Staphylococcus aureus and the oral cavity: an overlooked source of carriage and infection?

Zirconia Dental Implants Surface Electric Stimulation Impact on Staphylococcus aureus

Tooth loss during the lifetime of an individual is common. A strategy to treat partial or complete edentulous patients is the placement of dental implants. However, dental implants are subject to bacterial colonization and biofilm formation, which cause an infection named peri-implantitis. The existing long-term treatments for peri-implantitis are generally inefficient. Thus, an electrical circuit was produced with zirconia (Zr) samples using a hot-pressing technique to impregnate silver (Ag) through channels and holes to create a path by LASER texturing. The obtained specimens were characterized according to vitro cytotoxicity, to ensure ZrAg non-toxicity. Furthermore, samples were inoculated with Staphylococcus aureus using 6.5 mA of alternating current (AC). The current was delivered using a potentiostat and the influence on the bacterial concentration was assessed. Using AC, the specimens displayed no bacterial adhesion (Log 7 reduction). The in vitro results presented in this study suggest that this kind of treatment can be an alternative and promising strategy to treat and overcome bacterial adhesion around dental implants that can evolve to biofilm.

Braided silk sutures coated with photoreduced silver nanoparticles for eradicating Staphylococcus aureus and Streptococcus mutans infections

BACKGROUND

Infections resulting from surgical procedures and wound closures continue to pose significant challenges in healthcare settings. To address this issue, the investigators have developed antibacterial non-resorbable braided silk sutures using in situ deposited silver nanoparticles (AgNPs) and investigated their efficacy in eradicating Staphylococcus aureus and Streptococcus mutans infections.

METHODS

The braided silk sutures were modified through a simple and efficient in situ photoreduction method, resulting in the uniform distribution of AgNPs along the suture surface. The synthesized AgNPs were characterized using scanning electron microscopy (SEM), dynamic light scattering analysis (DLS) and Fourier Transform Infrared Spectroscopy analysis (FTIR) confirming their successful integration onto the silk sutures. The antibacterial activity of the nanoparticle coated sutures were compared and evaluated with non-coated braided silk sutures through in vitro assays against both S. aureus and S. mutans.

RESULTS

The surface and cross-sectional analysis of the treated sutures revealed a uniform and homogeneous distribution of silver particles achieved through the photoreduction of silver solution. This observation confirms the successful coating of silver nanoparticles (AgNPs) on the sutures. The antimicrobial studies conducted, demonstrated significant reductions in bacterial colonies when exposed to the silver nanoparticle-coated sutures. Notably, the width of the inhibition zone surrounding the coated sutures remained consistently wide and stable for duration up to 7 days. This sustained and robust inhibitory effect against gram-positive bacteria, specifically S. aureus and S. mutans, serves as strong evidence of the antibacterial efficacy of the coated sutures.

CONCLUSION

The coating of silk sutures with AgNPs provided a significant and effective antibacterial capacity to the surgical sutures, with this activity being sustained for a period of 7 days. This suggests that AgNPs-in situ photoreduction deposited sutures have the potential to effectively manage S. aureus and S. mutans infections.

Bacterial contamination of air and surfaces during dental procedures-An experimental pilot study using Staphylococcus aureus

OBJECTIVE

The oral cavity contains numerous microorganisms, including antimicrobial-resistant bacteria. These microorganisms can be transmitted via respiratory particles from patients to healthcare providers and vice versa during dental care. We evaluated the spread of Staphylococcus aureus during standardized dental procedures using different scaling devices and rinsing solutions.

METHODS

During systematic therapy for dental biofilm removal (guided biofilm therapy), using an airflow or ultrasound device to a model simulation head. Staphylococcus aureus suspension was injected into the mouth of the model to mimic saliva. Different suction devices (conventional saliva ejector or a prototype) and rising solutions (water or chlorhexidine) were used. To assess contamination with S. aureus, an air-sampling device was placed near the oral cavity and samples of surface areas were collected.

RESULTS

S. aureus was only detected by air sampling when the conventional saliva ejector with airflow was used. No growth was observed during treatments with the ultrasonic piezo instrument or the prototype suction device. Notably, a rinsing solution of chlorhexidine digluconate decreased the bacterial load compared to water. Surface contamination was rarely detected (1 of 120 samples).

CONCLUSIONS

Although our findings indicate potential airborne bacterial transmission during routine prophylactic procedures, specific treatment options during biofilm removal appear to reduce air contamination. These options include ultrasonic piezo devices or the prototype suction device. The use of chlorhexidine reduced the CFU counts of S. aureus detected by air sampling. Surface contamination during dental procedures was a rare occurrence.

Mediterranean diet: a potential player in the link between oral microbiome and oral diseases

Background

The oral microbiome is a complex and dynamic assemblage of microorganisms that colonize different sites of the oral cavity maintaining both oral and systemic health. Therefore, when its composition is altered, oral diseases occur. Among oral inflammatory pathologies, periodontal diseases affect the tissues surrounding the teeth, representing the main cause of tooth loss and one of the most important threats to the oral health. Lifestyle and eating habits influence the composition of the human oral microbiota and the development and progression of oral diseases. In this context, the Mediterranean Diet (MD) model, comprising both healthy dietary choices and lifestyle, is linked to the prevention of several metabolic and chronic-degenerative pathological processes, including oral diseases. Indeed, the MD is a plant-based diet, enriched of anti-inflammatory and antioxidant nutrients, which may induce beneficial effects against dental caries and periodontal diseases.

Aim

This review summarizes the role of the oral microbiome in the development of the oral diseases and the potential of MD in modulating the oral microbiome leading to implications for oral health.

Conclusions

The data collected highlight the need to promote the MD pattern along with the correct hygiene habits to prevent the development of oral diseases.

Investigating the role of Candida albicans as a universal substrate for oral bacteria using a transcriptomic approach: implications for interkingdom biofilm control?

Candida albicans is frequently identified as a colonizer of the oral cavity in health and has recently been termed a "keystone" commensal due to its role on the bacterial communities. However, the role that C. albicans plays in such interactions is not fully understood. Therefore, this study aimed to identify the relationship between C. albicans and bacteria associated with oral symbiosis and dysbiosis. To do this, we evaluated the ability of C. albicans to support the growth of the aerobic commensal Streptococcus gordonii and the anaerobic pathogens Fusobacterium nucleatum and Porphyromonas gingivalis in the biofilm environment. RNA-Sequencing with the Illumina platform was then utilized to identify C. albicans gene expression and functional pathways involved during such interactions in dual-species and a 4-species biofilm model. Results indicated that C. albicans was capable of supporting growth of all three bacteria, with a significant increase in colony counts of each bacteria in the dual-species biofilm (p < 0.05). We identified specific functional enrichment of pathways in our 4-species community as well as transcriptional profiles unique to the F. nucleatum and S. gordonii dual-species biofilms, indicating a species-specific effect on C. albicans. Candida-related hemin acquisition and heat shock protein mediated processes were unique to the organism following co-culture with anaerobic and aerobic bacteria, respectively, suggestive that such pathways may be feasible options for therapeutic targeting to interfere with these fungal-bacterial interactions. Targeted antifungal therapy may be considered as an option for biofilm destabilization and treatment of complex communities. Moving forward, we propose that further studies must continue to investigate the role of this fungal organism in the context of the interkingdom nature of oral diseases.

Infective endocarditis: prevention strategy and risk factors in an animal model

INTRODUCTION

Infective endocarditis is a serious infection of the endocardium, especially the heart valves, which is associated with a high mortality rate. It generally occurs in patients with altered and abnormal cardiac architecture combined with exposure to bacteria from trauma and other potentially high-risk activities with transient bacteremia.

A pattern of microbiological colonization of orthodontic miniscrew implants

INTRODUCTION

Current orthodontic literature reveals a lack of studies on bacterial colonization of orthodontic miniscrew implants (MSI) and their role in the stability of MSI. This study aimed to determine the pattern of microbiological colonization of miniscrew implants in 2 major age groups, to compare it with the microbial flora of gingival sulci in the same group of patients and to compare microbial flora in successful and failed miniscrews.

METHODS

The study involved 102 MSI placed in 32 orthodontic subjects in 2 age groups: (1) aged ≤14 years and (2) aged >14 years. Gingival and peri-mini implant crevicular fluid samples were collected using sterile paper points (International Organization for Standardization no. 35) >3 months and processed by conventional microbiologic culture and biochemical techniques. A microbiologist characterized and identified the bacteria, and the results were subjected to statistical analysis.

RESULTS

Initial colonization was reported within 24 hours, with Streptococci being the dominant colonizer. The relative proportion of anaerobic bacteria over aerobic bacteria increased over time in peri-mini implant crevicular fluid. Group 1 had greater Citrobacter (P = 0.036) and Parvimonas micra (P = 0.016) colonizing MSI than group 2. Failed MSI showed a significantly higher presence of Parvimonas micra (P = 0.008) in group 1 and Staphylococci (P = 0.008), Enterococci (P = 0.011), and Parvimonas micra (P <0.001) in group 2.

CONCLUSIONS

Microbial colonization around MSI is established within 24 hours. Compared to gingival crevicular fluid, peri-mini implant crevicular fluid is colonized by a higher proportion of Staphylococci, facultative enteric commensals and anaerobic cocci. The failed miniscrews showed a higher proportion of Staphylococci, Enterobacter, and Parvimonas micra, suggesting their possible role in the stability of MSI. The bacterial profile of MSI varies with age.

Bacterial exclusion and wound healing potential of horizontal platelet-rich fibrin (H-PRF) membranes when compared to 2 commercially available collagen membranes

OBJECTIVES

The aim of the present study was to compare the barrier function during bacterial invasion and wound healing properties of 3 commonly used membranes including horizontal platelet-rich fibrin (H-PRF) against two commercially available resorbable collagen membranes.

MATERIALS AND METHODS

H-PRF membranes were prepared by collecting venous blood from 3 healthy volunteers using a 700 g for 8-min centrifugation protocol followed by compression into membranes. To evaluate their barrier function, 3 groups (H-PRF membrane, collagen membrane A (Bio-Gide, Geistlich), collagen membrane B (Megreen, Shanxi Ruisheng Biotechnology Co) were placed between an inner chamber and outer chamber and inoculated with S. aureus. At 2 h, 24 h, and 48 h post-inoculation, cultures from the inner and outer chambers were assessed for bacterial CFUs. Then, scanning electron microscope (SEM) was utilized to visualized the morphological destruction by bacteria of the inner and outer surfaces of the membranes. To assess the wound healing properties of each membrane, leachates from each group were applied to human gingival fibroblasts (HGF) and a scratch assay was performed at 24 h and 48 h.

RESULTS

S. aureus showed a minimal bacterial attachment or invasion rate through either collagen membranes at 2 h post-inoculation, yet over time demonstrated rapid degradation, especially on the rougher surface. While PRF demonstrated higher number of CFUs after 2 h, no significant penetration/degradation of the H-PRF membranes was observed at 24 h and 48 h in the H-PRF group. Both collagen membranes demonstrated significant morphological changes 48 h post-bacterial innoculation, while minimal obvious morphological changes were observed in the H-PRF group. The wound healing assay also demonstrated significantly better wound closure rates in the H-PRF group.

CONCLUSION

H-PRF membranes exhibited better barrier function towards S. aureus over 2 days of innoculation and better wound healing ability when compared to two commercially available collagen membranes.

CLINICAL RELEVANCE

This study provides further evidence for the application of H-PRF membranes during guided bone regeneration by minimizing bacterial invasion. Furthermore, H-PRF membranes have significantly better ability to promote wound healing.

Antimicrobial resistance and virulence of subgingival staphylococci isolated from periodontal health and diseases

The dysbiotic biofilm of periodontitis may function as a reservoir for opportunistic human pathogens of clinical relevance. This study explored the virulence and antimicrobial susceptibility of staphylococci isolated from the subgingival biofilm of individuals with different periodontal conditions. Subgingival biofilm was obtained from 142 individuals with periodontal health, 101 with gingivitis and 302 with periodontitis, and cultivated on selective media. Isolated strains were identified by mass spectrometry. Antimicrobial susceptibility was determined by disk diffusion. The mecA and virulence genes were surveyed by PCR. Differences among groups regarding species, virulence and antimicrobial resistance were examined by Chi-square, Kruskal-Wallis or Mann-Whitney tests. The overall prevalence of subgingival staphylococci was 46%, especially in severe periodontitis (> 60%; p < 0.01). S. epidermidis (59%) and S. aureus (22%) were the predominant species across groups. S. condimenti, S. hominis, S. simulans and S. xylosus were identified only in periodontitis. High rates of resistance/reduced sensitivity were found for penicillin (60%), amoxicillin (55%) and azithromycin (37%), but multidrug resistance was observed in 12% of the isolates. Over 70% of the mecA + strains in periodontitis were isolated from severe disease. Higher detection rates of fnB + isolates were observed in periodontitis compared to health and gingivitis, whereas luxF/luxS-pvl + strains were associated with sites with deep pockets and attachment loss (p < 0.05). Penicillin-resistant staphylococci is highly prevalent in the subgingival biofilm regardless of the periodontal status. Strains carrying virulence genes related to tissue adhesion/invasion, inflammation and cytotoxicity support the pathogenic potential of these opportunists in the periodontal microenvironment.

At-Home Saliva Sampling in Healthy Adults Using CandyCollect, a Lollipop-Inspired Device

Respiratory infections are common in children, and there is a need for user-friendly collection methods. Here, we performed the first human subjects study using the CandyCollect device, a lollipop-inspired saliva collection device .We showed that the CandyCollect device can be used to collect salivary bacteria from healthy adults using Streptococcus mutans and Staphylococcus aureus as proof-of-concept commensal bacteria. We enrolled healthy adults in a nationwide (USA) remote study in which participants were sent study packages containing CandyCollect devices and traditional commercially available oral swabs and spit tubes. Participants sampled themselves at home, completed usability and user preference surveys, and mailed the samples back to our laboratory for analysis by qPCR. Our results showed that for participants in which a given bacterium (S. mutans or S. aureus) was detected in one or both of the commercially available methods (oral swab and/or spit tubes), CandyCollect devices had a 100% concordance with the positive result (n = 14 participants). Furthermore, the CandyCollect device was ranked the highest preference sampling method among the three sampling methods by 26 participants surveyed (combining survey results across two enrollment groups). We also showed that the CandyCollect device has a shelf life of up to 1 year at room temperature, a storage period that is convenient for clinics or patients to keep the CandyCollect device and use it any time. Taken together, we have demonstrated that the CandyCollect is a user-friendly saliva collection tool that has the potential to be incorporated into diagnostic assays in clinic visits and telemedicine.

Unveiling the Relevance of the Oral Cavity as a Staphylococcus aureus Colonization Site and Potential Source of Antimicrobial Resistance

Staphylococcus aureus is both a human commensal and a pathogen, that causes serious nosocomial and community-acquired infections. Despite nostrils being considered its preferred host habitat, the oral cavity has been demonstrated to be an ideal starting point for auto-infection and transmission. The antibiotic resistance assessment of S. aureus is a priority and is often reported in clinical settings. This study aimed to explore the prevalence and antimicrobial susceptibility of S. aureus in the oral and nasal cavities of healthy individuals. The participants (n = 101) were subjected to a demographic and clinical background survey, a caries evaluation, and to oral and nasal swabbing. Swabs were cultured in differential/selective media and S. aureus isolates were identified (MALDI-TOF MS) and tested for antibiotic susceptibility (EUCAST/CLSI). Similar S. aureus prevalence was found exclusively on nasal (13.9%) or oral (12.0%) habitats, whereas 9.9% of the population were simultaneous nasal and oral carriers. In oro-nasal cavities, similar antibiotic resistance rates (83.3-81.5%), including MDR (20.8-29.6%), were observed. Notably, 60% (6/10) of the simultaneous nasal and oral carriers exhibited different antibiotic resistance profiles between cavities. This study demonstrates the relevance of the oral cavity as an independent colonization site for S. aureus and as a potential source of antimicrobial resistance, a role which has been widely neglected so far.

The Role of Natural Compounds in Optimizing Contemporary Dental Treatment-Current Status and Future Trends

For a long period of time, natural remedies were the only ailment available for a multitude of diseases, and they have proven effective even after the emergence of modern medicine. Due to their extremely high prevalence, oral and dental disorders and anomalies are recognized as major public health concerns. Herbal medicine is the practice of using plants with therapeutic characteristics for the purpose of disease prevention and treatment. Herbal agents have made a significant entry into oral care products in recent years, complementing traditional treatment procedures due to their intriguing physicochemical and therapeutic properties. There has been a resurgence of interest in natural products because of recent updates, technological advancements, and unmet expectations from current strategies. Approximately eighty percent of the world's population uses natural remedies, especially in poorer nations. When conventional treatments have failed, it may make sense to use natural drugs for the treatment of pathologic oral dental disorders, as they are readily available, inexpensive, and have few negative effects. The purpose of this article is to provide a comprehensive analysis of the benefits and applications of natural biomaterials in dentistry, to gather relevant information from the medical literature with an eye toward its practical applicability, and make suggestions for the directions for future study.

Rapid specific detection of oral bacteria using Cas13-based SHERLOCK

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. We developed a computational pipeline capable of generating constructs suitable for SHERLOCK and experimentally validated the detection of seven oral bacteria. We achieved detection within the single-molecule range that remained specific in the presence of off-target DNA found within saliva. Further, we adapted the assay for detecting target sequences directly from unprocessed saliva samples. The results of our detection, when tested on 30 healthy human saliva samples, fully aligned with 16S rRNA sequencing. Looking forward, this method of detecting oral bacteria is highly scalable and can be easily optimized for implementation at point-of-care settings.

At-home saliva sampling in healthy adults using CandyCollect, a lollipop-inspired device

Respiratory infections are common in children, and there is a need for user-friendly collection methods. Here, we performed the first human subjects study using the CandyCollect device, a lollipop inspired saliva collection device. 1 We showed the CandyCollect device can be used to collect salivary bacteria from healthy adults using Streptococcus mutans and Staphylococcus aureus as proof-of-concept commensal bacteria. We enrolled healthy adults in a nationwide (USA) remote study in which participants were sent study packages containing CandyCollect devices and traditional commercially available oral swabs and spit tubes. Participants sampled themselves at home, completed usability and user preference surveys, and mailed the samples back to our laboratory for analysis by qPCR. Our results showed that for participants in which a given bacterium ( S. mutans or S. aureus ) was detected in one or both of the commercially available methods (oral swab and/or spit tubes), CandyCollect devices had a 100% concordance with the positive result (n=14 participants). Furthermore, the CandyCollect device was ranked the highest preference sampling method among the three sampling methods by 26 participants surveyed (combining survey results across two enrollment groups). We also showed that the CandyCollect device has a shelf life of up to 1 year at room temperature, a storage period that is convenient for clinics or patients to keep the CandyCollect device and use it any time. Taken together, we have demonstrated that the CandyCollect is a user-friendly saliva collection tool that has the potential to be incorporated into diagnostic assays in clinic visits and telemedicine.

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Development of a novel, entirely herbal-based mouthwash effective against common oral bacteria and SARS-CoV-2

BACKGROUND

Parallel to the growth of the oral healthcare market, there is a constantly increasing demand for natural products as well. Many customers prefer products that contain fewer toxic agents, therefore providing an environmentally friendly solution with the benefit of smaller risk to the user. Medieval and early modern medicinal knowledge might be useful when looking for natural, herbal-based components to develop modern products. Along with these considerations we created, tested, and compared an entirely natural mouthwash, named Herba Dei.

METHODS

The manufacturing procedure was standardized, and the created tincture was evaluated by GC/MS analysis for active compounds, experimentally tested in cell-based cytotoxicity, salivary protein integrity, cell-free antioxidant activity, anti-bacterial and anti-viral assays, and compared with three market-leading mouthwashes.

RESULTS

Our tincture did not show significant damage in the cytotoxicity assays to keratinocyte and Vero E6 cells and did not disrupt the low molecular weight salivary proteins. Its radical scavenging capacity surpassed that of two tested, partly natural, and synthetic mouthwashes, while its antibacterial activity was comparable to the tested products, or higher in the bacterial aerobic respiratory assay. The active compounds responsible for the effects include naturally occurring phenylpropanoids, terpenes, and terpenoids. Our mouthwash proved to be effective in vitro in lowering the copy number of SARS-CoV-2 in circumstances mimicking the salivary environment.

CONCLUSIONS

The developed product might be a useful tool to impede the transmission and spread of SARS-CoV-2 in interpersonal contact and aerosol-generating conditions. Our mouthwash can help reduce the oral bacterial flora and has an antioxidant activity that facilitates wound healing and prevents adverse effects of smoke in the oral cavity.

Altered oral microbiome in Sudanese Toombak smokeless tobacco users carries a newly emerging risk of squamous cell carcinoma development and progression

There are an estimated 6-10 million smokeless tobacco (Toombak) users in Sudan, the majority being males. Toombak is known to be a carcinogenic product that is likely to modify the oral microbiome spatiality into a high-risk potential for the development and progression of oral cancer, but previous studies are lacking in this field. Here, we endeavour for the first time the exploration of the oral microbiome in key mucosal areas of the oral cavity and assess the microbiome variations in premalignant and oral squamous cell carcinoma (OSCC) samples from both users and non-users of Toombak. 16S rRNA sequencing was performed on DNA obtained from pooled saliva, oral mucosa and supragingival plaque from 78 Sudanese users and non-users of Toombak, aged between 20 and 70 years. In 32 of the pooled saliva samples, the mycobiome (fungal) environment was analysed through ITS sequencing. Then, 46 formalin-fixed paraffin-embedded samples of premalignant and OSCC samples were collected, and their associated microbiomes sequenced. The oral Sudanese microbiome was found to be enriched in Streptococcaceae, but Staphylococcaceae were significantly more abundant amongst Toombak users. Genera enriched in the oral cavity of Toombak users included Corynebacterium_1 and Cardiobacterium while in non-users, Prevotella, Lactobacillus and Bifidobacterium were prominent. Aspergillus was the most abundant fungus in the mouths of Toombak users with a marked loss of Candida. The genus Corynebacterium_1 was abundant in the buccal, floor of the mouth and saliva microbiomes as well as in oral cancer samples from Toombak users indicating a possible role for this genus in the early stages of oral cancer development. An oral cancer microbiome that favours poor survival and metastasis in those who use Toombak also emerged that includes the genera Stenotrophomonas and Schlegelella. Those utilising Toombak carry an altered oral microbiome that may be an additional risk factor for this products carcinogenicity to the oral structures. These significant microbiome modulations are a newly emerging key driving factor in oral cancer development and progression in Toombak users while it is also shown that Toombak users carry an oral cancer microbiome that may increase the potential for a poorer prognosis.

Formation of a biofilm matrix network shapes polymicrobial interactions

Staphylococcus aureus colonizes the same ecological niche as many commensals. However, little is known about how such commensals modulate staphylococcal fitness and persistence. Here we report a new mechanism that mediates dynamic interactions between a commensal streptococcus and S. aureus. Commensal Streptococcus parasanguinis significantly increased the staphylococcal biofilm formation in vitro and enhanced its colonization in vivo. A streptococcal biofilm-associated protein BapA1, not fimbriae-associated protein Fap1, is essential for dual-species biofilm formation. On the other side, three staphylococcal virulence determinants responsible for the BapA1-dependent dual-species biofilm formation were identified by screening a staphylococcal transposon mutant library. The corresponding staphylococcal mutants lacked binding to recombinant BapA1 (rBapA1) due to lower amounts of eDNA in their culture supernatants and were defective in biofilm formation with streptococcus. The rBapA1 selectively colocalized with eDNA within the dual-species biofilm and bound to eDNA in vitro, highlighting the contributions of the biofilm matrix formed between streptococcal BapA1 and staphylococcal eDNA to dual-species biofilm formation. These findings have revealed an additional new mechanism through which an interspecies biofilm matrix network mediates polymicrobial interactions.

May the force be with you: The role of hyper-mechanostability of the bone sialoprotein binding protein during early stages of Staphylococci infections

The bone sialoprotein-binding protein (Bbp) is a mechanoactive MSCRAMM protein expressed on the surface of Staphylococcus aureus that mediates adherence of the bacterium to fibrinogen-α (Fgα), a component of the bone and dentine extracellular matrix of the host cell. Mechanoactive proteins like Bbp have key roles in several physiological and pathological processes. Particularly, the Bbp: Fgα interaction is important in the formation of biofilms, an important virulence factor of pathogenic bacteria. Here, we investigated the mechanostability of the Bbp: Fgα complex using in silico single-molecule force spectroscopy (SMFS), in an approach that combines results from all-atom and coarse-grained steered molecular dynamics (SMD) simulations. Our results show that Bbp is the most mechanostable MSCRAMM investigated thus far, reaching rupture forces beyond the 2 nN range in typical experimental SMFS pulling rates. Our results show that high force-loads, which are common during initial stages of bacterial infection, stabilize the interconnection between the protein's amino acids, making the protein more "rigid". Our data offer new insights that are crucial on the development of novel anti-adhesion strategies.

An organotypic oral mucosal infection model to study host-pathogen interactions

Early in vitro oral mucosal infection models (OMMs) failed to consider the suitability of the model environment to represent the host immune response. Denture stomatitis (DS) is mediated by Candida albicans, but the role of Staphylococcus aureus remains uncertain. A collagen hydrogel-based OMM containing HaCaT and HGF cell types was developed, characterised and employed to study of tissue invasion and pro-inflammatory cytokine production in response to pathogens. Models formed a robust epithelium. Despite their inflammatory baseline, 24-h infection with C. albicans, and/or S. aureus led to tissue invasion, and significantly upregulated IL-6 and IL-8 production by OMMs when compared to the unstimulated control. No significant difference in IL-6 or IL-8 production by OMMs was observed between single and dual infections. These attributes indicate that this newly developed OMM is suitable for the study of DS and could be implemented for the wider study of oral infection.

The FnBPA from methicillin-resistant Staphylococcus aureus promoted development of oral squamous cell carcinoma

Background

Oral squamous cell carcinoma (OSCC) is the most common tumor in the oral cavity. Methicillin-resistant Staphylococcus aureus (MRSA) were highly detected in OSCC patients; however, the interactions and mechanisms between drug-resistant bacteria (MRSA) and OSCC are not clear.

Aim

The aim of this study was to investigate the promotion of MRSA on the development of OSCC.

Methods

MRSA and MSSA (methicillin-susceptible) strains were employed to investigate the effect on the proliferation of OSCC in vitro and vivo.

Results

All of the MRSA strains significantly increased the proliferation of OSCC cells and MRSA arrested the cell cycles of OSCC cells in the S phase. MRSA activated the expression of TLR-4, NF-κB and c-fos in OSCC cells. MRSA also promoted the development of squamous cell carcinoma in vivo. The virulence factor fnbpA gene was significantly upregulated in all MRSA strains. By neutralizing FnBPA, the promotions of MRSA on OSCC cell proliferation and development of squamous cell carcinoma were significantly decreased. Meanwhile, the activation of c-fos and NF-κB by MRSA was also significantly decreased by FnBPA antibody.

Conclusion

MRSA promoted development of OSCC, and the FnBPA protein was the critical virulence factor. Targeting virulence factors is a new method to block the interaction between a drug-resistant pathogen and development of tumors.

Staphylococcus aureus populations from the gut and the blood are not distinguished by virulence traits-a critical role of host barrier integrity

BACKGROUND

The opportunistic pathogen Staphylococcus aureus is an asymptomatically carried member of the microbiome of about one third of the human population at any given point in time. Body sites known to harbor S. aureus are the skin, nasopharynx, and gut. In particular, the mechanisms allowing S. aureus to pass the gut epithelial barrier and to invade the bloodstream were so far poorly understood. Therefore, the objective of our present study was to investigate the extent to which genetic differences between enteric S. aureus isolates and isolates that caused serious bloodstream infections contribute to the likelihood of invasive disease.

RESULTS

Here, we present genome-wide association studies (GWAS) that compare the genome sequences of 69 S. aureus isolates from enteric carriage by healthy volunteers and 95 isolates from bloodstream infections. We complement our GWAS results with a detailed characterization of the cellular and extracellular proteomes of the representative gut and bloodstream isolates, and by assaying the virulence of these isolates with infection models based on human gut epithelial cells, human blood cells, and a small animal infection model. Intriguingly, our results show that enteric and bloodstream isolates with the same sequence type (ST1 or ST5) are very similar to each other at the genomic and proteomic levels. Nonetheless, bloodstream isolates are not necessarily associated with an invasive profile. Furthermore, we show that the main decisive factor preventing infection of gut epithelial cells in vitro is the presence of a tight barrier.

CONCLUSIONS

Our data show that virulence is a highly variable trait, even within a single clone. Importantly, however, there is no evidence that blood stream isolates possess a higher virulence potential than those from the enteric carriage. In fact, some gut isolates from healthy carriers were more virulent than bloodstream isolates. Based on our present observations, we propose that the integrity of the gut epithelial layer, rather than the pathogenic potential of the investigated enteric S. aureus isolates, determines whether staphylococci from the gut microbiome will become invasive pathogens. Video Abstract.

Acute paronychia in a neonate secondary to clindamycin-resistant Staphylococcus aureus

Paronychia is a common inflammatory condition of the nail fold that is often associated with infection. Causes can be fungal, viral, or most commonly, bacterial. Neonatal paronychia is a rare presentation with only one previously reported case in the literature of a patient younger than 1 month of age. This is a case of an 8-day-old neonate with acute bacterial paronychia caused by clindamycin-resistant Staphylococcus aureus.

Antibacterial Effect of Triazine in Barrier Membranes with Therapeutic Activity for Guided Bone Regeneration

Objective: This study aimed to develop polymer-based barrier membranes based on poly(butylene-adipate-co-terephthalate) (PBAT) with the addition of 1,3,5-triacriloilhexahydro-1,3,5-triazine (TAT). Materials and Methods: Polymeric solutions were used to produce membranes with 5 wt% and 10 wt% of TAT by solvent casting. Membranes without the addition of TAT were used as controls. The membranes were chemically characterized by Fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TGA); surface properties were assessed by profilometry and contact angle; the mechanical behavior was evaluated by a tensile test, and the biological properties were assessed by direct−indirect cell viability and antibacterial activity by S. mutans and S. aureus colony-forming units. Results: TAT was detected in the FTIR and TGA analyses and modified the top surface of the membranes, increasing their roughness and wetness in both concentrations compared to the control group (p < 0.05). The addition of TAT, regardless of concentration, reduced the tensile strength and increased membrane stiffness (p < 0.05). The cell viability of 5 wt% TAT and 10 wt% TAT was 86.37% and 82.36%, respectively. All tested concentrations reduced the formation of biofilm on the membranes when compared to the control. Conclusion: The addition of TAT successfully resulted in the antimicrobial ability of PBAT-based barrier membranes, while it maintained acceptable levels of cell viability in membranes with adequate handling and surface properties.

Antimicrobial and Anti-Biofilm Activities of Thymus fallax Essential Oil against Oral Pathogens

Aim. Oral infections associated with a wide diversity of microorganisms, including bacteria and yeasts, occur frequently in humans, affecting the whole oral cavity and well-being. Oral pathogens easily grow and propagate in the oral cavity, leading to the formation of dental plaque on both soft and hard tissue. The oral cavity contains up to 700 different species of microorganisms, which Candida and Streptococci are the most common organisms. Oral diseases continue to increase despite the best efforts of the medical and scientific communities. During the past decades, drug resistance to common antibiotics used in the treatment of oral infections has been raised to high levels worldwide. To overcome such resistance, there is a growing tendency to use herbal medicine as alternative. This study was conducted to find out the chemical constitution of Thymus fallax (T. fallax) essential oil and to determine its antimicrobial and anti-biofilm efficacy against common oral pathogens. Materials and Methods. The chemical compositions of the essential oil distilled from T. fallax plants were analyzed using gas chromatography/mass spectrometry (GC/MS). Antimicrobial susceptibility testing against common Streptococcus, Enterococcus, Staphylococcus, and Candida strains was assessed by broth microdilution in 96-well plates as suggested by the Clinical and Laboratory Standards Institute (CLSI) methods. Biofilm growth and development were assessed using XTT reduction assay. Results. Based on the GC/MS test results, thymol (67.75%) followed by caryophyllene (E-) (7.27%) was the main component of this essential oil. T. fallax inhibited the growth of examined microbial pathogens at concentrations of 0.031-16 μL/mL. Also, the essential oil showed biofilm inhibition of greater than 95% in the concentration of 8 μL/mL against all tested bacterial strains as well as Candida albicans ( $p$ value < 0.05). Conclusions. Considering the significant antimicrobial activities of T. fallax, this essential oil has the potential to be used as further antimicrobial and anti-biofilm pharmaceutical products in the control and treatment of oral infections.

Fabrication and Optimization of Essential-Oil-Loaded Nanoemulsion Using Box-Behnken Design against Staphylococos aureus and Staphylococos epidermidis Isolated from Oral Cavity

Oral bacterial infections are fairly common in patients with diabetes mellitus; however, due to limited treatment options, herbal medicines are considered an alternate solution. This study aimed to formulate a stable essential-oil-loaded nanoemulsion for the treatment of oral bacterial infections. Essential oils from edible sources including coriander, clove, cinnamon and cardamom were extracted by hydrodistillation. The response surface methodology was used to optimize the nanoemulsion formulation by applying the Box–Behnken design. The oil concentration, surfactant concentration and stirring speed were three independent factors, and particle size and polydispersity index were two responses. The particle size, polydispersity index and zeta potential of the optimized formulation were 130 mm, 0.222 and −22.9, respectively. The ATR-FTIR analysis revealed that there was no incompatibility between the active ingredients and the excipients. A significant release profile in active ingredients of nanoemulsion, i.e., 88.75% of the cinnamaldehyde and 89.33% of eugenol, was recorded after 24 h. In the ex vivo goat mucosal permeation study, 71.67% of the cinnamaldehyde permeated and that of the eugenol 70.75% from the nanoemulsion. The optimized formulation of the essential-oil-loaded nanoemulsion showed a 9 mm zone of inhibition against Staphylococcus aureus and Staphylococcus epidermidis, whereas in anti-quorum sensing analysis, the optimized nanoemulsion formulation showed an 18 mm zone of inhibition. It was concluded that formulated essential-oil-loaded nanoemulsion can be used against S. epidermidis and S. aureus infections in oral cavity.

Candidiasis and Other Bacterial Infections among Patients Diagnosed with Burning Mouth Syndrome

Background and Objectives: Burning mouth syndrome (BMS) is a state in which a patient experiences intraoral burning or a dysesthetic sensation without clinically evident causative lesions in the oropharyngeal area. The disorder is linked to a variety of conditions, including dry mouth, Candida, and bacterial infections. The aim of this study was to determine the incidence of oral Candida and/or bacterial infections among patients with BMS and whether they have an effect on pain/burning and salivary flow levels. Objectives: (1) Gather patient data regarding the presence of oral infections, dry mouth, and pain levels in the morning, afternoon, and evening periods; (2) data analysis and assessment to determine medians, means, frequencies, correlations, and statistically significant differences between patient groups. Materials and Methods: Overall, 173 patients (23 males and 150 females) with BMS and 13 controls (five males and eight females) took part in the study. We measured pain/burning levels, unstimulated and stimulated salivary flow, the percentage of patients infected with Candida species and/or bacterial species, and the said species growth in Petri dishes. Results: Candida albicans was the most commonly found infection among patients with BMS (n = 28, 16.2%). Overall, 21.4% patients with BMS were diagnosed with either C. albicans or another Candida species. Enterobacter had the richest growth among patients with BMS (7.5% out of the infected 10.4% BMS patients). No statistical significance could be noted between the existence of either Candida species or bacterial species infections and changes in pain/burning and salivary flow levels. Negative correlations were noted between age and unstimulated and stimulated salivary flow, and positive correlations were noted between age and Candida andspecific bacteria species’ growth levels. Conclusions: Although patients with present bacterial or Candida infections showed a marginal increase in pain/burning levels, no direct statistically significant associations could be made between the presence of Candida species or other bacteria and the symptoms among patients with BMS.

Is the Oral Cavity of Intensive Care Unit Pediatric Patients More Susceptible to Methicillin-Resistant Staphylococcus aureus Infection?

Objective: The aim of this study was to assess the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the oral cavity of pediatric patients hospitalized at an intensive care unit (ICU). Methodology: Thirty ICU patients (group 1) and 30 healthy patients (group 2), between 1 and 12 years of age, matched by sex and age, were selected from a public hospital in Brazil. After oral examinations, biological specimens (nostril swab, oral mucosa, and supragingival biofilm) were collected from both groups to verify the presence of Staphylococcus aureus. Identification occurred after growth in Tryptic Soy Broth with 7.5% of NaCl for 48 hours, growth in Mannitol Salt Agar, gram staining, catalase, and coagulase tests. S. aureus isolates were submitted to antibiotic sensitivity test. Results: Only 36.7% of patients in the ICU perform oral hygiene during the hospitalization period and 41.7% presented high level of dental biofilm accumulation. The presence of S. aureus was similar in patients from group 1 (43.3%, 13) and group 2 (50.0%, 15) (p = 0.60). Both groups presented 18 samples each that tested positive for S. aureus. However, when considering patients infected by MRSA, the prevalence was higher in group 1 (eight; 26.7%) than in group 2 (five; 16.7%) but no statistical difference was observed (p = 0.53). In group 1, nine MRSA samples were resistant to erythromycin and seven to clindamycin. In group 2, two MRSA samples were resistant to erythromycin and two to clindamycin. Conclusions: Although ICU children did not show a significant higher carriage of MRSA when compared with the healthy group in the population studied, the number of highly resistant strains in the oral cavity isolated from ICU patients adds an important risk factor to be considered by the medical team as possible source of systemic infections, extended hospital stay, and poor outcomes.

Thrombus-associated microbiota in acute ischemic stroke patients

Background:

Despite a reduction in stroke incidence and age-standardized death rates, stroke remains a leading cause of death and disability worldwide. Significant interest in recent years has focused on the microbiota-host interaction because accumulating evidence has revealed myriad ways in which bacteria may contribute to risk of stroke and adverse outcomes after stroke. The emergence of endovascular thrombectomy as a treatment provides a unique opportunity to utilize thrombus retrieved from cerebral arteries to fill knowledge gaps about the influence of bacteria on stroke pathophysiology. While bacterial signatures have been confirmed in cerebral thrombi, the exact nature of the pathogenesis has not been established.

Methods:

Thrombi were obtained from a cohort of adult ischemic stroke patients during standard of care thrombectomy. After DNA extraction and quantification, thrombi underwent 16S rRNA amplicon-based metagenomic sequencing, followed by bioinformatics processing. Taxonomic identification of bacterial colonies isolated on Agar plates from plated suspension was performed using DNA extraction and full length 16S Sanger sequencing.

Results:

A broad diversity of bacterial signatures was identified in specimens, primarily of cariogenic origin.

Conclusion:

In this small study, we demonstrate proof of concept and technical feasibility for amplicon-based metagenomic sequencing of arterial thrombi and briefly discuss preliminary findings, challenges, and near-term translational opportunities for thrombus genomics.

Inhibitory effects of a water-soluble jujube polysaccharide against biofilm-forming oral pathogenic bacteria

Oral diseases caused by infectious pathogens raises significant concerns in public health. In the light of side effects of current antibiotics therapy and growing drug resistance of pathogenic bacteria, natural products have become attractive alternatives for antibiotics agents in dental practice. This current study investigated the effects of polysaccharides extracted from Zizyphus jujuba Mill. on three major oral biofilm-forming pathogenic bacteria including caries-inducing Streptococcus mutans, lesions-causing MRSA, and periodontitis-related Porphyromonas gingivalis, as well as general oral microbiota. Our results demonstrated that jujube polysaccharide prepared in this study was mainly composed by galacturonic acid with an average molecular weight 242 kDa, which were further characterized for structural features by FT-IR spectra and NMR spectroscopy analysis. This jujube polysaccharide was shown to exhibit remarkable inhibitory effects against all the tested oral bacterial pathogens through various mechanisms including growth inhibition, biofilm prevention and disruption, intervention of bacterial infection (adhesion and invasion), attenuation of cytotoxicity, modulation of excessive inflammatory response of LPS-stimulated and MRSA-infected macrophages as well as positive regulation of oral microbiota. The present study paves the way to explore jujube polysaccharides for the prevention and treatment of oral infectious diseases. Graphic Abstract.

A Comparison of the Adaptive Response of Staphylococcus aureus vs. Streptococcus mutans and the Development of Chlorhexidine Resistance

Antimicrobials with nonselective antibacterial efficacy such as chlorhexidine can be effective in reducing biofilm, but bear the risk of inducing resistance in specific bacteria. In clinical practice, bacteria such as Staphylococcus aureus have been found resistant to chlorhexidine, but other bacteria, including Streptococcus mutans, have largely remained susceptible to chlorhexidine despite its widespread use in oral healthcare. Here, we aim to forward a possible reason as to why S. aureus can acquire resistance against chlorhexidine, while S. mutans remains susceptible to chlorhexidine. Measurement of surface-enhanced fluorescence indicated that chlorhexidine caused gradual, but irreversible deformation to adhering green fluorescent S. aureus due to irreparable damage to the cell wall. Concurrently, the metabolic activity of adhering staphylococci was higher than of planktonic bacteria, suggesting efflux mechanisms may have been activated upon cell wall deformation, impeding the buildup of a high chlorhexidine concentration in the cytoplasm and therewith stimulating the development of chlorhexidine resistance in S. aureus. Exposure of S. mutans to chlorhexidine caused immediate, but reversible deformation in adhering streptococci, indicative of rapid self-repair of cell wall damage done by chlorhexidine. Due to cell wall self-repair, S. mutans will be unable to effectively reduce the chlorhexidine concentration in the cytoplasm causing solidification of the cytoplasm. In line, no increased metabolic activity was observed in S. mutans during exposure to chlorhexidine. Therewith, self-repair is suicidal and prevents the development of a chlorhexidine-resistant progeny in S. mutans.

Preparation of Nano-Apatite Grafted Glass-Fiber-Reinforced Composites for Orthodontic Application: Mechanical and In Vitro Biofilm Analysis

This study aimed to fabricate nano-hydroxyapatite (nHA) grafted/non-grafted E-glass-fiber-based (nHA/EG) and E-glass fiber (EG) orthodontic retainers and to compare their properties with commercially available retainers. Stainless-steel (SS) retainers and everStick Ortho (EST) were used as control groups. The retainers were evaluated with Raman spectroscopy and bonded to bovine teeth. The samples were fatigued under cyclic loading (120,000 cycles) followed by static load testing. The failure behavior was evaluated under an optical microscope and scanning electron microscope. The strain growth on the orthodontic retainers was assessed (48h and 168h) by an adhesion test using Staphylococcus aureus and Candida albicans. The characteristic peaks of resin and glass fibers were observed, and the debonding force results showed a significant difference among all of the groups. SS retainers showed the highest bonding force, whereas nHA/EG retainers showed a non-significant difference from EG and EST retainers. SS retainers’ failure mode occurred mainly at the retainer–composite interface, while breakage occurred in glass-fiber-based retainers. The strains’ adhesion to EST and EG was reduced with time. However, it was increased with nHA/EG. Fabrication of nHA/EG retainers was successfully achieved and showed better debonding force compared to other glass-fiber-based groups, whereas non-linear behavior was observed for the strains’ adhesion.

The Role of the Oral Immune System in Oropharyngeal Candidiasis-Facilitated Invasion and Dissemination of Staphylococcus aureus

Candida albicans and Staphylococcus aureus account for most invasive fungal and bacterial bloodstream infections (BSIs), respectively. However, the initial point of invasion responsible for S. aureus BSIs is often unclear. Recently, C. albicans has been proposed to mediate S. aureus invasion of immunocompromised hosts during co-colonization of oral mucosal surfaces. The status of the oral immune system crucially contributes to this process in two distinct ways: firstly, by allowing invasive C. albicans growth during dysfunction of extra-epithelial immunity, and secondly following invasion by some remaining function of intra-epithelial immunity. Immunocompromised individuals at risk of developing invasive oral C. albicans infections could, therefore, also be at risk of contracting concordant S. aureus BSIs. Considering the crucial contribution of both oral immune function and dysfunction, the aim of this review is to provide an overview of relevant aspects of intra and extra-epithelial oral immunity and discuss predominant immune deficiencies expected to facilitate C. albicans induced S. aureus BSIs.

Benefits and Implications of Resveratrol Supplementation on Microbiota Modulations: A Systematic Review of the Literature

Resveratrol is a polyphenol that has been shown to possess many applications in different fields of medicine. This systematic review has drawn attention to the axis between resveratrol and human microbiota, which plays a key role in maintaining an adequate immune response that can lead to different diseases when compromised. Resveratrol can also be an asset in new technologies, such as gene therapy. PubMed, Cochrane Library, Scopus, Web of Science, and Google Scholar were searched to find papers that matched our topic dating from 1 January 2017 up to 18 January 2022, with English-language restriction using the following Boolean keywords: (“resveratrol” AND “microbio*”). Eighteen studies were included as relevant papers matching the purpose of our investigation. Immune response, prevention of thrombotic complications, microbiota, gene therapy, and bone regeneration were retrieved as the main topics. The analyzed studies mostly involved resveratrol supplementation and its effects on human microbiota by trials in vitro, in vivo, and ex vivo. The beneficial activity of resveratrol is evident by analyzing the changes in the host’s genetic expression and the gastrointestinal microbial community with its administration. The possibility of identifying individual microbial families may allow to tailor therapeutic plans with targeted polyphenolic diets when associated with microbial dysbiosis, such as inflammatory diseases of the gastrointestinal tract, degenerative diseases, tumors, obesity, diabetes, bone tissue regeneration, and metabolic syndrome.

Antibacterial activity of Medan Butterfly pea (Clitoria ternatea L.) corolla extract against Streptococcus mutans ATCC®25175™ and Staphylococcus aureus ATCC®6538™

Streptococcus mutans (S. mutans) and Staphylococcus aureus (S. aureus) pathogenicity that alter biofim, has become one of risk factor in orthodontic treatment. The medicinal plant’s Butterfly pea efficacy as an antibacterial agent should be confirmed in dentistry. The purpose of this study is to investigate the antibacterial activity of Medan butterfly pea corolla extract (BPCE) against S. mutans ATCC®25175™ and S. aureus ATCC®6538™. This is a laboratory experiment with Post Test Only Group Design. The minimum inhibitory concentration of BPCE is 6.25 mg/mL. The best concentration of butterfly pea extract to inhibit biofilm formation (antibiofilm) is 100 mg/mL. There was a significant difference (p &lt; 0.05) for antibiofilm activity assays and determination of intramembrane cellular leakage. Although Medan BPCE was inadequate enough in forming antibiofilm and caused intramembrane leakage of S. mutans and S. aureus, further studies in exploring the potential morphological traits of these herbs related to orthodontic products are quite promising.

Preliminary Novel Analysis on Antimicrobial Properties of Concentrated Growth Factor against Bacteria-Induced Oral Diseases

OBJECTIVE

 Concentrated growth factor (CGF) is particularly gaining acceptance and popularity in regenerative dentistry. Nonetheless, there are no available studies showing its effect against microorganisms of oral cavity particularly in chronic oral disease-induced biofilms. This in vitro research was conducted to determine the antimicrobial effects of CGF against Staphylococcus aureus sp. (S. aureus) and Streptococcus mutans sp. (S. mutans).

MATERIALS AND METHODS

 Blood samples were obtained from a healthy volunteer. CGF was then prepared using specialized centrifugation equipment (Medifuge, Silfradent, Santa Sofia FC, Italy) and protocol. Antimicrobial activity of the CGF was observed and recorded on standard strains of S. aureus and S. mutans using a well diffusion method to determine the inhibition zone, broth microdilution to determine minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), and crystal violet assay for biofilm assessment, with chlorhexidine (CHX) 0.12% used as a positive control. Statistical analysis was then performed using one-way analysis of variance followed by Tukey Test post hoc analysis.

RESULTS

 It was observed that there was a presence of clear zones of inhibition around the CGF after 24 hours of incubation. The mean diameter of the inhibition zone was 1.26 ± 0.12 nm and 1.20 ± 0.06 nm for S. aureus and S. mutans, respectively, with significance difference (p < 0.05) against the control group CHX 0.12%. The MIC values of the CGF against S. aureus and S. mutans were 47.9% and 34.17%, respectively, and the MBC values of the CGF against S. aureus and S. mutans were 100%. The viability and the ability in inhibiting the biofilm formation of S. mutans and S. aureus following treatment with CGF showed a reduction in the concentration-dependent manner as compared with the control group.

CONCLUSION

 CGF possesses antimicrobial and antibiofilm activity against S. aureus and S. mutans.

Catechin/β-cyclodextrin complex modulates physicochemical properties of pre-gelatinized starch-based orally disintegrating films

The study aimed to develop pre-gelatinized starch-based orally disintegrating films (ODFs) containing catechin/β-cyclodextrin (CAT/β-CD) complex and to evaluate the influence of the complex on the physicochemical properties of the ODFs. SEM images showed that a compacter and more homogeneous ODFs were formed due to interactions between starch matrix and CAT/β-CD. FTIR spectra demonstrated that the interactions between starches or starch and CAT/β-CD were enhanced by hydrogen bonds. Thermal stability of ODFs was improved by incorporating CAT/β-CD, its peak decomposition temperature was enhanced from 310.74 to 321.83 °C. Tensile strength was increased from 11.597 ± 0.153 to 22.172 ± 0.752 MPa, while elongation at break decreased by from 11.233% ± 1.079% to 3.633% ± 0.058%. The prepared ODFs have an acceptable in vitro disintegration time, which were between 9.03 ± 0.79 s and 42.23 ± 1.76 s. Antimicrobial test showed that ODFs incorporating CAT/β-CD inhibited the growth of S. aureus and S. mutans successfully. The limited release of CAT molecules from the ODFs was also found. In addition, the ODFs have excellent antioxidant capacity. Its antioxidant activity remained at around 70% after 28 days of storage. The study indicated that the combination of ODFs and β-CD complex have a high potential for the delivery of natural active ingredients.

The impact of dental care intervention on ventilator-associate events: A Quasi-experimental study

BACKGROUND

This study aimed to evaluate a multidisciplinary intensive oral health protocol, proposed and applied by a dentist, in an adult Intensive Care Unit (ICU), in regards to the prevention of Ventilator-associated Pneumonia (VAP), compared with retrospective data.

METHODS

4,103 patients admitted to the adult ICU from January 2013 to December 2017 and selected patients who were under mechanical ventilation with an orotracheal tube for at least 48 hours. These patients were compared before (Baseline Group) and after (Intervention Group) the hygiene protocol established and carried out by a multidisciplinary team led by a dentist. The Baseline Group, from January 2013 to May 2015, 213 patients, and the Intervention Group, from June 2015 to December 2017, 137 patients.

RESULTS

Forty-five patients (21.12%) in the Baseline Group and 5 patients (3.65%) in the Intervention Group developed VAP (P < .05). Twenty-two patients (10.33%) died due to VAP in the Baseline Group, and 1 patient (0.73%) died due to VAP (P < .05) in the Intervention Group. The mortality rate of  VAP was 48.89% for Baseline Group and 20.00% for Intervention Group (P > .05).

CONCLUSIONS

The study showed better outcomes when patients' oral health is led, evaluated and treated by a dentist in the ICU. The dental care intervention contributed to the reduction of VAP episodes and deaths due to VAP.

Lipid Nanocarriers-Loaded Nanocomposite as a Suitable Platform to Release Antibacterial and Antioxidant Agents for Immediate Dental Implant Placement Restorative Treatment

Immediate implant placement is a single-stage restorative approach for missing teeth widely used to overcome the ridge remodeling process occurring after dental extractions. The success of this procedure relies on opportune osseointegration in the surrounding tissues. To support this process, a multifunctional nanocomposite, to be applied in the fresh post-extraction socket, was here designed, prepared, and characterized. This formulation consists of quercetin (QRC)-loaded nanostructured lipid carriers (NLCs) entrapped in a chitosan-based solid matrix containing ciprofloxacin (CPX). QRC-NLCs were prepared by homogenization followed by high-frequency sonication, and thereafter this dispersion was trapped in a chitosan-based CPX-loaded gel, obtaining the nanocomposite powder (BioQ-CPX) by lyophilization. BioQ-CPX displayed desirable properties such as high porosity (94.1 ± 0.5%), drug amounts (2.1% QRC and 3.5% CPX). and low swelling index (100%). Moreover, the mechanism of drug release from BioQ-CPX and their ability to be accumulated in the target tissue were in vitro and ex vivo elucidated, also by applying mathematical models. When trapped into the nanocomposite, QRC stressed under UV light exposure (50 W) was shown to maintain its antioxidant power, and CPX and QRC under natural light were stable over nine months. Finally, both the measured antioxidant power and the antimicrobial and antibiofilm properties on Staphylococcus aureus demonstrated that BioQ-CPX could be a promising platform to support the single-stage dental restorative treatment.

Dysbiosis in salivary bacterial diversity of postpartum females and its association with oral health problems and APOs

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In present study, salivary microbial diversity of postpartum females was compared with nonpregnant females.

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Microbial colonization was raised in postpartum females especially those having oral health issues.

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Isolated bacterial species showed enhanced biofilm forming and multi drug resistance.

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Alpha diversity was decrease in postpartum female having oral health issues with PLWB.

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Bray-Curtis dissimilarity was highest between females with dental issues and different pregnancy outcomes.

The present study investigates the dysbiosis in salivary bacterial diversity by culture-dependent and independent methods. Culturable aerobic and facultative anaerobic bacterial diversity was studied in saliva collected from 267 postpartum and 54 nonpregnant females by using standard microbiological methods. For unculturable bacterial diversity, DNA from saliva samples of four selected females was sequenced by targeting V4 region of 16S rRNA. In postpartum females, S. mutans was significantly more prevalent. Its colonization was also seen significant among females having gingivitis (P < 0.01), dental caries (P < 0.01), and in those giving birth to low weight baby. In postpartum group, 65.16% females were culture positive for Staphylococcus, 12.73% Gram positive rods, 10.48% N. meningitides, 6.36% K. pneumoniae, 5.61% Enterobacter species and 2.62% E. coli. Isolates showed high biofilm forming ability and antibiotic resistance. Upon analysis of unculturable bacterial diversity, a total of 16 phyla and 156 genera were observed. Alpha diversity was decrease in postpartum female having oral health issues with pre-term low weight birth, compared to females with full term birth. Bray-Curtis dissimilarity was highest between female with dental issues and different pregnancy outcomes. Bacterial diversity and abundance altered among females with different oral health conditions and pregnancy outcomes, and also have pathogenic potential.

An Orthopedic Surgeon's Dental Examination: Reducing Unnecessary Delays in Joint Replacement Surgery for Marginalized Patients in a Safety Net Hospital System

Background

Selective dental clearance before total joint arthroplasty (TJA) has been proposed; however, effective strategies of carrying out this practice are lacking. This study aims to determine the positive predictive value (PPV) of a novel oral examination performed by an orthopedic surgeon to better direct limited resources for marginalized patients in a safety net hospital system.

Methods

A retrospective review was conducted on 105 consecutive patients who had an oral examination performed by a single surgeon before elective TJA. Patients who screened negative proceeded to surgery without further formal dental clearance. Patients who screened positive underwent formal examination/intervention by a dentist before surgery. The rate of correct referral that resulted in patients undergoing an oral surgical intervention was determined. Complications during a minimum 90-day postoperative follow-up period were collected and compared.

Results

Thirty patients (28.6%) screened positive while 75 patients (71.4%) screened negative and proceeded to surgery without referral. The PPV of the screening test was high, with 73.3% of patients receiving a major surgical oral intervention before TJA. Patients sent for formal referral required 89.1 more days to receive their surgery than those that screened negative (54.9 days ± 4.24 vs 144.0 days ± 82.4, P < .001).

Conclusion

An orthopedic surgeon’s oral examination demonstrates a high PPV to identify high-risk patients in need of an oral surgical intervention before TJA. This provides a unique solution regarding over-referral for preoperative dental clearance and avoids delays for marginalized patients considering elective TJA in a safety net hospital system.

Antimicrobial Resistance and Molecular Epidemiological Characteristics of Methicillin-Resistant and Susceptible Staphylococcal Isolates from Oral Cavity of Dental Patients and Staff in Northern Japan

The acquisition of drug resistance and virulence by staphylococcal species colonizing humans is a growing public health concern. The present study was conducted to investigate the prevalence, antimicrobial resistance and genetic characteristics of Staphylococcus isolates from the oral cavity and skin (hand) of systemically healthy subjects with dental disease and dental staff in northern Japan. Among a total of 133 subjects (91 patients and 42 staff), 87 coagulase-positive Staphylococcus (83 S. aureus/4 S. argenteus) and 162 coagulase-negative Staphylococcus (CoNS) isolates were recovered from 59 (44.4%) and 95 (71.4%) subjects, respectively. Three oral isolates were methicillin-resistant S. aureus (MRSA) (3.6%, 3/83) that were genotyped as ST8-SCCmec-IVl, ST4775(CC1)-SCCmec-IVa and ST6562(CC8)-SCCmec-IVa. Remarkably, the ST6562 isolate harbored PVL genes on ΦSa2usa and type I ACME (arginine catabolic mobile element). Four methicillin-susceptible isolates were identified as S. argenteus belonging to ST1223 and ST2250, which harbored enterotoxin genes egc-2 and sey, respectively. Among the fourteen CoNS species identified, methicillin-resistant (MR) isolates were detected in five species (11 isolates, 13.3% of CoNS), with S. saprophyticus and S. haemolyticus being the most common. ACME was prevalent in only S. epidermidis and S. capitis. These findings indicated the potential distribution of USA300 clone-like MRSA, toxigenic S. argenteus and MR-CoNS in the oral cavity of dental patients.

Bacterial Exposure to Nickel: Influence on Adhesion and Biofilm Formation on Orthodontic Archwires and Sensitivity to Antimicrobial Agents

The presence of nickel could modify bacterial behavior and susceptibility to antimicrobial agents. Adhesion and biofilm formation on orthodontic archwires can be a source of bacterial colonization and possible health hazards. Staphylococcus aureus was subjected to exposure and adaptation to various sub-inhibitory concentrations of nickel. Five strains of bacteria adapted to nickel in concentrations of 62.5-1000 μg/mL were tested for adhesion and biofilm formation on nickel-titanium archwires. Archwires were previously incubated in artificial saliva. Bacteria were incubated with orthodontic wire with stirring for 4 h (adhesion) and 24 h (biofilm formation). The number of adherent bacteria was determined after sonication and cultivation on the Muller-Hinton agar. Disk diffusion method was performed on all bacteria to assess the differences in antimicrobial susceptibility. Bacteria adapted to lower concentrations of nickel adhered better to nickel-titanium than strains adapted to higher concentrations of nickel (p < 0.05). Biofilm formation was highest in strains adapted to 250 and 500 μg/mL of nickel (p < 0.05). The highest biofilm biomass was measured for strains adapted to 250 μg/mL, followed by those adapted to 1000 μg/mL. Bacteria adapted to lower concentrations of nickel demonstrated lower inhibition zone diameters in the disk diffusion method (p < 0.05), indicating increased antimicrobial resistance. In conclusion, bacteria adapted to 250 μg/mL of nickel ions adhered better, demonstrated higher biofilm formation and often had higher antimicrobial resistance than other adapted and non-adapted strains.

Antimicrobial Activity of Xibornol and a Xibornol-Based Formulation Against Gram-Positive Pathogens of the Respiratory Tract

Xibornol is known since the 70s and a xibornol-based formulation is commercialized as spray suspension for the antisepsis of the oral cavity and as adjuvant in pharyngeal infections caused by Gram-positive microorganisms. Herein, we evaluated the antimicrobial activity of xibornol and the xibornol-based formulation against common pathogens of the upper and lower respiratory tract.Our results indicate that xibornol alone and the xibornol-based formulation have strong antibacterial action against Streptococcus pneumoniae, Streptococcus pyogenes, and Staphyloccus aureus, as well as against the two emerging pathogens Actinomyces israelii and Corynebacterium ulcerans. These findings highlight the antimicrobial potential of these drugs in the topical control of pathogenic Gram-positive bacteria of the respiratory tract.

Staphylococcal trafficking and infection - from 'nose to gut' and back

Staphylococcus aureus is an opportunistic human pathogen, which is a leading cause of infections worldwide. The challenge in treating S. aureus infection is linked to the development of multidrug-resistant strains and the mechanisms employed by this pathogen to evade the human immune defenses. In addition, S. aureus can hide asymptomatically in particular ‘protective’ niches of the human body for prolonged periods of time. In the present review, we highlight recently gained insights in the role of the human gut as an endogenous S. aureus reservoir next to the nasopharynx and oral cavity. In addition, we address the contribution of these ecological niches to staphylococcal transmission, including the roles of particular triggers as modulators of the bacterial dissemination. In this context, we present recent advances concerning the interactions between S. aureus and immune cells to understand their possible roles as vehicles of dissemination from the gut to other body sites. Lastly, we discuss the factors that contribute to the switch from colonization to infection. Altogether, we conclude that an important key to uncovering the pathogenesis of S. aureus infection lies hidden in the endogenous staphylococcal reservoirs, the trafficking of this bacterium through the human body and the subsequent immune responses.

Characterization and Selection of Lactobacillus plantarum and Lactobacillus paracasei for prevention of oral bacterial infections from Chinese pickle

The oral infections were mainly caused by Streptococci and Staphylococcus aureus. Antibiotic therapies can eliminate these harmful bacteria. However, it can break beneficial microbes and lead to the persistence of resistant strains. The objective of our study was to select potential probiotic strains for the prevention of oral bacterial infections and evaluate their potential probiotic properties in oral cavity. AR113 (Lactobacillus plantarum) and AR340 (Lactobacillus paracasei) with significantly antimicrobial β-hemolytic streptococci and Staphylococcus aureus activity were isolated from Chinese pickle through agar well diffusion assay. Through the analyses of probiotic properties in antibiofilm, lysozyme and hydrogen peroxide tolerance, bacterial surface properties, adherence ability, tooth degradation and anti-inflammatory activity, the AR113 and AR340 showed anti-adhesion activity of 45.2-71.1% and 20.3-56.8% against β-hemolytic streptococci and 15.4-52.6% and 30.7-65.9% against Staphylococcus aureus, respectively, at different concentration. The two strains with high hydrophobicity, autoaggregation and survival rate adhered strongly to FaDu cells. AR113 and AR340 exhibited low calcium released from teeth (0.04 μg/mL and 0.03 μg/mL, respectively). ELISA analysis showed that AR113 and AR340 significantly inhibited the LPS-induced increase of NO and TNF-α expression. Strains-fermented skim milk inhibited the growth of β-hemolytic streptococci or Staphylococcus aureus. AR113 and AR340 were considered as probiotic candidates because of their higher antibacterial activity against some oral pathogenic bacteria, no potential of primitive cariogenicity. These candidates were expected as new probiotics with potential oral health benefits and no harmful effects.