Oral Organisms Research Articles

Do we need to improve the general oral health of our population to reduce the risk of Infective Endocarditis?

Abstract Background Emphasis is placed on the link between oral health and Infective Endocarditis (IE), particularly around odontogenic infections and specific dental procedures. The Adult Dental Health Survey in 2009 showed 45% of adults in the UK required dental intervention typically associated with developing IE. Antibiotic prophylaxis in this context is not without controversy. With gum and periodontic disease endemic, is the modern issue one of generalised poor oral health as a risk factor for IE? Purpose To determine the impact of oral health on risk and outcome in IE. Terminology SDCEP published dental guidelines of when to consider AP against IE for dental procedures. It identifies dental procedures that can cause transient bacteraemia. Methodology Data were collected from October 2020-Januaury 2023 in 123 patients with confirmed IE at a central London cardiac surgical centre. Patients had a focussed dental assessment with history, intraoral examination and dental panoramic radiograph to determine the risk and extent of oral disease. Results Average age was 54.2years. 77/123 (63%) had native IE (NVE) and 46 (37%) prosthetic (PVE). 17 (37%) cultured oral organisms from blood (Table 1); 8 (47%) of these organisms are associated with active dental disease (decay, periodontal disease, dental infection). Organisms can be found in Table 2. However, 93/123 (76%) had oral caries requiring dental treatment, irrespective of typical portal of entry for that organism. The proposed dental treatment posed a high risk for causing IE in 70%. 93/123 (76%) needed further dental treatment within six months rendering only 12% of patients orally stable. Oral organisms were seen more frequently in NVE (41/77) vs PVE (17/46). There was no difference in the incidence of dental disease requiring treatment (77% NVE vs 74% PVE). Whilst 27% of PVE had had recent (within 4 months) dental treatment compared to 73% NVE, only 1 PVE patient grew an oral commensal compared to 82% of NVE patients. Conclusion Prevention of IE is key to reducing the morbidity and mortality of this disease. We see oral commensals causing IE in 47%, with only 12% of this modern IE cohort dentally stable. Despite this, there was no difference in rates of dental disease requiring invasive treatment when stratified by oral vs non-oral organisms. A robust public health strategy is required to reduce the risk of oral disease driving IE.

COMPARISON OF THE INHIBITORY EFFECT BETWEEN ULIN (Eusideroxylon zwageri) BARK EXTRACT AND Chlorhexidine gluconate 0.2% AGAINST Streptococcus sanguinis

Background: Gingivitis is caused by a build up of plaque bacteria, one of which is Streptococcus sanguinis. Streptococcus sanguinis act as an anchor for the attachment of oral organisms that colonize the surface of the teeth, forming plaque so that it becomes the development of gingivitis. Currently, many natural ingredients, as alternatives, have antibacterial effects. One of which is Eusideroxylon zwageri, because it contains flavonoids, tannins, phenolics, saponins, alkaloids, and terpenoids. Purpose: to compare the inhibitory effect between ulin bark extract and Chlorhexidine gluconate 0.2% against Streptococcus sanguinis. Method: True experimental research with post test only with control group design using ulin bark extract concentrations of 20%, 40%, 60%, 80%, and 100% and Chlorhexidine gluconate 0.2% as the K(+). The maceration method was used to extract ulin bark while the inhibitory test was using the diffusion method with 6 treatment groups and 4 replications, so that there were 24 samples. All treatment groups were incubated 24 hours at 37oC then measurement of inhibition zones was using callipers. Results: The results of the test showed that ulin bark extract concentrations of 20%, 40%, 60%, 80%, 100%, and Chlorhexidine gluconate 0.2% obtained an average inhibition zone with diameter of 7.18 mm, 9.06 mm, 11.08 mm, 13 mm, 15.09 mm, and 18.14 mm. Analysis of One Way ANOVA and Post Hoc Games-Howell data showed a significant difference between treatment groups. Conclusion: Ulin bark extract can inhibit the growth of Streptococcus sanguinis but has not been able to equal to Chlorhexidine gluconate 0.2%. Keywords: Chlorhexidine gluconate 0,2%, gingivitis, inhibitory activity, ulin bark extract, Streptococcus sanguinis.

Tannerella forsythia scavenges Fusobacterium nucleatum secreted NOD2 stimulatory molecules to dampen oral epithelial cell inflammatory response.

The oral organism Tannerella forsythia is auxotrophic for peptidoglycan amino sugar N-acetylmuramic acid (MurNAc). It survives in the oral cavity by scavenging MurNAc- and MurNAc-linked peptidoglycan fragments (muropeptides) secreted by co-habiting bacteria such as Fusobacterium nucleatum with which it forms synergistic biofilms. Muropeptides, MurNAc-l-Ala-d-isoGln (MDP, muramyl dipeptide) and d-γ-glutamyl-meso-DAP (iE-DAP dipeptide), are strong immunostimulatory molecules that activate nucleotide oligomerization domain (NOD)-like innate immune receptors and induce the expression of inflammatory cytokines and antimicrobial peptides. In this study, we utilized an in vitro T. forsythia-F. nucleatum co-culture model to determine if T. forsythia can selectively scavenge NOD ligands from the environment and impact NOD-mediated inflammation. The results showed that NOD-stimulatory molecules were secreted by F. nucleatum in the spent culture broth, which subsequently induced cytokine and antimicrobial peptide expression in oral epithelial cells. In the spent broth from T. forsythia-F. nucleatum co-cultures, the NOD-stimulatory activity was significantly reduced. These data indicated that F. nucleatum releases NOD2-stimulatory muropeptides in the environment, and T. forsythia can effectively scavenge the muropeptides released by co-habiting bacteria to dampen NOD-mediated host responses. This proof-of-principle study demonstrated that peptidoglycan scavenging by T. forsythia can impact the innate immunity of oral epithelium by dampening NOD activation.

Interleukin 1 beta and its association with the periodontal health of pregnant women

ObjectivesIn this study, we measured and compared serum and gingival crevicular fluid (GCF) levels of interleukin 1 beta (IL-1β) in pregnant women with periodontitis and pregnant women with a healthy periodontium. We also determined the prevalence of periodontitis among pregnant women attending Omdurman Midwifery Hospital. MaterialsThis was a hospital-based clinical study and laboratory investigation using ELISA tests of 80 pregnant women in the third trimester conducted at the Omdurman Midwifery Hospital in Khartoum, Sudan. The study group consisted of 50 women while the control group consisted of 30 women. ResultsIndependent samples t-tests were used to compare serum and GCF levels of IL-1β between the study and control groups. Pearson's correlation analysis was also used to compare gingival parameters and IL-1β levels in the GCF. For each comparison, the p-value was fixed at 0.05. The GCF in the research group showed a considerable increase in IL-1β levels. There was also a strong positive association between high IL-1β levels in the research group's GCF and probing pocket depth (PPD) and clinical attachment level (CAL) levels. ConclusionsOur study provides further evidence that periodontitis, as measured by a PD ≥4 mm and a CAL ≥3 mm, is associated with an increased level of IL-1β in the GCF of pregnant women with active periodontal disease during pregnancy and may include the transient translocation of oral organisms to the utero-placental unit, inciting placental inflammation or oxidative stress early in pregnancy, ultimately resulting in placental damage and clinical manifestations.

Moringa oleifera Mouthwash Reinforced with Silver Nanoparticles - Preparation, Characterization and its Efficacy Against Oral Aerobic Microorganisms - In Vitro Study

Moringa oleifera (MO) commonly known as drumstick plant, is recognised by modern medicine for its distinctive therapeutic benefits. One of those benefits being its antimicrobial activity. Silver nanoparticles, known for its pharmacological effects as well as synergistic action with various agents have gained popularity in recent years. The aim of this research work was to assess the antibacterial efficacy of 5% Moringa oleifera mouthwash reinforced with silver nanoparticles against oral aerobic organisms. Aqueous extract of 5% Moringa oleifera was used to synthesize silver nanoparticles and prepare the mouthwash. Characterization was done using scanning electron microscopy analysis and energy dispersive x-ray analysis. The antibacterial activity of the mouthwash against Streptococcus mutans, Staphylococcus aureus, Enterococcus faecalis, Candida albicans was investigated using agar well diffusion assay. 5% MO - silver nanoparticles mouthwash had a stronger impact on Staphylococcus aureus and a comparable effect on Streptococcus mutans. The maximum zone of inhibition was 28 mm at 100 µL for Staphylococcus aureus and minimum zone of inhibition was 16mm for Candida albicans. There was a dose dependent effect of MO - silver nanoparticles mouthwash on Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis and Candida albicans. Of these, the antimicrobial effect was more appreciable on plaque colonizers like Staphylococcus aureus and Streptococcus mutans. Thus, these characteristics of phytomedicine and nanomedicine prove to be a safer alternative in the management of Plaque associated Gingival diseases.

Antimicrobial susceptibilities and mechanisms of resistance of commensal and invasive Mycoplasma salivarium isolates.

Mycoplasma salivarium, an oral commensal organism, can cause severe invasive infections in immunocompromised individuals. Currently there is no treatment guidance for such infections. We performed antimicrobial susceptibility tests on 39 commensal and invasive M. salivarium isolates and investigated the mechanisms of antimicrobial resistance. Clindamycin was the most active agent [minimum inhibition concentration (MIC) range: 0.004–128 mg/L, MIC50 = 0.031 mg/L, MIC90 = 0.125 mg/ml], followed by tetracycline and levofloxacin. All isolates were resistant to erythromycin (MIC ≥4 mg/L) due to the presence of 2057A (Escherichia coli numbering) in 23S rRNA. Three isolates with elevated clindamycin MICs (≥8 mg/L) harbored A2058T/G mutations in 23S rRNA gene; four sequential isolates from one patient developed C2611T and A2059G mutations accompanying the increase of clindamycin MICs. Five isolates with elevated tetracycline MICs (≥4 mg/L) had mutations in 16S rRNA gene (A965G/T, G966T, or A967C/T) and one of them harbored TetM. Nine isolates with elevated levofloxacin MICs (≥4 mg/L) had one or more mutations in gyrA, gyrB, parC, or parE. Susceptibility breakpoints for clindamycin, tetracycline and levofloxacin were suggested to be ≤0.125, ≤2, and ≤2 mg/L, respectively. Antimicrobial resistance to any of the three agents (clindamycin, tetracycline, or levofloxacin) was documented in 12 (34.3%) non-duplicate isolates, of which 10 were invasive. Levofloxacin resistance was most frequent (25.7%). Multi-drug resistance was also observed (14.3%). This study demonstrates the frequent occurrence of antimicrobial resistance in M. salivarium, emphasizing the need for culture and susceptibility testing to guide antimicrobial therapy.

Cytologic detection of Simonsiella‐like bacteria suggesting oral contamination in cases of canine ulcerative keratitis

AbstractSimonsiella is a known oral commensal organism and has been identified as a part of the normal ocular microbiota in humans. This case series highlights three cases of canine ulcerative keratitis in which a mixed bacterial infection, including high numbers of Simonsiella spp. had been identified cytologically. All cases had episodes of oral contamination, either from licking the eye, licking the paws and rubbing the eye, or housemate(s) licking the eye. In two of three cases, ulcer resolution was observed within 3 weeks following initiation of broad‐spectrum topical antimicrobial therapy.

Bifidobacterium Strains Present Distinct Effects on the Control of Alveolar Bone Loss in a Periodontitis Experimental Model.

Periodontitis is an inflammatory disease induced by a dysbiotic oral microbiome. Probiotics of the genus Bifidobacterium may restore the symbiotic microbiome and modulate the immune response, leading to periodontitis control. We evaluated the effect of two strains of Bifidobacterium able to inhibit Porphyromonas gingivalis interaction with host cells and biofilm formation, but with distinct immunomodulatory properties, in a mice periodontitis model. Experimental periodontitis (P+) was induced in C57Bl/6 mice by a microbial consortium of human oral organisms. B. bifidum 1622A [B+ (1622)] and B. breve 1101A [B+ (1101)] were orally inoculated for 45 days. Alveolar bone loss and inflammatory response in gingival tissues were determined. The microbial consortium induced alveolar bone loss in positive control (P + B-), as demonstrated by microtomography analysis, although P. gingivalis was undetected in oral biofilms at the end of the experimental period. TNF-α and IL-10 serum levels, and Treg and Th17 populations in gingiva of SHAM and P + B- groups did not differ. B. bifidum 1622A, but not B. breve 1101A, controlled bone destruction in P+ mice. B. breve 1101A upregulated transcription of Il-1β, Tnf-α, Tlr2, Tlr4, and Nlrp3 in P-B+(1101), which was attenuated by the microbial consortium [P + B+(1101)]. All treatments downregulated transcription of Il-17, although treatment with B. breve 1101A did not yield such low levels of transcripts as seen for the other groups. B. breve 1101A increased Th17 population in gingival tissues [P-B+ (1101) and P + B+ (1101)] compared to SHAM and P + B-. Administration of both bifidobacteria resulted in serum IL-10 decreased levels. Our data indicated that the beneficial effect of Bifidobacterium is not a common trait of this genus, since B. breve 1101A induced an inflammatory profile in gingival tissues and did not prevent alveolar bone loss. However, the properties of B. bifidum 1622A suggest its potential to control periodontitis.

Oral Microbiota Variation: A Risk Factor for Development and Poor Prognosis of Esophageal Cancer

Recent studies have shown that oral microbiota play an important role in the esophageal cancer (EC) initiation and progression, suggesting that oral microbiota is a new risk factor for EC. The composition of the microbes inhabiting the oral cavity could be perturbed with continuous factors such as smoking, alcohol consumption, and inflammation. The microbial alteration involves the decrease of beneficial species and the increase of pathogenic species. Experimental evidences suggest a significant role of oral commensal organisms in protecting hosts against EC. By contrast, oral pathogens, especially Porphyromonas gingivalis and Fusobacterium nucleatum, give rise to the risk for developing EC through their pro-inflammatory and pro-tumorigenic activities. The presences of oral dysbiosis, microbial biofilm, and periodontitis in EC patients are found to be associated with invasive cancer phenotypes and poor prognosis. The mechanism of oral bacteria in EC progression is complex, which involves a combination of cytokines, chemokines, oncogenic signaling pathways, cell surface receptors, the degradation of extracellular matrix, and cell apoptosis. From a clinical perspective, good oral hygiene, professional oral care, and rational use of antibiotics bring positive impacts on oral microbial balance, thus helping individuals reduce the risk of EC, inhibiting postoperative complications among EC patients, and improving the efficiency of chemoradiotherapy. However, current oral hygiene practices mainly focus on the oral bacteria-based predictive and preventive purposes. It is still far from implementing microbiota-dependent regulation as a therapy for EC. Further explorations are needed to render oral microbiota a potential target for treating EC.

#81: Care Process Measures and Outcomes of Percutaneous Pulmonary Valve Implantation-associated Infective Endocarditis

Abstract Background Percutaneous pulmonary valve implantation (PPVI) is being increasingly used as a minimally invasive corrective procedure for right ventricular outflow tract (RVOT) dysfunction. Ten-year survival following PPVI is estimated at over 90% due to the durability of the various bioprosthetic valves. However, infective endocarditis (IE) remains a potential complication of such valves with significant morbidity and mortality. We evaluated the presenting symptoms, clinical features, pathogens, and outcomes of patients with IE following PPVI to identify opportunities to improve early diagnosis and management. Methods A convenience sample of patients at a large Pediatric Cardiology practice in Northern Virginia was queried for PPVI and IE from January 1, 2016, to June 30, 2019. Manual chart review was done to extract clinical points of interest and descriptive analyses were performed. Patients were classified as having IE per modified Duke’s criteria. Results We identified 14 patients who underwent PPVI. Five of these patients (36%) developed IE. All IE patients had underlying Tetralogy of Fallot and none had previous episodes of IE. 60% of patients with IE were male with a median age of 26 years old (IQR 20–30). Four IE patients had a Melody valve and 1 had a SAPIEN valve. The median elapsed time between PPVI and IE diagnosis was 128 days (IQR 32–391) with a median duration of illness prior to the diagnosis of IE of 6 days (IQR 5–9). All IE patients had to present fever. 40% of IE patients had to present chest pain and 20% had presenting musculoskeletal pain. All IE patients had an elevated initial C-reactive protein (CRP) with a median value of 13.1 mg/dL (IQR 12.5–15.2). The median initial white blood cell count was 9.3 × 103/μL (IQR 8.1–10.3). The median duration of bacteremia was 1 day (IQR 1–2). A pathogen was recovered in all five IE patients with different organisms amongst the patients: coagulase-negative Staphylococcus species were recovered in patients who developed IE within 60 days from PPVI (Staphylococcus lugdunensis and Staphylococcus epidermidis) whereas coagulase-negative Staphylococcus species and oral commensal organisms were found in IE patients beyond 60 days from PPVI (Staphylococcus sanguinis, Gamella haemolysans, and Neisseria elongata). The initial echocardiogram did not show vegetations in any of the patients and 40% went on to have sternotomy with valve replacement. There were no deaths. Conclusions With an increase in PPVI, clinicians should have a high index of suspicion for IE in patients with underlying Tetralogy of Fallot who present with fever and elevated CRP, regardless of elapsed time from PPVI or valve type. Empiric antimicrobial therapy for suspected IE following PPVI should remain broad with other possible pathogens beyond coagulase-negative Staphylococcus species.

Evaluation of Empiric Vancomycin for Fevers During High-dose Cytarabine Administration.

Cytarabine is a nucleoside analog used in chemotherapy regimens for the treatment of multiple hematologic malignancies. One of the known adverse effects of cytarabine, particularly in patients receiving high-dose cytarabine (HDAC), is drug-induced fever. Multiple studies have demonstrated an increased risk of viridans group streptococcal bacteremia in patients who have received HDAC. For this reason, our institution and several other institutions across the country routinely include vancomycin as empiric coverage for patients who develop fever during HDAC, due to concern for resistance to cephalosporin monotherapy. Patient demographic, diagnosis, treatment, and outcome information was collected by electronic chart review for each HDAC infusion from 2007 to August 2018 at the University of Iowa Stead Family Children's Hospital. If fever was documented during or within 24 hours of HDAC, additional information was collected regarding patient outcome and diagnostic testing. Of 208 HDAC administrations documented, patients developed fevers during the course on 82 occasions (39.4%). A median of 3 blood cultures per febrile period were obtained from time of fever onset during HDAC administration through >24 hours afebrile. One blood culture was positive for an oral flora organism determined by the microbiology lab report to be a likely contaminant. There were no other positive blood cultures in non-neutropenic or neutropenic patients. Fever due to HDAC is relatively common but appears to frequently lack association with bacteremia during the time of HDAC administration. Broad-spectrum empiric antibiotic regimens including vancomycin may be unnecessary for these patients, particularly before they become neutropenic.

In This Issue

In This Issue

The Oral Microbiota: a Literature Review for Updating Professionals in Dentistry-Part II

In the first part of this literature review, published in October 2019 in this journal, we summarized the conceptual background of the oral microbiota, and the main methods used in microbiology to characterize oral organisms. We also presented the most studied bacteria species in the oral microbiota. In this second part, we will discuss the evidence regarding the biological plausibility linking the oral microbiota dysbiosis and systemic diseases, as well as the main factors and mechanisms suspected in this association.

Minimum Inhibitory and Fungicidal Concentration Tests Of Snakehead Fish (Channa Striata) Oil Extracts Against Candida Albicans: An In Vitro Study

Introduction: Candida albicans (C. Albicans) is an oral cavity commensal organism that can shift into a pathogenic form under certain conditions. Nowadays, natural substances used as an alternative for a new antifungal agent. Snakehead fish oil extracts have been reported to have antifungal effect i.e; unsaturated fatty acids such as Omega-3 and Omega-6. The purpose of this study was to investigate the antifungal activity of snakehead fish oil extracts against C. Albicans. Materials and Methods: An in vitro laboratory study with a posttest control group design was established. To produce the snakehead fish oil extracts, wet rendering method was used. The snakehead fish oil extracts then tested with microdilution method to determine Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) against C. Albicans. An 0,062-32 μl/ml concentrations used for the microdilution test and 2-32 μl/ml for the disc-diffusion test. Nystatin (100 μg/ml) was used as the positive control. Results: There were visible growths and no inhibition zone in all concentrations of snakehead fish oil extracts. Conclusion: 0.062-32 μl/ml concentrations of Snakehead fish oil extracts did not have the abilities to decrease the growth of C. albicans.

A novel phosphoglycerol serine-glycine lipodipeptide of Porphyromonas gingivalis is a TLR2 ligand

Porphyromonas gingivalis is a Gram-negative anaerobic periodontal microorganism strongly associated with tissue-destructive processes in human periodontitis. Following oral infection with P. gingivalis, the periodontal bone loss in mice is reported to require the engagement of Toll-like receptor 2 (TLR2). Serine-glycine lipodipeptide or glycine aminolipid classes of P. gingivalis engage human and mouse TLR2, but a novel lipid class reported here is considerably more potent in engaging TLR2 and the heterodimer receptor TLR2/TLR6. The novel lipid class, termed Lipid 1256, consists of a diacylated phosphoglycerol moiety linked to a serine-glycine lipodipeptide previously termed Lipid 654. Lipid 1256 is approximately 50-fold more potent in engaging TLR2 than the previously reported serine-glycine lipid classes. Lipid 1256 also stimulates cytokine secretory responses from peripheral blood monocytes and is recovered in selected oral and intestinal Bacteroidetes organisms. Therefore, these findings suggest that Lipid 1256 may be a microbial TLR2 ligand relevant to chronic periodontitis in humans.

Garcinoic Acids and a Benzophenone Derivative from the Seeds of Garcinia kola and Their Antibacterial Activities against Oral Bacterial Pathogenic Organisms.

In this study, three new garcinoic acid dimers, δ,δ-bigarcinoic acid (1), δ,δ-bi-O-garcinoic acid (2), and γ,δ-bi-O-garcinoic acid (3), and a new benzophenone derivative, (8E)-4-geranyl-3,5-dihydroxybenzophenone (4), as well as seven known compounds (5-11) were isolated from the seeds of Garcinia kola. The structures of the new compounds were elucidated using MALDI-TOF-MS and spectroscopic data, including 1D and 2D NMR and electronic circular dichroism spectra. All of the isolated compounds were evaluated for their antimicrobial activity against two oral pathogens, Porphyromonas gingivalis and Streptococcus sobrinus. Among them, 4 and δ-garcinoic acid (6) exhibited antimicrobial activity against both of these microorganisms (MICs of 31.3-62.5 μM for P. gingivalis and 15.6-31.3 μM for S. sobrinus). These results indicate that some chemical constituents in G. kola seeds have potential application in the prevention of oral diseases.

Screening of Punica granatum extract for antimicrobial activity against oral micro organisms

Background and Objectives: A lot of research work in both dental and medical fields support the curative properties of pomegranate. Accordingly, it was decided to prepare a pomegranate mouthwash and evaluate it among Dental patients diagnosed with Chronic Gingivitis. The objective of the present invitro study is to assess the Minimum Inhibitory Concentration (MIC) of the commercially available pomegranate extract powder against few oral pathogenic microorganisms. Methodology: Serial dilution method using thioglycolate broth medium was used for anerobes like Streptococcus mutans, Fusobacterium nucleatum, Aggregatibacter actinomycetomcomitans, Prevotella intermedia and Mueller hinton agar mediated growth was used for aerobe like Staphylococcus aureus. Following which microdilution assay was performed and accordingly evaluated the MIC. Based on this report, the test rinse was prepared and further evaluated using the same methodology for both aerobes and anerobes. Results and Inference: It was observed from the MIC report for both aerobes and anerobes that at a concentration of 0.2% the formulated mouth rinse was effective against all the chosen organisms. The results of the study infer that products like mouthwash, dental gels etc made from this concentration could be possibly used for the control of dental infections.

Improving Oral Health and Modulating the Oral Microbiome to Reduce Bloodstream Infections from Oral Organisms in Pediatric and Young Adult Hematopoietic Stem Cell Transplantation Recipients: A Randomized Controlled Trial.

Bloodstream infections (BSIs) from oral organisms are a significant cause of morbidity and mortality in hematopoietic stem cell transplantation (HSCT) recipients. There are no proven strategies to decrease BSIs from oral organisms. The aim of this study was to evaluate the impact of daily xylitol wipes in improving oral health, decreasing BSI from oral organisms, and modulating the oral microbiome in pediatric HSCT recipients. This was a single-center 1:1 randomized controlled trial in pediatric HSCT recipients age >2 years. Age-matched healthy children were enrolled to compare the oral microbiome. The oral hygiene standard of care (SOC) group continued to receive the standard oral hygiene regimen. The xylitol group received daily oral xylitol wipes (with .7 g xylitol) in addition to the SOC. The intervention started from the beginning of the transplantation chemotherapy regimen and extended to 28 days following transplantation. The primary outcome was oral health at interval time points, and secondary outcomes included BSIs from oral organisms in the first 30 days following transplantation, oral microbiome abundance, and diversity and oral pathogenic organism abundance. The study was closed early due to efficacy after an interim analysis of the first 30 HSCT recipients was performed (SOC group, n=16; xylitol group, n=14). The xylitol group had a significantly lower rate of gingivitis at days 7, 14, and 28 following transplantation (P=.031, .0039, and .0005, respectively); oral plaque at days 7 and 14 (P=.045 and .0023, respectively); and oral ulcers >10 mm at day 14 (P=.049) compared with the SOC group. The xylitol group had no BSI from oral organisms compared with the SOC group, which had 4 (P=.04). The xylitol group had significantly lower abundance of potential BSI pathogens, such as Staphylococcus aureus (P=.036), Klebsiella pneumoniae (P=.033), and Streptococcus spp (P=.011) at the day after transplantation compared with the SOC group. Healthy children and young adults had significantly increased oral microbiome diversity compared with all HSCT recipients (P < .001). The addition of xylitol to standard oral care significantly improves oral health, decreases BSI from oral organisms, and decreases the abundance of pathogenic oral organisms in pediatric and young adult HSCT recipients.

Mechanisms underlying the association between periodontitis and atherosclerotic disease.

Atherosclerosis is central to the pathology of cardiovascular diseases, a group of diseases in which arteries become occluded with atheromas that may rupture, leading to different cardiovascular events, such as myocardial infarction or ischemic stroke. There is a large body of epidemiologic and animal model evidence associating periodontitis with atherosclerotic disease, and many potential mechanisms linking these diseases have been elucidated. This chapter will update knowledge on these mechanisms, which generally fall into 2 categories: microbial invasion and infection of atheromas; and inflammatory and immunologic. With respect to the invasion and infection of atheromas, it is well established that organisms from the subgingival biofilm can enter the circulation and lodge in most distant tissues. Bacteremias resulting from oral interventions, and even oral hygiene activities, are well documented. More recently, indirect routes of entry of oral organisms (via phagocytes or dendritic cells) have been described for many oral organisms, into many tissues. Such organisms include the periodontal pathogens Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Tannerella forsythia, and Fusobacterium nucleatum. Intracellular survival of these organisms with dissemination to distant sites (The Trojan Horse approach) has been described. Their relative contribution to atheroma formation and progression has been studied mainly in experimental research, with results demonstrating that these organisms can invade endothelial cells and phagocytic cells within the atheroma, leading to pathogenic changes and progression of the atheroma lesion. The second category of mechanisms potentially linking periodontitis to atherosclerosis includes the dumping of inflammatory mediators originating from periodontal lesions into the systemic circulation. These inflammatory mediators, such as C-reactive protein, matrix metalloproteinases, fibrinogen, and other hemostatic factors, would further accelerate atheroma formation and progression, mainly through oxidative stress and inflammatory dysfunction. Moreover, direct effects on lipid oxidation have also been described. In summary, the evidence supports the concept that periodontitis enhances the levels of systemic mediators of inflammation that are risk factors for atherosclerotic diseases.

Microbiologically Documented Bloodstream Infection in Children With Malignancies: A Single-center Experience.

Bloodstream infection (BSI) remains a considerable cause of morbidity and mortality for cancer patients. With a better understanding of it, better methods can be used. The primary objective of this study was to describe the characteristics of BSIs in our institution, and the second was to determine the possible risk factors associated with them. Data of cancer patients from 2009 to 2015 at our institution were included. Medical information and blood cultures were analyzed to determine the BSI rate. The χ and Fisher exact tests were used for categorical data and to determine risk factors associated with BSIs and pathogens. A total of 565 (8.6%) events were diagnosed with BSIs. Although Gram-negative bacteria (52.6%) were the most commonly isolated pathogens, Gram-positive microorganisms (45.0%) were also prevalent. Oral and gastrointestinal organisms were common. Pathogens were more likely to be identified in patients with central venous catheters and in patients with prolonged neutropenia (P<0.05). This study provides updated epidemiology in BSIs and helps with the prevention and management of suspected BSIs in vulnerable patients. Better anti-infection therapy could be provided to these patients based on the isolated pathogens.