Oral bacteria in infective endocarditis requiring surgery: a retrospective analysis of 134 patients

Streptococcus gordonii Supragingival Bacterium Oral Infection-Induced Periodontitis and Robust miRNA Expression Kinetics

Streptococcus gordonii (S. gordonii, Sg) is one of the early colonizing, supragingival commensal bacterium normally associated with oral health in human dental plaque. MicroRNAs (miRNAs) play an important role in the inflammation-mediated pathways and are involved in periodontal disease (PD) pathogenesis. PD is a polymicrobial dysbiotic immune-inflammatory disease initiated by microbes in the gingival sulcus/pockets. The objective of this study is to determine the global miRNA expression kinetics in S. gordonii DL1-infected C57BL/6J mice. All mice were randomly divided into four groups (n = 10 mice/group; 5 males and 5 females). Bacterial infection was performed in mice at 8 weeks and 16 weeks, mice were euthanized, and tissues harvested for analysis. We analyzed differentially expressed (DE) miRNAs in the mandibles of S. gordonii-infected mice. Gingival colonization/infection by S. gordonii and alveolar bone resorption (ABR) was confirmed. All the S. gordonii-infected mice at two specific time points showed bacterial colonization (100%) in the gingival surface, and a significant increase in mandible and maxilla ABR (p < 0.0001). miRNA profiling revealed 191 upregulated miRNAs (miR-375, miR-34b-5p) and 22 downregulated miRNAs (miR-133, miR-1224) in the mandibles of S. gordonii-infected mice at the 8-week mark. Conversely, at 16 weeks post-infection, 10 miRNAs (miR-1902, miR-203) were upregulated and 32 miRNAs (miR-1937c, miR-720) were downregulated. Two miRNAs, miR-210 and miR-423-5p, were commonly upregulated, and miR-2135 and miR-145 were commonly downregulated in both 8- and 16-week-infected mice mandibles. Furthermore, we employed five machine learning (ML) algorithms to assess how the number of miRNA copies correlates with S. gordonii infections in mice. In the ML analyses, miR-22 and miR-30c (8-week), miR-720 and miR-339-5p (16-week), and miR-720, miR-22, and miR-339-5p (combined 8- and 16-week) emerged as the most influential miRNAs.

[Teeth and oral cavity at the heart of systemic health]

Research into the interrelationships between oral and systemic diseases has been growing exponentially for over 20 years. Teeth and their supporting tissues can be affected by pathologies, particularly infectious ones, the consequences of which are felt locally in the oral cavity and at a distance in the body. Oral diseases frequently lead to the maintenance of an inflammatory state in oral bones and mucosa, which complicates the treatment of systemic inflammatory pathologies. The aim of this review is to take stock of current knowledge concerning the interrelationships that may exist between the oral environment and other organs, in both adults and children.

'A series of unfortunate events': a case report of infective endocarditis resulting from ventricular arrhythmia ablation

Background

Radiofrequency ablation (RFA) is the most effective non-pharmacological approach in the reduction of ventricular tachycardia (VT) recurrence. However, it is crucial to thoroughly screen every patient for contraindications for RFA and provide appropriate pharmacological prophylaxis, if needed, since adverse effects may be fatal.

Case summary

A 77-year-old male with multi-vessel coronary artery disease, heart failure with reduced ejection fraction (New York Heart Association (NYHA) Class III), with implantable cardioverter-defibrillator was admitted to our clinic due to recurrent life-threatening VT. The patient presented several concomitant diseases: dyslipidaemia, hypertension, and chronic kidney disease in Stage IIIB. He had a history of two myocardial infarctions and coronary artery bypass grafts complicated by mediastinitis and dehiscence of a sternotomy scar (2013). Radiofrequency ablation and pace mapping of VT were performed in sterile conditions, but no pre-operative antibiotic prophylaxis was administered. There were no local or general complications in the post-operative period. The patient was discharged from the clinic in good condition. A week later, the patient suffered from septic shock and infective endocarditis of mitral valve complicated with infiltration of the ventricular septum, wall dissection of the left ventricle (LV), pseudoaneurysm, and abscess of the LV. At the time of the second hospitalization extensive dental carries were found and oral cavity sanitation was performed. Due to the severity of the condition, patient did not survive.

Conclusion

Oral cavity infections are common but often overlooked, mainly when the RFA procedure is urgent. A thorough physical examination, including a dental check-up, is crucial to minimize the risk of potential infection of the endocardial tissue and maximize the benefits of the therapy. Still, it is possible that the myocardial infection was not a result of oral cavity infection but a result of other undiagnosed and untreated infection. Contamination of the procedure site with patients' own microbiota or foreign microorganisms by the medical personnel is also a likely and unfortunate scenario. The presented case highlights the significance of not only prophylaxis, screening, and treatment of possible inflammation sites before RFA but also the need for sustaining sanitary standards and sterile conditions.

Bibliometric research on analysis of links between periodontitis and cardiovascular diseases

Background

Periodontitis (PD) and cardiovascular diseases (CVD) rank among the most prevalent pathologies worldwide, and their correlation has been a subject of prolonged investigation. Numerous studies suggest shared etiological factors; however, a definitive causal connection remains unestablished. The objective of this study was to employ bibliometric and visual analyses in order to comprehensively examine the overarching characteristics, focal areas of research, and prospective trends pertaining to the PD-CVD relationship.

Methods

We sourced articles, reviews, and online publications on PD- and CVD- research from the Web of Science Core Collection (WoSCC) spanning from January 1, 1993, to May 15, 2023. A triad of analytical tools (R-Bibliometrix, VOSviewer 1.6.19, and CiteSpace 6.2.R3) were utilized to facilitate collaboration network analysis, co-citation analysis, co-occurrence analysis, and citation burst detection.

Results

Out of the 1,116 publications that fulfilled the eligibility criteria in the WoSCC database, the comprehensive characteristics analysis divulged a sustained growth trend in publication frequency. In the cluster analysis of reference co-citation and keyword co-occurrence, prominent themes such as "periodontitis", "cardiovascular diseases", "inflammation", "Porphyromonas gingivalis", and "atherosclerosis" consistently emerged. Contemporary topics such as "peri-implantitis," "COVID-19", "cardiovascular risk factors," and "endocarditis" were pinpointed as burgeoning research hotspots.

Conclusion

Based on this bibliometric study, in the field of association studies between PD and CVD, the etiologic mechanisms of both diseases have been intensively studied in the last three decades. Periodontal pathogens might serve as potential initiating factors linking PD and CVD. Inflammation may constitute a significant etiological factor shared by both diseases. Several emerging topics, such as COVID-19 and peri-implantitis, exhibit promising potential. This exhaustive overview casts light on pivotal research arenas, augmenting the field's understanding and stimulating further scholarly investigations.

Regulatory effects of oral microbe on intestinal microbiota and the illness

Over the past decade, the association between oral health, intestinal microbiota, and systemic diseases has been further validated. Some oral microbial species have been isolated from pathological intestine mucosa or feces and identified as biomarkers for intestinal diseases. A small proportion of oral microbiome passes through or colonizes the lower gastrointestinal tract, even in healthy individuals. Opportunistic pathogens from the oral cavity may expand and participate in the occurrence and progression of intestinal diseases when the anatomical barrier is disrupted. These disruptors interact with the intestinal microbiota, disturbing indigenous microorganisms, and mucosal barriers through direct colonization, blood circulation, or derived metabolite pathways. While interacting with the host's immune system, oral-derived pathogens stimulate inflammation responses and guide the transition of the intestinal microenvironment from a healthy state to a pre-disease state. Therefore, the oral-gut microbiome axis sheds light on new clinical therapy options, and gastrointestinal tract ecology balance necessitates simultaneous consideration of both oral and gut microbiomes. This review summarizes possible routes of oral microbes entering the intestine and the effects of certain oral bacteria on intestinal microbiota and the host's immune responses.

Oral microbes and the formation of cerebral abscesses: A single-centre retrospective study

OBJECTIVE

Intracranial abscesses are relatively uncommon, but can result in significant mortality and morbidity. Whilst many potential causes of brain abscesses are recognised, in many cases the origin of infection remains clinically unidentified. Our objective was to investigate the role of bacteria found in the oral cavity in the development of brain abscesses.

METHODS

A retrospective analysis was performed using data from 87 patients admitted to a single UK neurosurgical unit with brain abscesses over a 16-year period. Using microbiological data obtained from abscess sampling and peripheral cultures, species of bacteria were categorised in patients where no primary source of infection was identified (NSI) for their brain abscess (n = 52), or where an infective source (ISI) was identified. The microbiological data was then screened to identify common oral bacteria in each group.

RESULTS

Brain abscesses from the ISI group (n = 35) demonstrated a significantly lower preponderance of oral bacteria (n = 8), than the NSI group (n = 29) (p < 0.05). Brain abscesses from the NSI group also had significantly higher counts of Streptococcus anginosus compared to ISI (p < 0.05), with brain abscesses being most common in the frontal and parietal lobes for both ISI and NSI.

CONCLUSIONS

These findings suggest that the oral cavity could be considered as a source of occult infection in cases of brain abscess where no clear cause has been identified. Future studies should include oral screening and microbiome analysis to better understand the mechanisms involved and develop approaches for prevention.

CLINICAL SIGNIFICANCE STATEMENT

Oral bacteria may be an under-recognised cause of brain abscesses. Careful review of oral health in brain abscess patients may help establish causation, particularly in patients with no cause for their abscess identified. Good levels of oral health may help prevent the development of brain abscesses in some individuals.

Antimicrobial Peptides Active in In Vitro Models of Endodontic Bacterial Infections Modulate Inflammation in Human Cardiac Fibroblasts

Endodontic and periodontal disease are conditions of infectious origin that can lead to tooth loss or develop into systemic hyperinflammation, which may be associated with a wide variety of diseases, including cardiovascular. Endodontic and periodontal treatment often relies on antibiotics. Since new antimicrobial resistances are a major threat, the use of standard antibiotics is not recommended when the infection is only local. Antimicrobial peptides were recently demonstrated to be valid alternatives for dental treatments. The antimicrobial peptide M33D is a tetrabranched peptide active against Gram-negative and Gram-positive bacteria. It has a long life, unusual for peptides, because its branched form provides resistance to proteases. Here the efficacy of M33D and of its analog M33i/l as antibiotics for local use in dentistry was evaluated. M33D and M33i/l were active against reference strains and multidrug-resistant clinical isolates of Gram-negative and Gram-positive species. Their minimum inhibitory concentration against different strains of dental interest was between 0.4 and 6.0 μM. Both peptides acted rapidly on bacteria, impairing membrane function. They also disrupted biofilm effectively. Disinfection of the root canal is crucial for endodontic treatments. M33D and M33i/l reduced E. faecalis colonies to one-twentieth in a dentin slices model reproducing root canal irrigation. They both captured and neutralized lipopolysaccharide (LPS), a bacterial toxin responsible for inflammation. The release of IL-1β and TNFα by LPS-stimulated murine macrophages was reduced by both peptides. Human cardiac fibroblasts respond to different insults with the release of proinflammatory cytokines, and consequently, they are considered directly involved in atherogenic cardiovascular processes, including those triggered by infections. The presence of M33D and M33i/l at MIC concentration reduced IL6 release from LPS- stimulated human cardiac fibroblasts, hence proving to be promising in preventing bacteria-induced atherogenesis. The two peptides showed low toxicity to mammalian cells, with an EC50 one order of magnitude higher than the average MIC and low hemolytic activity. The development of antimicrobial peptides for dental irrigations and medication is a very promising new field of research that will provide tools to fight dental infections and their severe consequences, while at the same time protecting standard antibiotics from new outbreaks of antimicrobial resistance.