Pragmatic Return to Effective Dental Infection Control through Triage and Testing (PREDICT): an observational, feasibility study to improve dental office safety.

BACKGROUND: During the COVID-19 pandemic, there was a substantial interruption of care, with patients and workers fearful to return to the dental office. As dental practice creates a highly aerosolized environment, the potential for spread of airborne illness is magnified. As a means to increase safety and mitigate risk, pre-visit testing for SARS-CoV-2 has the potential to minimize disease transmission in dental offices. The Pragmatic Return to Effective Dental Infection Control through Testing (PREDICT) Feasibility Study examined the logistics and impact of two different testing mechanisms (laboratory-based PCR viral testing and point-of-care antigen testing) in dental offices. METHODS: Dental healthcare workers (DHCWs) and patients in four dental offices within the National Dental Practice-based Research Network participated in this prospective study. In addition to electronic surveys, participants in two offices completed POC testing, while participants in two offices used lab-based PCR methods to detect SARS-CoV-2 infection. Analysis was limited to descriptive measures, with median and interquartile ranges reported for Likert scale responses and mean and standard deviation for continuous variables. RESULTS: Of the total 72 enrolled, 28 DHCWs and 41 patients completed the protocol. Two patients (4.9%) tested positive prior to their visit, while 2 DHCWs (12.5%) tested positive for SARS-CoV-2 infection at the start of the study. DHCWs and patients shared similar degree of concern (69% and 63%, respectively) for contracting COVID-19 from patients, while patients feared contracting COVID-19 from DHCWs less (49%). Descriptive statistics calculations revealed that saliva, tongue epithelial cells, and nasal swabs were the most desirable specimen collection method; both testing (LAB and POC) protocols took similar amounts of total time to complete; and DHCWs and patients reported feeling more comfortable when both groups were tested. CONCLUSIONS: While a larger-scale, network study is necessary for generalizability of results, this feasibility study suggests that SARS-CoV-2 testing can be effectively implemented into dental practice workflows and positively impact perception of safety for DHCWs and patients. As new virulent infectious diseases emerge, preparing dental personnel to employ an entire toolbox of risk mitigation strategies, including testing, may have the potential to decrease dental practice closure time, maintaining continuity of dental care services for patients. TRIAL REGISTRATION: ClinicalTrials.gov: NCT05123742.

Deciphering genomic signatures associating human dental oral craniofacial diseases with cardiovascular diseases using machine learning approaches.

OBJECTIVES: Periodontal diseases are chronic, inflammatory disorders that involve the destruction of supporting tissues surrounding the teeth which leads to permanent damage and substantially heightens systemic exposure. If left untreated, dental, oral, and craniofacial diseases (DOCs), especially periodontitis, can increase an individual's risk in developing complex traits including cardiovascular diseases (CVDs). In this study, we are focused on systematically investigating causality between periodontitis with CVDs with the application of artificial intelligence (AI), machine learning (ML) algorithms, and state-of-the-art bioinformatics approaches using RNA-seq-driven gene expression data of CVD patients. MATERIALS AND METHODS: In this study, we built a cohort of CVD patients, collected their blood samples, and performed RNA-seq and gene expression analysis to generate transcriptomic profiles. We proposed a nexus of AI/ML approaches for the identification of significant biomarkers, and predictive analysis. We implemented recursive feature elimination, Pearson correlation, chi-square, and analysis of variance to detect significant biomarkers, and utilized random forest and support vector machines for predictive analysis. RESULTS: Our AI/ML analyses have led us to the preliminary conclusion that GAS5, GPX1, HLA-B, and SNHG6 are the potential gene markers that can be used to explain the causal relationship between periodontitis and CVDs. CONCLUSIONS: CVDs are relatively common in patients with periodontal disease, and an increased risk of CVD is associated with periodontal disease independent of gender. Genetic susceptibility contributing to periodontitis and CVDs have been suggested to some extent, based on the similar degree of heritability shared between both complex diseases.

Oral microbial interactions from an ecological perspective: a narrative review.

Landscape ecology is a relatively new field of study within the sub-specialty of ecology that considers time and space in addition to structure and function. Landscape ecology contends that both the configuration (spatial pattern) and the composition (organisms both at the macro and or micro level) of an ecology can change over time. The oral cavity is an ideal place to study landscape ecology because of the variety of landscapes, the dynamic nature of plaque biofilm development, and the easy access to biofilm material. This review is intended to provide some specific clinical examples of how landscape ecology can influence the understanding of oral diseases and act as a supplement to diagnosis and treatment. The purpose of this review is two-fold; (1) to illustrate how landscape ecology can be used to clarify the two most prominent microbiologically induced infections in the oral cavity, and (2) how studies of oral microbiology can be used to enhance the understanding of landscape ecology. The review will distinguish between "habitat" and "niche" in a landscape and extend the concept that a "patch", is the demarcating unit of a habitat within a landscape. The review will describe how; (1) an individual patch, defined by its shape, edges and internal components can have an influence on species within the patch, (2) spatial dynamics over time within a patch can lead to variations or diversities of species within that patch space, and (3) an unwelcoming environment can promote species extinction or departure/dispersion into a more favorable habitat. Understanding this dynamic in relationship to caries and periodontal disease is the focus of this review.

Pragmatic Return to Effective Dental Infection Control through Triage and Testing (PREDICT): A feasibility study to improve dental office safety.

Background: The COVID-19 pandemic highlights the need for practitioners to enhance workflows to increase safety and mitigate risk. As dental practice creates a highly aerosolized environment, pre-visit testing for SARS-CoV-2 has the potential to be an effective mitigation strategy to minimize disease transmission in dental offices. The Pragmatic Return to Effective Dental Infection Control through Testing (PREDICT) Feasibility Study examined the potential, logistics, and impact related to laboratory-based PCR viral testing and point-of-care (POC) antigen testing. Methods: Dental healthcare workers (DHCWs) and patients in four dental offices within the National Dental Practice-based Research Network participated in this prospective study. In addition to electronic surveys, participants in two offices completed POC testing, while participants in two offices used lab based PCR methods to detect SARS-CoV-2 infection. For this feasibility study, analysis was limited to descriptive measures. Median and interquartile ranges were reported for Likert scale responses and mean and standard deviation for continuous variables. Results: Forty-one of forty-three consented patients and twenty-eight of twenty-nine DHCWs completed the protocol. Descriptive statistics calculations including median and interquartile ranges revealed (1) saliva, tongue epithelial cells and nasal swabs were the most desirable specimens for testing for groups (2) both LAB and POC protocols took similar amounts of total time to complete the full testing protocol and (3) DHCWs and patients reported feeling more comfortable when both groups were tested. Conclusions: This feasibility study suggests that pre-visit SARS-CoV-2 testing can be effectively implemented into dental practice workflows and positively impact perception of safety for DHCWs and patients, though a larger scale, network study is necessary for generalizability of results. As new virulent infectious diseases continue to emerge, preparing dental personnel to employ an entire toolbox of risk mitigation strategies, including testing, may have the potential to decrease dental practice closure time, maintaining continuity of dental care services for patients. Trial registration: This trial was registered on ClinicalTrials.gov: NCT05123742.

Oral Epithelial Cells Expressing Low or Undetectable Levels of Human Angiotensin-Converting Enzyme 2 Are Susceptible to SARS-CoV-2 Virus Infection In Vitro.

The oral cavity is thought to be one of the portals for SARS-CoV-2 entry, although there is limited evidence of active oral infection by SARS-CoV-2 viruses. We assessed the capacity of SARS-CoV-2 to infect and replicate in oral epithelial cells. Oral gingival epithelial cells (hTERT TIGKs), salivary gland epithelial cells (A-253), and oral buccal epithelial cells (TR146), which occupy different regions of the oral cavity, were challenged with replication-competent SARS-CoV-2 viruses and with pseudo-typed viruses expressing SARS-CoV-2 spike proteins. All oral epithelial cells expressing undetectable or low levels of human angiotensin-converting enzyme 2 (hACE2) but high levels of the alternative receptor CD147 were susceptible to SARS-CoV-2 infection. Distinct viral dynamics were seen in hTERT TIGKs compared to A-253 and TR146 cells. For example, levels of viral transcripts were sustained in hTERT TIGKs but were significantly decreased in A-253 and TR146 cells on day 3 after infection. Analysis of oral epithelial cells infected by replication-competent SARS-CoV-2 viruses expressing GFP showed that the GFP signal and SARS-CoV-2 mRNAs were not evenly distributed. Furthermore, we found cumulative SARS-CoV-2 RNAs from released viruses in the media from oral epithelial cells on day 1 and day 2 after infection, indicating productive viral infection. Taken together, our results demonstrated that oral epithelial cells were susceptible to SARS-CoV-2 viruses despite low or undetectable levels of hACE2, suggesting that alternative receptors contribute to SARS-CoV-2 infection and may be considered for the development of future vaccines and therapeutics.

The Pragmatic Return to Effective Dental Infection Control Through Triage and Testing (PREDICT) Study: Protocol for a Prospective Clinical Study in the National Dental Practice-Based Research Network.

BACKGROUND: Dental practice has been greatly affected by the COVID-19 pandemic. As SARS-CoV-2 infection is transmitted by respiratory fluids, dental practice techniques, which include aerosol-generating procedures, can increase the risk of transmission causing heightened safety concerns for both dental health care workers (DHCWs) and patients. These concerns have resulted in the reduction in patient volume and the available workforce within dental practices across the United States. Standardized methods for COVID-19 triage and testing may lead to increased safety and perceptions of safety for DHCWs and their patients and promote willingness to provide and access oral health care services. OBJECTIVE: This study is designed to develop procedures that test the feasibility of enhanced COVID-19 triage and testing in dental offices. It will provide preliminary data to support a larger network-wide study grant application aimed at developing protocols to address safety concerns of patients and DHCWs in a peri-COVID-19 pandemic era. METHODS: The feasibility study is being conducted in 4 private dental practices, each of which has a dentist member of the National Dental Practice-Based Research Network. Participants include the DHCWs and patients of the dental practice. Study procedures include completion of COVID-19 triage, completion of COVID-19 testing (point-of-care [POC] or laboratory-based [LAB] SARS-CoV-2 viral, antigen, and antibody tests based on office designation), and administration of perception and attitude surveys for participating DCHWs and patients of the dental practice over a defined study period. The office designation and the participant's role in the practice determines which testing protocol is executed within the office. There are 4 study groups following 4 distinct protocols: (1) POC DHCWs, (2) POC patients, (3) LAB DHCWs, and (4) LAB patients. RESULTS: Data collection began in December of 2021 and concluded in March 2022. Study results are expected to be published in fall 2022. CONCLUSIONS: The results of this feasibility study will help identify the viability and functionality of COVID-19 triage and testing in dental practices and inform a larger network-wide study grant application that develops protocols that address safety concerns of patients and DHCWs in a COVID-19 environment. TRIAL REGISTRATION: ClinicalTrials.gov NTC05123742; https://clinicaltrials.gov/ct2/show/NCT05123742?term=NCT05123742. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/38386.

iPSC-derived cranial neural crest-like cells can replicate dental pulp tissue with the aid of angiogenic hydrogel.

The dental pulp has irreplaceable roles in maintaining healthy teeth and its regeneration is a primary aim of regenerative endodontics. This study aimed to replicate the characteristics of dental pulp tissue by using cranial neural crest (CNC)-like cells (CNCLCs); these cells were generated by modifying several steps of a previously established method for deriving NC-like cells from induced pluripotent stem cells (iPSCs). CNC is the anterior region of the neural crest in vertebrate embryos, which contains the primordium of dental pulp cells or odontoblasts. The produced CNCLCs showed approximately 2.5-12,000-fold upregulations of major CNC marker genes. Furthermore, the CNCLCs exhibited remarkable odontoblastic differentiation ability, especially when treated with a combination of the fibroblast growth factors (FGFs) FGF4 and FGF9. The FGFs induced odontoblast marker genes by 1.7-5.0-fold, as compared to bone morphogenetic protein 4 (BMP4) treatment. In a mouse subcutaneous implant model, the CNCLCs briefly fated with FGF4 + FGF9 replicated dental pulp tissue characteristics, such as harboring odontoblast-like cells, a dentin-like layer, and vast neovascularization, induced by the angiogenic self-assembling peptide hydrogel (SAPH), SLan. SLan acts as a versatile biocompatible scaffold in the canal space. This study demonstrated a successful collaboration between regenerative medicine and SAPH technology.

The Opioid Analgesic Reduction Study (OARS)-a comparison of opioid vs. non-opioid combination analgesics for management of post-surgical pain: a double-blind randomized clinical trial.

BACKGROUND: Everyday people die unnecessarily from opioid overdose-related addiction. Dentists are among the leading prescribers of opioid analgesics. Opioid-seeking behaviors have been linked to receipt of initial opioid prescriptions following the common dental procedure of third molar extraction. With each opioid prescription, a patient's risk for opioid misuse or abuse increases. With an estimated 56 million tablets of 5 mg hydrocodone annually prescribed after third molar extractions in the USA, 3.5 million young adults may be unnecessarily exposed to opioids by dentists who are inadvertently increasing their patient's risk for addiction. METHODS: A double-blind, stratified randomized, multi-center clinical trial has been designed to evaluate whether a combination of over-the-counter non-opioid-containing analgesics is not inferior to the most prescribed opioid analgesic. The impacted 3rd molar extraction model is being used due to the predictable severity of the post-operative pain and generalizability of results. Within each site/clinic and gender type (male/female), patients are randomized to receive either OPIOID (hydrocodone/acetaminophen 5/300 mg) or NON-OPIOID (ibuprofen/acetaminophen 400/500 mg). Outcome data include pain levels, adverse events, overall patient satisfaction, ability to sleep, and ability to perform daily functions. To develop clinical guidelines and a clinical decision-making tool, pain management, extraction difficulty, and the number of tablets taken are being collected, enabling an experimental decision-making tool to be developed. DISCUSSION: The proposed methods address the shortcomings of other analgesic studies. Although prior studies have tested short-term effects of single doses of pain medications, patients and their dentists are interested in managing pain for the entire post-operative period, not just the first 12 h. After surgery, patients expect to be able to perform normal daily functions without feeling nauseous or dizzy and they desire a restful sleep at night. Parents of young people are concerned with the risks of opioid use and misuse, related either to treatments received or to subsequent use of leftover pills. Upon successful completion of this clinical trial, dentists, patients, and their families will be better able to make informed decisions regarding post-operative pain management. TRIAL REGISTRATION: ClinicalTrials.gov NCT04452344 . Registered on June 20, 2020.

Altered Prevalence of Pulp Diagnoses in Diabetes Mellitus Patients: A Retrospective Study.

INTRODUCTION: Diabetes mellitus (DM) is a complex multisystemic disorder that affects an estimated 21 million Americans. No studies have evaluated the association of DM with the prevalence of each pulpal diagnosis. The objective of this study was to compare the prevalence of each pulp diagnosis including symptomatic irreversible pulpitis (SIP), asymptomatic irreversible pulpitis, reversible pulpitis, normal pulp, and pulp necrosis (PN) in DM patients against a nondiabetic control group. METHODS: A retrospective chart review was approved by Rutgers University Institutional Review Board. The prevalence of the diagnoses SIP, asymptomatic irreversible pulpitis, reversible pulpitis, normal pulp, and PN was calculated from AxiUm (Exan software, Las Vegas, NV) electronic health records at Rutgers School of Dental Medicine. The chi-square test was used to see the relationship between the 2 categoric variables. Second, binary logistic regression analyses were performed for each group. RESULTS: A total of 2979 teeth were diagnosed with a pulp condition between April 2013 and November 2018. The total tooth number of DM patients was 682, whereas the tooth number of nondiabetic patients was 2297. In the subgroup of patients younger than 40 years old, SIP was notably more prevalent in DM patients. In addition, the prevalence of PN in elderly DM patients (60-69 years old) was significantly higher than in the control group. CONCLUSIONS: The prevalence of SIP in DM patients was significantly higher compared with the control group (<40 years old), suggesting the possibility that DM could hypersensitize the subgroup of patients younger than 40 years old to pulpitis pain.

Determinants and Dynamics of SARS-CoV-2 Infection in a Diverse Population: 6-Month Evaluation of a Prospective Cohort Study.

BACKGROUND: We studied risk factors, antibodies, and symptoms of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in a diverse, ambulatory population. METHODS: A prospective cohort (n = 831) previously undiagnosed with SARS-CoV-2 infection underwent serial testing (SARS-CoV-2 polymerase chain reaction, immunoglobulin G [IgG]) for 6 months. RESULTS: Ninety-three participants (11.2%) tested SARS-CoV-2-positive: 14 (15.1%) asymptomatic, 24 (25.8%) severely symptomatic. Healthcare workers (n = 548) were more likely to become infected (14.2% vs 5.3%; adjusted odds ratio, 2.1; 95% confidence interval, 1.4-3.3) and severely symptomatic (29.5% vs 6.7%). IgG antibodies were detected after 79% of asymptomatic infections, 89% with mild-moderate symptoms, and 96% with severe symptoms. IgG trajectories after asymptomatic infections (slow increases) differed from symptomatic infections (early peaks within 2 months). Most participants (92%) had persistent IgG responses (median 171 days). In multivariable models, IgG titers were positively associated with symptom severity, certain comorbidities, and hospital work. Dyspnea and neurologic changes (including altered smell/taste) lasted ≥ 120 days in ≥ 10% of affected participants. Prolonged symptoms (frequently more severe) corresponded to higher antibody levels. CONCLUSIONS: In a prospective, ethnically diverse cohort, symptom severity correlated with the magnitude and trajectory of IgG production. Symptoms frequently persisted for many months after infection.Clinical Trials Registration. NCT04336215.

Ezh2 knockout in mesenchymal cells causes enamel hyper-mineralization.

Enhancer of zeste homolog 2 (EZH2) is the catalytic core of polycomb repressive complex 2 (PRC2), which primarily methylates lysine 27 on histone H3 (H2K27me3), generating transcriptionally suppressed heterochromatin. Since EZH2 suppresses expression of genes involved in dentin formation, we examined the role of EZH2 in tooth development. Intriguingly, microCT analysis of teeth from mice with conditional Ezh2 knockout in uncommitted mesenchymal cells showed hyper-mineralization of enamel, which is produced by the epithelial-lineage cells, ameloblasts. Scanning electron microscopy analysis and nano-indentation of the incisor enamel from knockout mice revealed smaller inter-rod spaces and higher hardness compared to wild type enamel, respectively. Interestingly, expression of the calcium channel subunit gene, Orai2, was decreased compared to its competitor, Orai1, both in knockout mouse incisors and the ex vivo culture of ameloblasts with the surrounding tissues under EZH2 inhibition. Moreover, histological analysis of incisor from knockout mice showed decreased ameloblastin and expedited KLK4 expression in the ameloblasts. These observations suggest that EZH2 depletion in dental mesenchymal cells reduces enamel matrix formation and increases enamel protease activity from ameloblasts, resulting in enamel hyper-mineralization. This study demonstrates the significant role of the suppressive H3K27me3 mark for heterochromatin on enamel formation.

COVID-19 and Dentistry: Biological Considerations, Testing Strategies, Issues, and Regulations.

The COVID-19 pandemic has created a new and demanding work environment for health professionals. This article will focus on the biological issues related to infection and disease, tests developed based on these biological principles, the ways in which these tests are evaluated, and how they can be used to protect both patients, dental professionals, and office affiliates. The article will describe types of COVID-19 testing that may be performed in dental offices, the issue of testing and anxiety, regulations regarding testing that are relevant to dentists, rules for delivery and reimbursement, and strategies for proceeding as a health professional in the current challenging environment. The authors conclude that the devastating effects of the pandemic on public health has facilitated a new role for dentists as public health professionals, with the opportunity for the dental profession to actively expand its participation in improving the health of the public moving forward. Testing will continue as a means of relieving anxiety for the public.

Differential Effects of Antiseptic Mouth Rinses on SARS-CoV-2 Infectivity In Vitro.

Severe acute respiratory syndrome-related coronavirus (SARS-CoV-2) is detectable in saliva from asymptomatic individuals, suggesting a potential benefit from the use of mouth rinses to suppress viral load and reduce virus spread. Published studies on the reduction of SARS-CoV-2-induced cytotoxic effects by mouth rinses do not exclude antiseptic mouth rinse-associated cytotoxicity. Here, we determined the effect of commercially available mouth rinses and antiseptic povidone-iodine on the infectivity of replication-competent SARS-CoV-2 viruses and of pseudotyped SARS-CoV-2 viruses. We first determined the effect of mouth rinses on cell viability to ensure that antiviral activity was not a consequence of mouth rinse-induced cytotoxicity. Colgate Peroxyl (hydrogen peroxide) exhibited the most cytotoxicity, followed by povidone-iodine, chlorhexidine gluconate (CHG), and Listerine (essential oils and alcohol). The potent antiviral activities of Colgate Peroxyl mouth rinse and povidone-iodine were the consequence of rinse-mediated cellular damage when the products were present during infection. The potency of CHG was greater when the product was not washed off after virus attachment, suggesting that the prolonged effect of mouth rinses on cells impacts the antiviral outcome. To minimalize mouth rinse-associated cytotoxicity, mouth rinse was largely removed from treated viruses by centrifugation prior to infection of cells. A 5% (v/v) dilution of Colgate Peroxyl or povidone-iodine completely blocked viral infectivity. A similar 5% (v/v) dilution of Listerine or CHG had a moderate suppressive effect on the virus, but a 50% (v/v) dilution of Listerine or CHG blocked viral infectivity completely. Mouth rinses inactivated the virus without prolonged incubation. The new infectivity assay, with limited impacts of mouth rinse-associated cytotoxicity, showed the differential effects of mouth rinses on SARS-CoV-2 infection. Our results indicate that mouth rinses can significantly reduce virus infectivity, suggesting a potential benefit for reducing SARS-CoV-2 spread.

Dysbiosis From a Microbial and Host Perspective Relative to Oral Health and Disease.

The significance of microbiology and immunology with regard to caries and periodontal disease gained substantial clinical or research consideration in the mid 1960's. This enhanced emphasis related to several simple but elegant experiments illustrating the relevance of bacteria to oral infections. Since that point, the understanding of oral diseases has become increasingly sophisticated and many of the original hypotheses related to disease causality have either been abandoned or amplified. The COVID pandemic has reminded us of the importance of history relative to infectious diseases and in the words of Churchill "those who fail to learn from history are condemned to repeat it." This review is designed to present an overview of broad general directions of research over the last 60 years in oral microbiology and immunology, reviewing significant contributions, indicating emerging foci of interest, and proposing future directions based on technical advances and new understandings. Our goal is to review this rich history (standard microbiology and immunology) and point to potential directions in the future (omics) that can lead to a better understanding of disease. Over the years, research scientists have moved from a position of downplaying the role of bacteria in oral disease to one implicating bacteria as true pathogens that cause disease. More recently it has been proposed that bacteria form the ecological first line of defense against "foreign" invaders and also serve to train the immune system as an acquired host defensive stimulus. While early immunological research was focused on immunological exposure as a modulator of disease, the "hygiene hypothesis," and now the "old friends hypothesis" suggest that the immune response could be trained by bacteria for long-term health. Advanced "omics" technologies are currently being used to address changes that occur in the host and the microbiome in oral disease. The "omics" methodologies have shaped the detection of quantifiable biomarkers to define human physiology and pathologies. In summary, this review will emphasize the role that commensals and pathobionts play in their interaction with the immune status of the host, with a prediction that current "omic" technologies will allow researchers to better understand disease in the future.

Adaptation by Ancient Horizontal Acquisition of Butyrate Metabolism Genes in Aggregatibacter actinomycetemcomitans.

Like the bacterial residents of the human gut, it is likely that many of the species in the human oral microbiota have evolved to better occupy and persist in their niche. Aggregatibacter actinomycetemcomitans (Aa) is both a common colonizer of the oral cavity and has been implicated in the pathogenesis of periodontal disease. Here, we present a whole-genome phylogenetic analysis of Aa isolates from humans and nonhuman primates that revealed an ancient origin for this species and a long history of association with the Catarrhini, the lineage that includes Old World monkeys (OWM) and humans. Further genomic analysis showed a strong association with the presence of a short-chain fatty acid (SCFA) catabolism locus (atoRDAEB) in many human isolates that was absent in almost all nonhuman OWM isolates. We show that this locus was likely acquired through horizontal gene transfer. When grown under conditions that are similar to those at the subgingival site of periodontitis (anaerobic, SCFA replete), Aa strains with atoRDAEB formed robust biofilms and showed upregulation of genes involved in virulence, colonization, and immune evasion. Both an isogenic deletion mutant and nonhuman primate isolates lacking the ato locus failed to grow in a robust biofilm under these conditions, but grew well under the carbohydrate-rich conditions similar to those found above the gumline. We propose that the acquisition of the ato locus was a key evolutionary step allowing Aa to utilize SCFAs, adapt, and modulate subgingival disease.IMPORTANCE There has been considerable interest in the impact of short-chain fatty acids (SCFAs) on inflammatory effects related to the microbiome. Here, we present evidence that SCFAs may also be important in disease by providing an energy source or disease-associated cue for colonizing pathogens. We propose that SCFAs allow Aggregatibacter actinomycetemcomitans (Aa) to adapt to the subgingival anaerobic environment, which is the site of human periodontitis. Under anaerobic, SCFA-rich conditions, human-derived Aa strains that possess butyrate metabolism genes form strong biofilms and upregulate virulence genes. Our phylogenetic analysis highlights a long history of evolution of Aa with its primate hosts and suggests that the acquisition of butyrate metabolism genes may have been a critical step in allowing Aa to colonize a new niche and cause disease in humans. Overall, this study highlights the important role that horizontal gene transfer may play in microbial adaptation and the evolution of infectious disease.

Differential effects of antiseptic mouth rinses on SARS-CoV-2 infectivity in vitro.

SARS-CoV-2 is detectable in saliva from asymptomatic individuals, suggesting a potential benefit from the use of mouth rinses to suppress viral load and reduce virus spread. Published studies on reduction of SARS-CoV-2-induced cytotoxic effects by antiseptics do not exclude antiseptic-associated cytotoxicity. Here, we determined the effect of commercially available mouth rinses and antiseptic povidone-iodine on the infectivity of SARS-CoV-2 virus and of a non-pathogenic, recombinant, SARS-CoV-2 infection vector (pseudotyped SARS-CoV-2 virus). We first determined the effect of mouth rinses on cell viability to ensure that antiviral activity was not a consequence of mouth rinse-induced cytotoxicity. Colgate Peroxyl (hydrogen peroxide) exhibited the most cytotoxicity, followed by povidone-iodine, chlorhexidine gluconate (CHG), and Listerine (essential oils and alcohol). Potent anti-viral activities of povidone iodine and Colgate peroxyl mouth rinses was the consequence of rinse-mediated cellular damage. The potency of CHG was greater when the product was not washed off after virus attachment, suggesting that the prolonged effect of mouth rinses on cells impacts anti-viral activity. To minimalize mouth rinse-associated cytotoxicity, mouth rinse was largely removed from treated-viruses by centrifugation prior to infection of cells. A 5% (v/v) dilution of Colgate Peroxyl or povidone-iodine completely blocked viral infectivity. A similar 5% (v/v) dilution of Listerine or CHG had a moderate suppressive effect on the virus, but a 50% (v/v) dilution of Listerine or CHG blocked viral infectivity completely. Prolonged incubation of virus with mouth rinses was not required for viral inactivation. Our results indicate that mouth rinses can significantly reduce virus infectivity, suggesting a potential benefit for reducing SARS-CoV-2 spread.

Aggregatibacter, A Low Abundance Pathobiont That Influences Biogeography, Microbial Dysbiosis, and Host Defense Capabilities in Periodontitis: The History of A Bug, And Localization of Disease.

Aggregatibacter actinomycetemcomitans, the focus of this review, was initially proposed as a microbe directly related to a phenotypically distinct form of periodontitis called localized juvenile periodontitis. At the time, it seemed as if specific microbes were implicated as the cause of distinct forms of disease. Over the years, much has changed. The sense that specific microbes relate to distinct forms of disease has been challenged, as has the sense that distinct forms of periodontitis exist. This review consists of two components. The first part is presented as a detective story where we attempt to determine what role, if any, Aggregatibacter plays as a participant in disease. The second part describes landscape ecology in the context of how the host environment shapes the framework of local microbial dysbiosis. We then conjecture as to how the local host response may limit the damage caused by pathobionts. We propose that the host may overcome the constant barrage of a dysbiotic microbiota by confining it to a local tooth site. We conclude speculating that the host response can confine local damage by restricting bacteremic translocation of members of the oral microbiota to distant organs thus constraining morbidity and mortality of the host.