Streptococcus Salivarius: A Potential Salivary Biomarker for Orofacial Granulomatosis and Crohn's Disease?

Identification of Putative Bacterial Pathogens for Orofacial Granulomatosis Based on 16S rRNA Metagenomic Analysis

Orofacial granulomatosis (OFG) is a chronic inflammatory disease characterized by nontender swelling of the orofacial tissues, the underlying cause of which remains unknown. Our previous study demonstrated that tooth apical periodontitis (AP) is involved in the development of OFG. To characterize the AP bacterial signatures of OFG patients and identify possible pathogenic bacteria that cause OFG, the compositions of the AP microbiotas in OFG patients and controls were compared using 16S rRNA gene sequencing. Pure cultures of putative bacterial pathogens were established by growing bacteria as colonies followed by purification, identification, and enrichment and then were injected into animal models to determine the causative bacteria contributing to OFG. A specific AP microbiota signature in the OFG patients was shown, characterized by the predominance of phyla Firmicutes and Proteobacteria, notably members of the genera Streptococcus, Lactobacillus, and Neisseria, were found. Streptococcus spp., Lactobacillus casei, Neisseria subflava, Veillonella parvula, and Actinomyces spp. from OFG patients were isolated and successfully cultured in vitro and then injected into mice. Ultimately, footpad injection with N. subflava elicited granulomatous inflammation. IMPORTANCE Infectious agents have long been considered to play a role in the initiation of OFG; however, a direct causal relationship between microbes and OFG has not yet been established. In this study, a unique AP microbiota signature was identified in OFG patients. Moreover, we successfully isolated candidate bacteria from AP lesions of OFG patients and assessed their pathogenicity in laboratory mice. Findings from this study may help provide in-depth insights into the role of microbes in OFG development, providing the basis for targeted therapeutic approaches for OFG.

Gingival Orofacial Granulomatosis Clinical and 2D/3D Microscopy Features after Orthodontic Therapy: A Pediatric Case Report

Orofacial granulomatosis (OFG) represents a heterogeneous group of rare orofacial diseases. When affecting gingiva, it appears as a chronic soft tissue inflammation, sometimes combined with the enlargement and swelling of other intraoral sites, including the lips. Gingival biopsy highlights noncaseating granulomatous inflammation, similar to that observed in Crohn’s disease and sarcoidosis. At present, the etiology of OFG remains uncertain, although the involvement of the genetic background and environmental triggers, such as oral conditions or therapies (including orthodontic treatment), has been suggested. The present study reports the results of a detailed clinical and 2D/3D microscopy investigation of a case of gingival orofacial granulomatosis in an 8-year-old male patient after orthodontic therapy. Intraoral examination showed an erythematous hyperplasia of the whole gingiva with a granular appearance occurring a few weeks after the installation of a quad-helix. Peri-oral inspection revealed upper labial swelling and angular cheilitis. General investigations did not report ongoing extra-oral disturbances with the exception of a weakly positive anti-Saccharomyces cerevicae IgG auto-antibody. Two- and three-dimensional microscopic investigations confirmed the presence of gingival orofacial granulomatosis. Daily corticoid mouthwashes over a period of 3 months resulted in a slight improvement in clinical signs, despite an intermittent inflammation recurrence. This study brings new insights into the microscopic features of gingival orofacial granulomatosis, thus providing key elements to oral practitioners to ensure accurate and timely OFG diagnosis. The accurate diagnosis of OFG allows targeted management of symptoms and patient monitoring over time, along with early detection and treatment of extra-oral manifestations, such as Crohn’s disease.

Mucin glycans drive oral microbial community composition and function

Human microbiome composition is closely tied to health, but how the host manages its microbial inhabitants remains unclear. One important, but understudied, factor is the natural host environment: mucus, which contains gel-forming glycoproteins (mucins) that display hundreds of glycan structures with potential regulatory function. Leveraging a tractable culture-based system to study how mucins influence oral microbial communities, we found that mucin glycans enable the coexistence of diverse microbes, while resisting disease-associated compositional shifts. Mucins from tissues with unique glycosylation differentially tuned microbial composition, as did isolated mucin glycan libraries, uncovering the importance of specific glycan patterns in microbiome modulation. We found that mucins shape microbial communities in several ways: serving as nutrients to support metabolic diversity, organizing spatial structure through reduced aggregation, and possibly limiting antagonism between competing taxa. Overall, this work identifies mucin glycans as a natural host mechanism and potential therapeutic intervention to maintain healthy microbial communities.

Management of orofacial granulomatosis

Orofacial granulomatosis is a chronic relapsing-remitting inflammatory condition that shares a similar phenotypic presentation to some other granulomatous diseases, particularly Crohn's disease. However, subtle clinical and pathological differences justify it as a separate disease entity. Previous studies have assessed the effectiveness of interventions used in the management of orofacial granulomatosis. This article reviews the management options available. A literature search was conducted to identify studies, in English, which assessed the effect of non-pharmacological and pharmacological interventions in the treatment of orofacial granulomatosis. The interventions were categorised into dietary modification, pharmacological (topical, intralesional and systemic therapy), surgery and psychological. A combination of interventions is often required to effectively manage each patient. There is convincing evidence that diet plays a role in disease severity. In patients where dietary manipulation alone is unsuccessful, topical, intralesional and/or systemic treatment may be considered to manage the condition.

Nanomaterials for optical biosensors in forensic analysis

Biosensors are compact analytical devices capable of transducing a biological interaction event into a measurable signal outcome in real-time. They can provide sensitive and affordable analysis of samples without the need for additional laboratory equipment or complex preparation steps. Biosensors may be beneficial for forensic analysis as they can facilitate large-scale high-throughput, sensitive screening of forensic samples to detect target molecules that are of high evidential value. Nanomaterials are gaining attention as desirable components of biosensors that can enhance detection and signal efficiency. Biosensors that incorporate nanomaterials within their design have been widely reported and developed for medical purposes but are yet to find routine employment within forensic science despite their proven potential. In this article, key examples of the use of nanomaterials within optical biosensors designed for forensic analysis are outlined. Their design and mechanism of detection are both considered throughout, discussing how nanomaterials can enhance the detection of the target analyte. The critical evaluation of the optical biosensors detailed within this review article should help to guide future optical biosensor design via the incorporation of nanomaterials, for not only forensic analysis but alternative analytical fields where such biosensors may prove a valuable addition to current workflows.

The role of gut microbiome in inflammatory bowel disease diagnosis and prognosis

Inflammatory bowel disease (IBD) is a chronic immune-mediated intestinal disease consisting of ulcerative colitis and Crohn's disease. Inflammatory bowel disease is believed to be developed as a result of interactions between environmental, immune-mediated and microbial factors in a genetically susceptible host. Recent advances in high-throughput sequencing technologies have aided the identification of consistent alterations of the gut microbiome in patients with IBD. Preclinical and murine models have also shed light on the role of beneficial and pathogenic bacteria in IBD. These findings have stimulated interest in development of non-invasive microbial and metabolite biomarkers for predicting disease risk, disease progression, recurrence after surgery and responses to therapeutics. This review briefly summarizes the current evidence on the role of gut microbiome in IBD pathogenesis and mainly discusses the latest literature on the utilization of potential microbial biomarkers in disease diagnosis and prognosis.

The oral microbiome in treatment naïve paediatric IBD patients exhibits dysbiosis related to disease severity that resolves following therapy

BACKGROUND

There is a limited literature describing the oral microbiome and its diagnostic potential in paediatric inflammatory bowel disease (IBD).

METHODS

We examined the dorsum tongue microbiome by V1-V2 sequencing in a cohort of 156 treatment naïve children diagnosed with IBD compared to 102 healthy control children. Microbiome changes over time following treatment were examined in a subset of patients and associations between IBD diagnosis and dysbiosis were explored.

RESULTS

Analysis of community structure of the microbiome in tongue samples revealed that IBD samples significantly diverged from healthy control samples (PERMANOVA P=0.0009) and exhibited a reduced abundance of Clostridia in addition to several major oral genera (Veillonella, Prevotella, Fusobacterium species) with an increased abundance of streptococci. This dysbiosis was more marked in patients with severe disease. Higher levels of the potential pathobionts Klebsiella and Pseudomonas spp. were also associated with IBD. In terms of predicted functions, the IBD oral microbiome was potentially more acidogenic and exhibited reduced capacity for B vitamin biosynthesis. We used a machine learning approach to develop a predictive model of IBD which exhibited a mean-prediction AUC: 0.762. Finally, we examined a subset of 53 patients following 12 months of therapy and could show resolution of oral dysbiosis demonstrated by a shift towards a healthy community structure and a significant reduction in oral dysbiosis.

CONCLUSION

Oral dysbiosis found in children with IBD is disease severity related and resolves over time following successful IBD treatment.

Offense and Defense in Granulomatous Inflammation Disease

Granulomatous inflammation (GI) diseases are a group of chronic inflammation disorders characterized by focal collections of multinucleated giant cells, epithelioid cells and macrophages, with or without necrosis. GI diseases are closely related to microbes, especially virulent intracellular bacterial infections are important factors in the progression of these diseases. They employ a range of strategies to survive the stresses imposed upon them and persist in host cells, becoming the initiator of the fighting. Microbe-host communication is essential to maintain functions of a healthy host, so defense capacity of hosts is another influence factor, which is thought to combine to determine the result of the fighting. With the development of gene research technology, many human genetic loci were identified to be involved in GI diseases susceptibility, providing more insights into and knowledge about GI diseases. The current review aims to provide an update on the most recent progress in the identification and characterization of bacteria in GI diseases in a variety of organ systems and clinical conditions, and examine the invasion and escape mechanisms of pathogens that have been demonstrated in previous studies, we also review the existing data on the predictive factors of the host, mainly on genetic findings. These strategies may improve our understanding of the mechanisms underlying GI diseases, and open new avenues for the study of the associated conditions in the future.

Oral microbiota in human systematic diseases

Oral bacteria directly affect the disease status of dental caries and periodontal diseases. The dynamic oral microbiota cooperates with the host to reflect the information and status of immunity and metabolism through two-way communication along the oral cavity and the systemic organs. The oral cavity is one of the most important interaction windows between the human body and the environment. The microenvironment at different sites in the oral cavity has different microbial compositions and is regulated by complex signaling, hosts, and external environmental factors. These processes may affect or reflect human health because certain health states seem to be related to the composition of oral bacteria, and the destruction of the microbial community is related to systemic diseases. In this review, we discussed emerging and exciting evidence of complex and important connections between the oral microbes and multiple human systemic diseases, and the possible contribution of the oral microorganisms to systemic diseases. This review aims to enhance the interest to oral microbes on the whole human body, and also improve clinician’s understanding of the role of oral microbes in systemic diseases. Microbial research in dentistry potentially enhances our knowledge of the pathogenic mechanisms of oral diseases, and at the same time, continuous advances in this frontier field may lead to a tangible impact on human health.

The Oral Microbiome in Pediatric IBD: A Source of Pathobionts or Biomarkers?

The oral cavity is continuous with the gastrointestinal tract and in children, oral health may be closely linked with the overall health of the GI tract. In the case of pediatric Crohn's disease (CD), oral manifestations are an important clinical indicator of intestinal disease. Recent studies of the microbiome in IBD suggest that translocation of oral microbes to the gut may be a common feature of the microbial dysbiosis which is a signature of both CD and ulcerative colitis (UC). Murine studies suggest that translocation of oral bacteria and yeasts to the lower GI tract may trigger inflammation in susceptible hosts, providing a mechanistic link to the development of IBD. Conversely, some studies have shown that dysbiosis of the oral microbiome may occur, possibly as a result of inflammatory responses and could represent a useful source of biomarkers of GI health. This review summarizes our current knowledge of the oral microbiome in IBD and presents current hypotheses on the potential role of this community in the pathogenesis of these diseases.

Profiling of Oral Bacterial Communities

The profiling of bacterial communities by the sequencing of housekeeping genes such as that encoding the small subunit ribosomal RNA has revealed the extensive diversity of bacterial life on earth. Standard protocols have been developed and are widely used for this application, but individual habitats may require modification of methods. This review discusses the sequencing and analysis methods most appropriate for the study of the bacterial component of the human oral microbiota. If possible, DNA should be extracted from samples soon after collection. If samples have to be stored for practical reasons, precautions to avoid DNA degradation on freezing should be taken. A critical aspect of profiling oral bacterial communities is the choice of region of the 16S rRNA gene for sequencing. The V1-V2 region provides the best discrimination between species of the genus Streptococcus, the most common genus in the mouth and important in health and disease. The MiSeq platform is most commonly used for sequencing, but long-read technologies are now becoming available that should improve the resolution of analyses. There are a variety of well-established data analysis pipelines available, including mothur and QIIME, which identify sequence reads as phylotypes by comparing them to reference data sets or grouping them into operational taxonomic units. DADA2 has improved sequence error correction capabilities and resolves reads to unique variants. Two curated oral 16S rRNA databases are available: HOMD and CORE. Expert interpretation of community profiles is required, both to detect the presence of contaminating DNA, which is commonly present in the reagents used in analysis, and to differentiate oral and nonoral bacteria and determine the significance of findings. Despite advances in shotgun whole-genome metagenomic methods, oral bacterial community profiling via 16S rRNA sequence analysis remains a valuable technique for the characterization of oral bacterial populations.

Pathogenetic mechanism of oral granulomatous diseases: An update

Oral granulomatous diseases are an intriguing group of lesions characterized by granuloma formation. Mechanisms of granuloma formation differ from disease-to-disease. This article provides an insight into common granulomatous pathogenic mechanisms involving these lesions including immunodeficient states. Understanding various pathogenic mechanisms underlying various granulomatous conditions affecting oral tissues which mainly revolve around inflammatory cells such as macrophages, T lymphocytes, and genetic mutations might aid in devising treatment modalities without having significant side-effects or morbidity in affected subjects.