE repressed NLRP3 inflammasome, and IL-1β and IL-18 activation induced by C. albicans in Leuk-1 cells., Conclusion: Our results suggested that in oral epithelial cells, the NLRP3 inflammasome might be one of the target pathways by which CSE attenuates innate immunity and leads to oral disorders., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Objective: To characterize the bacterial community from different oral niches (buccal mucosa and saliva) in oral lichen planus (OLP) patients., Subjects and Methods: This preliminary study analyzed site-specific (mucosa and saliva) microbial landscape of 20 OLP patients and 10 healthy controls., Results: The microbial diversity was similar between OLP patients and healthy controls in both salivary and mucosal communities. However, the topological properties of co-occurrence networks of salivary and mucosal microbiome were different between healthy controls and OLP patients. SparCC analysis inferred three and five keystone taxa in the salivary and mucosal microbial networks of healthy controls, respectively. However, in the salivary and mucosal bacterial networks of OLP patients, only one hub OTU and three OTUs were identified as keystone taxa, respectively. In addition, analysis of community cohesion revealed that mucosal microbial community in OLP patients had lower stability than that in healthy controls. In final, correlation assay showed that the clinical severity of OLP was positively associated with the relative abundance of Rothia in saliva but negatively associated with that of Porphyromonas on mucosa., Conclusions: The salivary and mucosal bacterial communities of OLP patients differ in terms of composition, the genera associated with OLP severity, and co-occurrence patterns., (© 2023 Wiley Periodicals LLC.)

Oral mucositis (OM) is a complex acute cytotoxicity of antineoplastic treatment that affects 40-85% of patients undergoing hematopoietic stem-cell transplantation. OM is associated with prolonged hospitalization, increased extensive pharmacotherapy, need for parenteral nutrition, and elevated treatment costs. As OM onset relates to the mucosal microenvironment status, with a particular role for microbiota-driven inflammation, we aimed to investigate whether the oral mucosa microbiota was associated with the clinical course of OM in patients undergoing allogeneic hematopoietic stem-cell transplantation. We collected oral mucosa samples from 30 patients and analyzed the oral mucosa microbiota by 16S rRNA sequencing. A total of 13 patients (43%) developed ulcerative OM. We observed that specific taxa were associated with oral mucositis grade and time to oral mucositis healing. Porphyromonas relative abundance at preconditioning was positively correlated with ulcerative OM grade (Spearman ρ = 0.61, P = 0.028) and higher Lactobacillus relative abundance at ulcerative OM onset was associated with shortened ulcerative OM duration (P = 0.032). Additionally, we generated a machine-learning-based bacterial signature that uses pre-treatment microbial profiles to predict whether a patient will develop OM during treatment. Our findings suggest that further research should focus on host-microbiome interactions to better prevent and treat OM., (© 2022. The Author(s).)

Candida albicans (C. albicans) is a dimorphic commensal human fungal pathogen that can cause severe oropharyngeal candidiasis (oral thrush) in susceptible hosts. During invasive infection, C. albicans hyphae invade oral epithelial cells (OECs) and secrete candidalysin, a pore-forming cytolytic peptide that is required for C. albicans pathogenesis at mucosal surfaces. Candidalysin is produced in the hyphal invasion pocket and triggers cell damage responses in OECs. Candidalysin also activates multiple MAPK-based signaling events that collectively drive the production of downstream inflammatory mediators that coordinate downstream innate and adaptive immune responses. The activities of candidalysin are dependent on signaling through the epidermal growth factor receptor (EGFR). Here, we interrogated known EGFR-MAPK signaling intermediates for their roles mediating the OEC response to C. albicans infection. Using RNA silencing and pharmacological inhibition, we identified five key adaptors, including growth factor receptor-bound protein 2 (Grb2), Grb2-associated binding protein 1 (Gab1), Src homology and collagen (Shc), SH2-containing protein tyrosine phosphatase-2 (Shp2), and casitas B-lineage lymphoma (c-Cbl). We determined that all of these signaling effectors were inducibly phosphorylated in response to C. albicans. These phosphorylation events occurred in a candidalysin-dependent manner and additionally required EGFR phosphorylation, matrix metalloproteinases (MMPs), and cellular calcium flux to activate a complete OEC response to fungal infection. Of these, Gab1, Grb2, and Shp2 were the dominant drivers of ERK1/2 activation and the subsequent production of downstream innate-acting cytokines. Together, these results identify the key adaptor proteins that drive the EGFR signaling mechanisms that underlie oral epithelial responses to C. albicans., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Pseudomembranous candidiasis (thrush), erythematous candidiasis, and fungal esophagitis are infections of the barrier mucosa of the upper gastrointestinal tract. The majority of these infections are caused by Candida albicans , an opportunistic fungal pathogen that frequently exists as a harmless commensal on mucosal surfaces lining the gastrointestinal tract. Oral infections are initiated in the superficial stratified squamous epithelium, in which keratinocytes are the most abundant host cells and are the initial points of contact with C. albicans present in saliva. Intrinsic features of oral keratinocytes are likely to play important roles in host defense and tissue homeostasis in oral candidiasis. One understudied pathway that may be important for modulating oral candidiasis is the IL-20 cytokine signaling pathway that employs keratinocyte IL-20RB receptors as ligands for IL-19, IL-20, and IL-24. We report that production of human oral keratinocyte il24 mRNA and protein are stimulated during co-culture with C. albicans . To test the role of the IL-20 family signaling pathway in oral candidiasis, Il20rb -/- mice (lacking the IL-20RB receptor) were compared to wild-type mice in a murine model of oropharyngeal candidiasis. Fungal burdens and percent loss in body weight were determined. Despite comparable fungal burdens, the Il20rb -/- mice exhibited less weight loss over the course of their infection compared to the B6 mice, suggestive of reduced overall disease consequences in the mutant mice. Interference with IL-20 family cytokine signaling may be useful for augmenting the ability of the host to defend itself against pathogens., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Beute, Kim, Park, Yang, Torres-Shafer, Mullins and Sundstrom.)

A side effect of antibiotics is outgrowth of the opportunistic fungus Candida albicans in the oropharynx (oropharyngeal candidiasis, OPC). IL-17 signaling is vital for immunity to OPC, but how the microbiome impacts antifungal immunity is not well understood. Mice in standard specific pathogen-free (SPF) conditions are resistant to OPC, whereas we show that germ-free (GF) or antibiotic-treated mice are susceptible. Oral type 17 cells and IL-17-dependent responses were impaired in antibiotic-treated and GF mice. Susceptibility could be rescued in GF mice by mono-colonization with segmented filamentous bacterium (SFB), an intestine-specific constituent of the microbiota. SFB protection was accompanied by restoration of oral IL-17+CD4+ T cells and gene signatures characteristic of IL-17 signaling. Additionally, RNA-Seq revealed induction of genes in the retinoic acid (RA) and RA receptor-α (RARα) pathway. Administration of RA rescued immunity to OPC in microbiome-depleted or GF mice, while RAR inhibition caused susceptibility in immunocompetent animals. Surprisingly, immunity to OPC was independent of serum amyloids. Moreover, RAR inhibition did not alter oral type 17 cytokine levels. Thus, mono-colonization with a component of the intestinal microflora confers protection against OPC by type 17 and RA/RARα, which act in parallel to promote antifungal immunity. In principle, manipulation of the microbiome could be harnessed to maintain antifungal immunity.

As part of the human microbiota, the fungus Candida albicans colonizes the oral cavity and other mucosal surfaces of the human body. Commensalism is tightly controlled by complex interactions of the fungus and the host to preclude fungal elimination but also fungal overgrowth and invasion, which can result in disease. As such, defects in antifungal T cell immunity render individuals susceptible to oral thrush due to interrupted immunosurveillance of the oral mucosa. The factors that promote commensalism and ensure persistence of C. albicans in a fully immunocompetent host remain less clear. Using an experimental model of C. albicans oral colonization in mice we explored fungal determinants of commensalism in the oral cavity. Transcript profiling of the oral isolate 101 in the murine tongue tissue revealed a characteristic metabolic profile tailored to the nutrient poor conditions in the stratum corneum of the epithelium where the fungus resides. Metabolic adaptation of isolate 101 was also reflected in enhanced nutrient acquisition when grown on oral mucosa substrates. Persistent colonization of the oral mucosa by C. albicans also correlated inversely with the capacity of the fungus to induce epithelial cell damage and to elicit an inflammatory response. Here we show that these immune evasive properties of isolate 101 are explained by a strong attenuation of a number of virulence genes, including those linked to filamentation. De-repression of the hyphal program by deletion or conditional repression of NRG1 abolished the commensal behaviour of isolate 101, thereby establishing a central role of this factor in the commensal lifestyle of C. albicans in the oral niche of the host., Competing Interests: We have read the journal’s policy and the authors of this manuscript have the following competing interests:Simon Altmeier is now an employee of Novartis. His findings presented in this paper are solely his views and are independent from Novartis work. The other authors have no competing interest to declare.

Evidence suggests that Helicobacter pylori plays a role in gastric cancer (GC) initiation. However, epidemiologic studies on the specific role of other bacteria in the development of GC are lacking. We conducted a case-control study of 89 cases with gastric intestinal metaplasia (IM) and 89 matched controls who underwent upper gastrointestinal endoscopy at three sites affiliated with NYU Langone Health. We performed shotgun metagenomic sequencing using oral wash samples from 89 case-control pairs and antral mucosal brushing samples from 55 case-control pairs. We examined the associations of relative abundances of bacterial taxa and functional pathways with IM using conditional logistic regression with and without elastic-net penalty. Compared with controls, oral species Peptostreptococcus stomatis, Johnsonella ignava, Neisseria elongata and Neisseria flavescens were enriched in cases (odds ratios [ORs] = 1.29-1.50, P = .004-.01) while Lactobacillus gasseri, Streptococcus mutans, S parasanguinis and S sanguinis were under-represented (ORs = 0.66-0.76, P = .006-.042) in cases. Species J ignava and Filifactor alocis in the gastric microbiota were enriched (ORs = 3.27 and 1.43, P = .005 and .035, respectively), while S mutans, S parasanguinis and S sanguinis were under-represented (ORs = 0.61-0.75, P = .024-.046), in cases compared with controls. The lipopolysaccharide and ubiquinol biosynthesis pathways were more abundant in IM, while the sugar degradation pathways were under-represented in IM. The findings suggest potential roles of certain oral and gastric microbiota, which are correlated with regulation of pathways associated with inflammation, in the development of gastric precancerous lesions., (© 2021 UICC.)

Introduction: Smoked, and especially smokeless, tobacco are major causes of oral cancer globally. Here, we examine the oral bacteriome of smokers and of smokeless tobacco users, in comparison to healthy controls, using 16S rRNA gene sequencing., Methods: Oral swab samples were collected from smokers, smokeless tobacco users, and healthy controls (n = 44). Microbial DNA was extracted and the 16S rRNA gene profiled using the Illumina MiSeq platform. Sequencing reads were processed using DADA2, and taxonomical classification was performed using the phylogenetic placement method. Differentially abundant taxa were identified using DESeq2, while functional metagenomes based on KEGG orthology abundance were inferred using LIMMA., Results: A significantly higher microbial diversity was observed in smokeless tobacco users and smokers relative to controls (P < 0.05). Compositional differences in microbial communities were observed in all comparisons with healthy controls (PERMANOVA P < 0.05) but not between smokers and smokeless tobacco users. Levels of Fusobacterium spp., Saccharibacterium spp., and members of Shuttleworthia were elevated in smokers when compared to controls (BH adj P < 0.01). In addition, the relative abundance of three bacterial taxa belonging to genera Fusobacterium spp., Catonella, and Fretibacterium spp. was significantly increased in smokeless tobacco users relative to controls (BH adj P < 0.01). Major functional pathways significantly increased in smokeless tobacco users relative to both controls, and smokers were similar and involved amino acid metabolism including glutamate and aspartate biosynthesis and degradation (log FC > 1.5; BH adj P < 0.01)., Conclusions: A distinct taxonomic and functional profile of oral microbiome in smokers and smokeless tobacco users as compared to healthy controls implicates a significant role of microbes and their metabolites in diseases associated with tobacco use including oral cancer., Clinical Relevance: Future efforts in preventive, diagnostic, curative, and prognostic strategies for diseases associated with tobacco use in smokers and smokeless tobacco users could incorporate the oral microbiome., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The oral cavity is inhabited by a wide spectrum of microbial species, and their colonization is mostly based on commensalism. These microbes are part of the normal oral flora, but there are also opportunistic species that can cause oral and systemic diseases. Although there is a strong exposure to various microorganisms, the oral mucosa reduces the colonization of microorganisms with high rotation and secretion of various types of cytokines and antimicrobial proteins such as defensins. In some circumstances, the imbalance between normal oral flora and pathogenic flora may lead to a change in the ratio of commensalism to parasitism. Healthy oral mucosa has many important functions. Thanks to its integrity, it is impermeable to most microorganisms and constitutes a mechanical barrier against their penetration into tissues. Our study aims to present the role and composition of the oral cavity microbiota as well as defense mechanisms within the oral mucosa which allow for maintaining a balance between such numerous species of microorganisms. We highlight the specific aspects of the oral mucosa protecting barrier and discuss up-to-date information on the immune cell system that ensures microbiota balance. This study presents the latest data on specific tissue stimuli in the regulation of the immune system with particular emphasis on the resistance of the gingival barrier. Despite advances in understanding the mechanisms regulating the balance on the microorganism/host axis, more research is still needed on how the combination of these diverse signals is involved in the regulation of immunity at the oral mucosa barrier.

In periodontal health, oral streptococci constitute up to 80% of the plaque biofilm. Yet, destructive inflammatory events of the periodontium are rare. This observation suggests that oral streptococci may possess mechanisms to co-exist with the host. However, the mechanisms employed by oral streptococci to modulate the innate immune response have not been well studied. One of the key virulence factors produced by oral streptococci is hydrogen peroxide (H 2 O 2 ). In mammalian cells, H 2 O 2 triggers the activation of nuclear factor erythroid 2-related factor 2 (Nrf2), a key pathway mediating antioxidant defence. This study aimed to determine (1) if H 2 O 2 producing oral streptococci activated the Nrf2 pathway in macrophages, and (2) if the activation of Nrf2 influenced the innate immune response. We found that oral streptococci downregulated the innate immune response in a H 2 O 2 dependent manner through the activation of the Nrf2. The activation of the Nrf2 signalling pathway led to the inhibition of nuclear factor kappa-light-chain-enhancer of activated B cells (NFĸB), the key transcription factor regulating pro-inflammatory response. This study showed for the first time that oral streptococci are unlikely passive bystanders but could play an active role in the maintenance of periodontal health by preventing overt inflammation., (© 2022. The Author(s).)

Objective: The aim: To study the relationship between the degree severity of changes in the tunica mucosa of the rats gums and the composition of the microbiota of tooth surface in the gingival margin under the ten-week action of the opioid., Patients and Methods: Materials and methods: The study was performed on 34 male rats, weighing 160 - 255 g, aged 4.5 - 7 months. Animals were administered nalbuphine for 10 weeks, gradually increasing the dose (0.212 - 0.283 mg/kg). The research of the bacterial from the microbiotope of tooth surface in the gingival margin of rats was performed using statistical analysis of quantitative results., Results: Results: The 4 stages of development of the pathological process and changes in the qualitative and quantitative composition of the microbiocenosis in the gingival margin of the oral mucosa are determined. Depending on the severity of pathological changes in the mucous membrane of the gums of rats under the long-term action of the opioid, a significant increase in the quantitative indicators of bacterial species of pathogenic and opportunistic microbiota at degree IV of the process compared with degree I. The appearance of potential pathogens of purulent-inflammatory processes - Klebsiella and Pseudomonas aeruginosa was noted., Conclusion: Conclusions: The relationship between the quantitative and qualitative characteristics of the microbiocenosis of tooth surface in the gingival margin and the severity of changes in the mucous membrane of the of rats gums under the ten-week action of the opioid was determined, indicating bacterial associations of dental biopellicle as an etiological factor.

The Aim of the Study: The study by the method of tissue polymerase chain reaction of the species composition of the microbiota of lesions of the oral mucosa in patients with bullous lesions., Material and Methods: Biopsy specimens of the oral mucosa of 51 patients were studied by the polymerase chain reaction method, of which 14 patients with pemphigus vulgaris, 17 patients with pemphigoid bullosa, and 20 patients with the bullous form of ruber lichen planus. 4 types of microorganisms have been identified - Fusobacterium, Streptococcus pneumoniae, Candida albicans, Ureaplasma spp. and viruses - Human Papillomavirus 16, Epstein-Barr virus and Citomegalovirus., Results: In the study of the microbiota of bullous lesions, associations of microorganisms and viruses were established in a significant number of cases. Associations of Str.pneumoniae and C. albicans were quite common in patients with pemphigus vulgaris in 26.3%, pemphigoid bullosa in 20.0%, and in patients with the bullous form of ruber lichen planus in 14.3% of cases. In patients with pemphigus vulgaris, the association of Str.pneumoniae, C. albicans and EBV was noted in 31.6% of cases. In patients with the bullous form of ruber lichen planus in a high percentage of cases (28.6%), the associations of Str. pneumoniae, EBV and CMV., Conclusion: Identification at earlier stages of management of patients with bullous lesions Str. pneumoniae, Candida albicans, and Fusobacterium associated with herpes viruses should be regarded as one of the triggering mechanisms of an autoimmune conflict, which subsequently causes a specific clinical picture of these diseases.

Aphthous stomatitis (AS) is one of the most common diseases of the oral mucosa in children. A significant role in the pathogenesis of AS is assigned to the infectious-allergic factor., The Aim: Of the work was to evaluate the clinical effectiveness of topical application of bacteriophages in the complex treatment of children with aphthous stomatitis., Materials and Methods: The main group included 30 children with AS aged 4 to 15 years. The control group consisted of 20 healthy children without AS and without concomitant somatic pathology at the age of 4 to 15 years. The effectiveness of the therapy was evaluated based on the results of repeated bacteriological examination of the oral microflora, conducted 1 month after phage treatment, as well as the dynamics of clinical manifestations: reduction in size or complete epithelization of defects., Results: The use of bacteriophage in the complex treatment of children with AS was accompanied by positive dynamics of clinical and laboratory parameters in all patients: a significant decrease in microbial contamination and the number of individual pathogenic microflora species against the background of normalization of local microbiocenosis in the oral cavity., Conclusion: The obtained clinical and laboratory data allowed improving the scheme of complex treatment of AS in children by the use of bacteriophages.

Tissue-specific cues are critical for homeostasis at mucosal barriers. Here, we report that the clotting factor fibrin is a critical regulator of neutrophil function at the oral mucosal barrier. We demonstrate that commensal microbiota trigger extravascular fibrin deposition in the oral mucosa. Fibrin engages neutrophils through the α M β 2 integrin receptor and activates effector functions, including the production of reactive oxygen species and neutrophil extracellular trap formation. These immune-protective neutrophil functions become tissue damaging in the context of impaired plasmin-mediated fibrinolysis in mice and humans. Concordantly, genetic polymorphisms in PLG , encoding plasminogen, are associated with common forms of periodontal disease. Thus, fibrin is a critical regulator of neutrophil effector function, and fibrin-neutrophil engagement may be a pathogenic instigator for a prevalent mucosal disease.

Objective: Face masks help contain the aerosol-mediated transmission of infectious viral particles released from individuals via cough and sneezes. However, the prolonged use of face masks has raised concerns regarding oral hygiene. Here, we present a mouthwash formulation based on α-cyclodextrin and hydroxytyrosol that can maintain healthy oral microbiota., Materials and Methods: We isolated and cultured Candida albicans, Staphylococcus aureus, and a mix of Streptococcus sp., Staphylococcus sp. and Neisseria sp. from oral and throat swabs. The microorganisms were cultured in a standard medium with or without the mouthwash. To evaluate the effect of the mouthwash on the oral microbiota, the DNA from the saliva of 3 volunteers that used the mouthwash was extracted. Then, the DNA was amplified using primer pairs specific for bacterial and fungal DNA. Twelve further volunteers were offered to use the mouthwash and a questionnaire was submitted to them to assess the possible beneficial effects of mouthwash on halitosis and other oral disturbances., Results: The bacteria and fungi cultured in media containing the mouthwash showed a growth reduction ranging from 20 to 80%. The PCR amplification of fungal and bacterial DNA extracted from volunteers that used the mouthwash showed a reduction of both bacteria and fungi. Volunteers that used the mouthwash reported a tendency towards a reduction of halitosis, gingival and mouth inflammation, and dry mouth., Conclusions: The use of a mouthwash containing α-cyclodextrin and hydroxytyrosol is not aggressive against oral mucosa; it is safe and effective to reduce the bacterial and fungal load due to the continuous use of face masks.

The early-life microbiome (ELM) interacts with the psychosocial environment, in particular during early-life adversity (ELA), defining life-long health trajectories. The ELM also plays a significant role in the maturation of the immune system. We hypothesised that, in this context, the resilience of the oral microbiomes, despite being composed of diverse and distinct communities, allows them to retain an imprint of the early environment. Using 16S amplicon sequencing on the EpiPath cohort, we demonstrate that ELA leaves an imprint on both the salivary and buccal oral microbiome 24 years after exposure to adversity. Furthermore, the changes in both communities were associated with increased activation, maturation, and senescence of both innate and adaptive immune cells, although the interaction was partly dependent on prior herpesviridae exposure and current smoking. Our data suggest the presence of multiple links between ELA, Immunosenescence, and cytotoxicity that occur through long-term changes in the microbiome.

Oral mucosal disease (OMD), which is also called soft tissue oral disease, is described as a series of disorders or conditions affecting the mucosa and soft tissue in the oral cavity. Its etiology is unclear, but emerging evidence has implicated the influence of the composition of the oral mucosa and saliva-resident microbiota. In turn, this dysbiosis effects the immune response balance and epithelial barrier function, followed by the occurrence and progression of OMD. In addition, oral microbial dysbiosis is diverse in different types of diseases and different disease progressions, suggesting that key causal pathogens may exist in various oral pathologies. This narrative literature review primarily discusses the most recent findings focusing on how microbial dysbiosis communicates with mucosal adaptive immune cells and the epithelial barrier in the context of five representative OMDs, including oral candidiasis (OC), oral lichen planus (OLP), recurrent aphthous ulcer (RAU), oral leukoplakia (OLK), and oral squamous cell carcinoma (OSCC), to provide new insight into the pathogenetic mechanisms of OMDs., (© 2021. The Author(s), under exclusive licence to Society for Mucosal Immunology.)

Radiotherapy is inevitably intertwined with various side effects impairing the quality of life of cancer patients. Here, we report the possibility that alterations of the oral microbiota influence the therapeutic efficacy and prognosis of radiotherapy for primary rectal cancer and colorectal cancer (CRC) liver metastases that pathologically disrupt gastrointestinal integrity and function. 16S rRNA sequencing shows that oral microbiota alterations change the gut bacterial composition within tumors but not in adjacent peritumor tissues in CRC mouse models. Specifically, buccal Fusobacterium nucleatum migrates to the CRC locus and impairs the therapeutic efficacy and prognosis of radiotherapy. Administration of a specific antibiotic, metronidazole, abrogates the adverse effects of oral microbiome fluctuation on radiotherapy for CRC. The oral microbiota were also associated with radiation-induced intestinal injury via intestinal microbes. Our findings demonstrate that the oral microbiome in synergy with its intestinal counterparts impinges on the efficacy and prognosis of radiotherapy for CRC., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objective: Periodontitis is an inflammatory disease of microbial etiology caused primarily by dysbiosis of the oral microbiota. Our aim was to compare variations in the composition of the oral microbiomes of youths with severe periodontitis according to gender., Methods: Subgingival plaque samples collected from 17 patients with severe periodontitis (11 males and 6 females) were split for 16S rRNA gene sequencing. The composition, α -diversity, and β -diversity of the patients' oral microbiomes were compared between the males and the females. Linear discriminant analysis effect size (LEfSe) was used to analyze the specific taxa enriched in the two groups. Functional profiles (KEGG pathways) were obtained using PICRUSt based on 16S rRNA gene sequencing data., Results: The Chao1 index and phylogenetic diversity whole tree were significantly higher in males than in females. The Simpson and Shannon indices were not significantly different between the two groups. β -Diversity suggested that the samples were reasonably divided into groups. The Kruskal-Wallis test based on the relative abundance of species, combined with the LEfSe analysis showed that the dominant bacteria in males were Pseudomonas and Papillibacter , whereas the dominant bacteria in women were Fusobacteriales and Tannerella . KEGG analysis predicted that the variation in the oral microbiome may be related to the immune system in women, whereas immune system diseases were the dominant pathway in men., Conclusion: We found sex-specific differences in the oral microbiome in a sample of youths with severe periodontitis. The differences may be related to changes in immune homeostasis and lead to a better understanding of periodontitis., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this paper., (Copyright © 2021 Ya-Qiong Zhao et al.)

The association of taste genetics and the oral microbiome in autoimmune diseases such as rheumatoid arthritis (RA) has not been reported. We explored a novel oral mucosal innate immune pathway involving the bitter taste G protein-coupled receptor T2R38. This case-control study aimed to evaluate whether T2R38 polymorphisms associate with the buccal microbial composition in RA. Genomic DNA was obtained from buccal swabs of 35 RA patients and 64 non-RA controls. TAS2R38 genotypes were determined by Sanger sequencing. The buccal microbiome was assessed by Illumina MiSeq sequencing of the V4- 16S rRNA gene. Bacterial community differences were analyzed with alpha and beta diversity measures. Linear discriminant analysis effect size identified taxa discriminating between RA versus non-RA and across TAS2R38 genotypes. TAS2R38 genotype frequency was similar between RA and non-RA controls (PAV/PAV; PAV/AVI; AVI/AVI: RA 42.9%; 45.7%; 11.4% versus controls 32.8%; 48.4%; 18.8%, chi-square (2, N = 99) = 2.1, p = 0.35). The relative abundance of Porphyromonas, among others, differed between RA and non-RA controls. The relative abundance of several bacterial species also differed across TAS2R38 genotypes. These findings suggest an association between T2R38 polymorphisms and RA buccal microbial composition. However, further research is needed to understand the impact of T2R38 in oral health and RA development.

The microbial composition of a specific oral niche could be influenced by initial bacterial adherence, nutrient and physiological property of the local surface. To investigate the influence of nutrient and surface properties on microbial composition, saliva-derived biofilms were grown in agar on three substrata: Reconstructed Human Gingiva (RHG), a hydroxyapatite (HAP) surface, and a titanium (TI) surface. Agar was mixed with either Brain Heart Infusion (BHI) or Thompson (TP) medium. After 1, 3, or 5 days, biofilm viability (by colony forming units) and microbiome profiles (by 16 S rDNA amplicon sequencing) were determined. On RHG, biofilm viability and composition were similar between BHI and TP. However, on the abiotic substrata, biofilm properties greatly depended on the type of medium and substratum. In BHI, the viability of HAP-biofilm first decreased and then increased, whereas that of TI-biofilm decreased in time until a 6-log reduction. In TP, either no or a 2-log reduction in viability was observed for HAP- or TI-biofilms respectively. Furthermore, different bacterial genera (or higher level) were differentially abundant in the biofilms on 3 substrata: Haemophilus and Porphyromonas for RHG; Bacilli for HAP and Prevotella for TI. In conclusion, RHG, the biotic substratum, is able to support a highly viable and diverse microbiome. In contrast, the viability and diversity of the biofilms on the abiotic substrata were influenced by the substrata type, pH of the environment and the richness of the growth media. These results suggest that the host (oral mucosa) plays a vital role in the oral ecology., (© 2021. The Author(s).)

Intestinal microbiota (IM) diversity and composition regulates host immunity and affects outcomes after allogeneic stem cell transplantation (allo-HSCT). We evaluated if the oral mucosa microbiota (OM) could impact the outcomes in patients who underwent allo-HSCT. Samples from the oral mucosa of 30 patients were collected at three time points: before the conditioning regimen, at aplasia, and at engraftment. We analyzed the associations of OM diversity and composition with allo-HSCT outcomes. Lower OM diversity at preconditioning was associated with a higher risk of relapse at 3 years (68% versus 33%, respectively; P = 0.04). Dominance (relative abundance ≥ 30%) by a single genus at preconditioning was also associated with a higher risk of relapse (63% versus 36% at 3 years, respectively; P = 0.04), as well as worse progression-free survival (PFS; 19% versus 55%, respectively; P = 0.01), and overall survival (OS) at 3 years (38% versus 81%, respectively; P = 0.02). In our study we observed that OM dysbiosis is associated with a higher risk of relapse and worse survival after allo-HSCT., (© 2021. The Author(s).)