Journal of Oral Microbiology

OBJECTIVES: Casein kinase 2 interacting protein-1 (CKIP-1) is a versatile player involved in various biological processes. However, whether CKIP-1 mediates the osteogenic/cementogenic differentiation of periodontal ligament cells (PDLCs) under Porphyromonas gingivalis (Pg) stimulation remains unknown. MATERIAL AND METHODS: The effect of Pg on PDLC differentiation was first verified. CKIP-1 expression in Pg-infected PDLCs or in PDL of apical periodontitis (AP) mice was detected...

OBJECTIVES: To evaluate the effect and mechanism of action of the flavonoid phloretin on the growth and sucrose-dependent biofilm formation of Streptococcus mutans . METHODS: Minimum inhibitory concentration, viability, and biofilm susceptibility assays were conducted to assess antimicrobial and antibiofilm effect of phloretin. Biofilm composition and structure were analysed with scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Water-soluble (WSG) and water-insoluble glucan (WIG) were determined using anthrone method...

OBJECTIVES: The oral microbiome is closely associated with systemic diseases, indicating the presence of bacteremia and inflammatory mediators in the systemic circulation. Our research aims to investigate the relationship between the oral microbiome and other microbial habitats. METHODS: We analyzed 180 specimens from 36 patients, including saliva, buccal swab, plaque, stool, and blood samples from a healthy group (Non_PD, n  = 18) and a periodontitis group (PD, n  = 18)...

Gemella species are core members of the human oral microbiome in healthy subjects and are regarded as commensals, although they can cause opportunistic infections. Our objective was to evaluate the site-specialization of Gemella species among various habitats within the mouth by combining pangenomics and metagenomics. With pangenomics, we identified genome relationships and categorized genes as core and accessory to each species. With metagenomics, we identified the primary oral habitat of individual genomes...

Dental unit waterlines (DUWLs) represent a complex environment able to promote microbial contamination, due to functional, mechanical and practical risk factors. According to a water safety plan approach, the main goal is to preserve the health of dentists, dental staff and patients. The aim of this study is to develop a DUWLs water safety plan that is able to support correct and effective maintenance and disinfection procedures. Three different water systems serve 60 dental chairs: (i) water that comes directly from municipal water (Type A), (ii) water supplied by municipal water and water bottles (Type B) and (iii) water supplied only via water bottles (Type C)...

BACKGROUND: Dental caries is a chronic, multifactorial and biofilm-mediated oral bacterial infection affecting almost every age group and every geographical region. Streptococcus mutans is considered an important pathogen responsible for the initiation and development of dental caries. It produces exopolysaccharides in situ to promote the colonization of cariogenic bacteria and coordinate dental biofilm development. OBJECTIVE: The understanding of the regulatory mechanism of S...

Recent studies uncovered that Fusobacterium nucleatum (Fn) , a common, opportunistic bacterium in the oral cavity, is associated with a growing number of systemic diseases, ranging from colon cancer to Alzheimer's disease. However, the pathological mechanisms responsible for this association are still poorly understood. Here, we leverage recent technological advances to study the interactions between Fn and neutrophils. We show that Fn survives within human neutrophils after phagocytosis. Using in vitro microfluidic devices, we determine that human neutrophils can protect and transport Fn over large distances...

We assessed the level of evidence for the presence of new periodontal pathogens by (i) comparing the occurrence of non-classical periodontal taxa between healthy vs. periodontitis patients (Association study); (ii) assessing the modifications in the prevalence and levels of these species after treatments (Elimination study). In the Association study, we compared the prevalence and levels of 39 novel bacterial species between periodontally healthy and periodontitis patients. In the Elimination study, we analyzed samples from periodontitis patients assigned to receive scaling and root planing alone or with metronidazole+ amoxicillin TID/ 14 days...

BACKGROUND: Mfa1 fimbriae of the periodontal pathogen Porphyromonas gingivalis are responsible for biofilm formation and comprise five proteins: Mfa1-5. Two major genotypes, mfa170 and mfa153 , encode major fimbrillin. The mfa170 genotype is further divided into the mfa170A and mfa170B subtypes. The properties of the novel mfa170B remain unclear. METHODS: Fimbriae were purified from P. gingivalis strains JI-1 (mfa170A ), 1439 (mfa170B ), and Ando (mfa153 ), and their components and their structures were analyzed...

BACKGROUND: Comparison of clinical value of RT-qPCR-based SARS-CoV-2 tests performed on saliva samples (SSs) and nasopharyngeal swab samples (NPSs) for prediction of the COVID-19 disease severity. METHODS: Three paired SSs and NPSs collected every 3 days from 100 hospitalised COVID-19 patients during 2020 Jul-2021 Jan were tested by RT-qPCR for the original SARS-CoV-2 virus and compared to 150 healthy controls. Cases were divided into mild+moderate (Cohort I, N  = 47) and severe disease (Cohort II, N  = 53) cohorts and compared...

AIMS: Hemophore-like proteins sequester heme from host hemoproteins. We aimed to determine whether the host immune system can recognize not only Porphyromonas gingivalis HmuY but also its homologs expressed by other periodontopathogens, and how periodontitis influences the production of respective antibodies. METHODS: The reactivity of total bacterial antigens and purified proteins with serum IgG antibodies of 18 individuals with periodontitis and 17 individuals without periodontitis was examined by enzyme-linked immunosorbent assay (ELISA)...

Over the past two decades, the importance of microbiota in health and disease has become evident. The human gut microbiota and oral microbiota are the largest and second-largest microbiome in the human body, respectively, and they are physically connected as the oral cavity is the beginning of the digestive system. Emerging and exciting evidence has shown complex and important connections between gut microbiota and oral microbiota. The interplay of the two microbiomes may contribute to the pathological processes of many diseases, including diabetes, rheumatoid arthritis, nonalcoholic fatty liver disease, inflammatory bowel disease, pancreatic cancer, colorectal cancer, and so on...

Acyl-homoserine lactones (AHLs) are typical quorum-sensing molecules of gram-negative bacteria. Recent evidence suggests that AHLs may also affect gram-positives, although knowledge of these interactions remains scarce. Here, we assessed the effect of AHLs on biofilm formation and transcriptional regulations in the gram-positive Enterococcus faecalis . Five E. faecalis strains were investigated herein. Crystal violet was employed to quantify the biomass formed, and confocal microscopy in combination with SYTO9/PI allowed the visualisation of biofilms' structure...

Decades of ongoing research has established that oral microbial communities play a role in oral diseases such as periodontitis and caries. Yet the detection of oral bacteria and the profiling of oral polymicrobial communities currently rely on methods that are costly, slow, and technically complex, such as qPCR or next-generation sequencing. For the widescale screening of oral microorganisms suitable for point-of-care settings, there exists the need for a low-cost, rapid detection technique. Here, we tailored the novel CRISPR-Cas-based assay SHERLOCK for the species-specific detection of oral bacteria...

BACKGROUND: The oral cavity can be a reservoir for SARS-CoV-2 and may play a crucial role in the viral transmission in the hospital environment. OBJECTIVE: To investigate whether an oral hygiene protocol with chlorhexidine (CHX) used alone and in combination with hydrogen peroxide (HP) in the intensive care unit was effective in reducing the SARS-CoV-2 viral load in the oral cavity. METHODS: SARS-CoV-2 viral load was measured on oral fluid samples collected from patients undergoing orotracheal intubation...

BACKGROUND: Streptococcus mutans ( S. mutans ) is a pivotal cariogenic pathogen contributing to its multiple virulence factors, one of which is synthesizing exopolysaccharides (EPS). VicK, a sensor histidine kinase, plays a major role in regulating genes associated with EPS synthesis and adhesion. Here we first identified an antisense vicK RNA (AS vicK ) bound with vicK into double-stranded RNA (dsRNA). OBJECTIVE: This study aims to investigate the effect and mechanism of AS vicK in the EPS metabolism and cariogenesis of S...

INTRODUCTION: The oral pathogen Porphyromonas gingivalis is not only associated with periodontitis but also with systemic diseases elsewhere in the body. The mechanisms by which P. gingivalis travels from the oral cavity to other organs in the body are largely unknown. This review describes the four putative mechanisms supported by experimental evidence, which enable translocation of P. gingivalis over the oral mucosa, endothelial barriers and subsequent dissemination into the bloodstream...

BACKGROUND: Dysbiosis of oral microbiome causes chronic diseases including dental caries and periodontitis, which frequently affect older patient populations. Severely disabled individuals with impaired swallowing functions may require nutritional supply via nasogastric (NG) tubes, further impacting their oral condition and possibly microbial composition. However, little is known about the effect of NG tube on oral microbes and its potential ramification. METHODS: By using 16S rRNA amplicon sequencing, we characterized the tongue microbiome of 27 patients fed with NG tubes and 26 others fed orally...

Current data on the efficacy of antiseptic mouthwashes to reduce viral load are contradictory. Firstly, in vitro data indicate very strong virucidal effects that are not replicated in clinical studies. Secondly, most clinical studies identify a limited effect, do not include a control/placebo group, or do not evaluate viral viability in an infection model. In the current manuscript, we perform a double-blind, randomized clinical trial where salivary viral load was measured before and after the mouthwash, and where saliva samples were also cultured in an in vitro infection model of SARS-CoV-2 to evaluate the effect of mouthwashes on viral viability...

The oral cavity is an unique ecosystem formed by different structures, tissues, and a complex microbial community formed by hundreds of different species of bacteria, fungi, viruses, phages, and the candidate phyla radiation (CPR) group, all living in symbiosis with healthy individuals. In an opposite state, dental caries is a biofilm-mediated dysbiosis that involves changes in the core microbiome composition and function, which leads to the demineralization of tooth tissues due to the fermentation of dietary carbohydrates, producing acid by select oral bacteria...