Experimental transient bacteraemias in human subjects with clinically healthy gingivae

Manganese Depletion Leads to Multisystem Changes in the Transcriptome of the Opportunistic Pathogen Streptococcus sanguinis

Streptococcus sanguinis is a primary colonizer of teeth and is typically considered beneficial due to its antagonistic relationship with the cariogenic pathogen Streptococcus mutans. However, S. sanguinis can also act as an opportunistic pathogen should it enter the bloodstream and colonize a damaged heart valve, leading to infective endocarditis. Studies have implicated manganese acquisition as an important virulence determinant in streptococcal endocarditis. A knockout mutant lacking the primary manganese import system in S. sanguinis, SsaACB, is severely attenuated for virulence in an in vivo rabbit model. Manganese is a known cofactor for several important enzymes in S. sanguinis, including superoxide dismutase, SodA, and the aerobic ribonucleotide reductase, NrdEF. To determine the effect of manganese depletion on S. sanguinis, we performed transcriptomic analysis on a ΔssaACB mutant grown in aerobic fermentor conditions after the addition of the metal chelator EDTA. Despite the broad specificity of EDTA, analysis of cellular metal content revealed a decrease in manganese, but not in other metals, that coincided with a drop in growth rate. Subsequent supplementation with manganese, but not iron, zinc, or magnesium, restored growth in the fermentor post-EDTA. Reduced activity of Mn-dependent SodA and NrdEF likely contributed to the decreased growth rate post-EDTA, but did not appear entirely responsible. With the exception of the Dps-like peroxide resistance gene, dpr, manganese depletion did not induce stress response systems. By comparing the transcriptome of ΔssaACB cells pre- and post-EDTA, we determined that manganese deprivation led to altered expression of diverse systems. Manganese depletion also led to an apparent induction of carbon catabolite repression in a glucose-independent manner. The combined results suggest that manganese limitation produces effects in S. sanguinis that are diverse and complex, with no single protein or system appearing entirely responsible for the observed growth rate decrease. This study provides further evidence for the importance of this trace element in streptococcal biology. Future studies will focus on determining mechanisms for regulation, as the multitude of changes observed in this study indicate that multiple regulators may respond to manganese levels.

Contemporary practices for mechanical oral hygiene to prevent periodontal disease

It is well established that dental plaque on teeth leads to gingivitis and periodontitis, and that several mechanical and chemical methods of plaque control can prevent gingivitis. The aim of the current review is to summarize and synthesize the available scientific evidence supporting practices for mechanical oral hygiene to prevent periodontal diseases. Evidence for contemporary practices of mechanical oral hygiene to prevent periodontal disease relies on studies of gingivitis patients. General recommendations concerning the ideal oral hygiene devices and procedures are still inconclusive. However, toothbrushing and interdental cleaning remain the mainstays of prevention of periodontal diseases. The primary approach requires individually tailored instruction for implementation of a systematic oral hygiene regimen.

Genomic, Phenotypic, and Virulence Analysis of Streptococcus sanguinis Oral and Infective-Endocarditis Isolates

Streptococcus sanguinis, an abundant and benign inhabitant of the oral cavity, is an important etiologic agent of infective endocarditis (IE), particularly in people with predisposing cardiac valvular damage. Although commonly isolated from patients with IE, little is known about the factors that make any particular S. sanguinis isolate more virulent than another or, indeed, whether significant differences in virulence exist among isolates. In this study, we compared the genomes of a collection of S. sanguinis strains comprised of both oral isolates and bloodstream isolates from patients diagnosed with IE. Oral and IE isolates could not be distinguished by phylogenetic analyses, and we did not succeed in identifying virulence genes unique to the IE strains. We then investigated the virulence of these strains in a rabbit model of IE using a variation of the Bar-seq (barcode sequencing) method wherein we pooled the strains and used Illumina sequencing to count unique barcodes that had been inserted into each isolate at a conserved intergenic region. After we determined that several of the genome sequences were misidentified in GenBank, our virulence results were used to inform our bioinformatic analyses, identifying genes that may explain the heterogeneity in virulence. We further characterized these strains by assaying for phenotypes potentially contributing to virulence. Neither strain competition via bacteriocin production nor biofilm formation showed any apparent relationship with virulence. Increased cell-associated manganese was, however, correlated with blood isolates. These results, combined with additional phenotypic assays, suggest that S. sanguinis virulence is highly variable and results from multiple genetic factors.

Periodontal bacterial invasion and infection: contribution to atherosclerotic pathology

OBJECTIVE

The objective of this review was to perform a systematic evaluation of the literature reporting current scientific evidence for periodontal bacteria as contributors to atherosclerosis.

METHODS

Literature from epidemiological, clinical and experimental studies concerning periodontal bacteria and atherosclerosis were reviewed. Gathered data were categorized into seven "proofs" of evidence that periodontal bacteria: 1) disseminate from the oral cavity and reach systemic vascular tissues; 2) can be found in the affected tissues; 3) live within the affected site; 4) invade affected cell types in vitro; 5) induce atherosclerosis in animal models of disease; 6) non-invasive mutants of periodontal bacteria cause significantly reduced pathology in vitro and in vivo; and 7) periodontal isolates from human atheromas can cause disease in animal models of infection.

RESULTS

Substantial evidence for proofs 1 to 6 was found. However, proof 7 has not yet been fulfilled.

CONCLUSIONS

Despite the lack of evidence that periodontal bacteria obtained from human atheromas can cause atherosclerosis in animal models of infection, attainment of proofs 1 to 6 provides support that periodontal pathogens can contribute to atherosclerosis.

Periodontal bacterial invasion and infection: contribution to atherosclerotic pathology

OBJECTIVE

The objective of this review was to perform a systematic evaluation of the literature reporting current scientific evidence for periodontal bacteria as contributors to atherosclerosis.

METHODS

Literature from epidemiological, clinical and experimental studies concerning periodontal bacteria and atherosclerosis were reviewed. Gathered data were categorized into seven "proofs" of evidence that periodontal bacteria: 1) disseminate from the oral cavity and reach systemic vascular tissues; 2) can be found in the affected tissues; 3) live within the affected site; 4) invade affected cell types in vitro; 5) induce atherosclerosis in animal models of disease; 6) non-invasive mutants of periodontal bacteria cause significantly reduced pathology in vitro and in vivo; and 7) periodontal isolates from human atheromas can cause disease in animal models of infection.

RESULTS

Substantial evidence for proofs 1 to 6 was found. However, proof 7 has not yet been fulfilled.

CONCLUSIONS

Despite the lack of evidence that periodontal bacteria obtained from human atheromas can cause atherosclerosis in animal models of infection, attainment proofs 1 to 6 provides support that periodontal pathogens can contribute to atherosclerosis.

Microbiological Contamination of Drugs during Their Administration for Anesthesia in the Operating Room

Background

The aseptic techniques of anesthesiologists in the preparation and administration of injected medications have not been extensively investigated, but emerging data demonstrate that inadvertent lapses in aseptic technique may be an important contributor to surgical site and other postoperative infections.

Methods

A prospective, open, microbiological audit of 303 cases in which anesthesiologists were asked to inject all bolus drugs, except propofol and antibiotics, through a 0.2-µm filter was performed. The authors cultured microorganisms, if present, from the 0.2-µm filter unit and from the residual contents of the syringes used for drawing up or administering drugs. Participating anesthesiologists rated ease of use of the filters after each case.

Results

Twenty-three anesthesiologists each anesthetized up to 25 adult patients. The authors isolated microorganisms from filter units in 19 (6.3%) of 300 cases (3 cases were excluded), including Staphylococcus capitis, Staphylococcus warneri, Staphylococcus epidermidis, Staphylococcus haemolyticus, Micrococcus luteus/lylae, Corynebacterium, and Bacillus species. The authors collected used syringes at the end of each case and grew microorganisms from residual drug in 55 of these 2,318 (2.4%) syringes including all the aforementioned microorganisms and also Kocuria kristinae, Staphylococcus aureus, and Staphylococcus hominus. Participants’ average rating of ease of use of the filter units was 3.5 out of 10 (0 being very easy and 10 being very difficult).

Conclusions

Microorganisms with the potential to cause infection are being injected (presumably inadvertently) into some patients during the administration of intravenous drugs by bolus during anesthesia. The relevance of this finding to postoperative infections warrants further investigation.

Prevention of Orthopaedic Implant Infection in Patients Undergoing Dental Procedures

The Prevention of Orthopaedic Implant Infection in Patients Undergoing Dental Procedures evidence-based clinical practice guideline was codeveloped by the American Academy of Orthopaedic Surgeons (AAOS) and the American Dental Association. This guideline replaces the previous AAOS Information Statement, "Antibiotic Prophylaxis in Bacteremia in Patients With Joint Replacement," published in 2009. Based on the best current evidence and a systematic review of published studies, three recommendations have been created to guide clinical practice in the prevention of orthopaedic implant infections in patients undergoing dental procedures. The first recommendation is graded as Limited; this recommendation proposes that the practitioner consider changing the long-standing practice of routinely prescribing prophylactic antibiotic for patients with orthopaedic implants who undergo dental procedures. The second, graded as Inconclusive, addresses the use of oral topical antimicrobials in the prevention of periprosthetic joint infections. The third recommendation, a Consensus statement, addresses the maintenance of good oral hygiene.

Oral health status among hospitalized patients

AIM

To investigate into oral health status and its association with health status in hospitalized patients.

METHODS

A total of 82 patients were examined and 49 (59.7%) patients were men. The patients answered a survey and oral examinations to detect the number of teeth, oral hygiene index, prostheses hygiene, oral lesions, caries, dental plaque index (DPI), gingival inflammation index (GI), gingival bleeding index, periodontitis and periodontal index.

RESULTS

Oral hygiene was associated with age, but it was not related to physical disability. Difficulty eating was mainly associated with age and tooth loss. All full and partially dentate patients presented dental plaque, 38 (69%) poor oral hygiene, 58 (98.1%) gingival inflammation, 41 (74.5%) periodontal disease and 33 (60%) caries. Oral lesions were detected in 30 (36.5%) and candidiasis (n = 16, 19.6%) was the most frequent mucous lesion. Caries were associated with smoking and poor oral hygiene. Hospital length of stay and age were associated with increased DPI and GI.

CONCLUSIONS

The majority of hospitalized patients did not present satisfactory oral hygiene. Caries and periodontal diseases are associated with health behaviours. Increased time length at hospital could increase gingival inflammation and dental plaque accumulation.

Bacteraemia due to dental flossing

AIMS

The aims of this study were to (1) investigate the incidence of bacteraemia following flossing in subjects with chronic periodontitis or periodontal health; (2) identify the micro-organisms in detected bacteraemias; and (3) identify any patient or clinical factors associated with such bacteraemia.

MATERIAL AND METHODS

Baseline blood samples were obtained from 30 individuals with chronic periodontitis (17 M:13 F, 29-75 years) and 30 with periodontal health (17 M:13 F, 28-71 years) following a non-invasive examination. Each subject's teeth were then flossed in a standardized manner and blood samples obtained 30 s and 10 min. after flossing cessation. Blood samples were cultured in a BACTEC system and positive samples subcultured for identification.

RESULTS

Forty per cent of periodontitis subjects and 41% of periodontally healthy subjects tested positive for bacteraemia following flossing. Viridans streptococci, which are commonly implicated in infective endocarditis (IE), were isolated from 19% of positive subjects and accounted for 35% of microbial isolates. Twenty per cent of subjects had a detectable bacteraemia at 10 min. post-flossing. No patient or clinical factors were significantly associated with post-flossing bacteraemia.

CONCLUSIONS

Dental flossing can produce bacteraemia in periodontally healthy and periodontally diseased individuals at a rate comparable with that caused by some dental treatments for which antibiotic prophylaxis is given to prevent IE.

Position Paper: The Role of Supra- and Subgingival Irrigation in the Treatment of Periodontal Diseases

This position paper addresses the role of supra- and subgingival irrigation in the treatment of periodontal diseases. It was prepared by the Committee on Research, Science and Therapy of the American Academy of Periodontology. The document is divided into two portions, consisting of supragingival irrigation and subgingival irrigation. In their respective segments, these treatment techniques are assessed as monotherapies and as adjuncts to conventional treatment. The conclusions drawn in this paper represent the position of the American Academy of Periodontology regarding irrigation therapy in the treatment of periodontal diseases.

White blood cell count in generalized aggressive periodontitis after non-surgical therapy

BACKGROUND

Periodontal bacteria are known to invade the systemic circulation. Chronic low-level bacteremia and a systemic inflammatory response have been suggested as a pathogenetic link between periodontal disease and atherosclerosis. The purpose of this study was to examine the systemic effect of a non-surgical therapy on white blood cell count (WBC count) and differential blood count in smoking and non-smoking generalized aggressive periodontitis (GAP) patients.

METHODS

27 adult periodontitis patients (13 smokers and 14 non-smokers) with previously untreated GAP were subjected to 3 sessions of oral hygiene procedure. Afterwards, the patients were treated by scaling and root planing under local anaesthesia. Periodontal examinations were performed after supragingival pretreatment and three months after subgingival therapy. Pocket probing depth (PPD) and relative attachment level (RAL) were measured with Florida probe and disc probe. Accompanying clinical evaluation venous blood samples were taken to analyse the WBC counts and differential blood counts. For statistical analysis non-parametric tests were utilized.

RESULTS

No clinical or demographic differences were found between smokers (n=13) and non-smokers (n=14). PPD, bleeding on probing (BoP) and suppuration improved significantly after therapy both in smokers and non-smokers. Following periodontal treatment WBC counts, neutrophil and platelet counts decreased significantly in non-smokers (p< or =0.004), while in smokers only platelet counts were significantly reduced (p=0.006). Non-smokers showed a significantly higher reduction of WBC counts (p=0.005) and neutrophils (p=0.001) compared to smokers.

CONCLUSION

The results indicate that a therapeutical intervention may have a systemic effect on the blood count in GAP patients. This effect seems to differ between smokers and non-smokers.

The effects of toothpastes on the residual microbial contamination of toothbrushes

BACKGROUND

Contaminated toothbrushes have been shown to harbor and transmit viruses and bacteria. The authors conducted a study to evaluate the effect of a triclosan-containing toothpaste on the residual anaerobic microbial contamination of toothbrushes.

METHODS

Twenty patients who had Type III or Type IV periodontitis participated in this study. One side of each of their mouths served as a control (no toothpaste). The teeth on the other side were brushed with a regular toothpaste or a triclosan-containing toothpaste. After the toothbrushes were allowed to dry in air for four hours, the authors placed the toothbrush heads in solution, dislodged the microbes from the brushes by vortexing and plated them in culture dishes. The authors anerobically incubated the culture dishes and determined the presence or absence of Prevotella species or Ps; Porphyromonas gingivalis, or Pg; and Actinobacillus actinomycetemcomitans, or Aa.

RESULTS

The authors detected Aa and Pg on the control toothbrushes more frequently than they did Ps. This variation in isolation frequency was statistically significant by chi 2 analysis (P < .001). The authors compared the isolation frequency of the three test organisms between the control and regular-toothpaste groups, between the control and triclosan-containing--toothpaste groups, and between the triclosan-containing--toothpaste and regular-toothpaste groups. They found no significant intergroup differences in the isolation frequencies after using chi 2 analysis.

CONCLUSIONS

Toothpaste use reduced the residual microbial contamination for two of three test organisms, but the lower isolation frequencies were not statistically significant. Further study in this area is indicated.

CLINICAL IMPLICATIONS

Dental professionals should advise patients who have systemic, localized or oral inflammatory diseases to disinfect or frequently replace their toothbrushes.

Lipoxin A(4) analogues inhibit leukocyte recruitment to Porphyromonas gingivalis: a role for cyclooxygenase-2 and lipoxins in periodontal disease

The potential involvement of the inducible cyclooxygenase isoform (COX-2) and the role of novel lipid mediators were investigated in the pathogenesis of periodontal disease. Crevicular fluids from localized juvenile periodontitis (LJP) patients contained prostaglandin (PG)E(2) and 5-lipoxygenase-derived products, leukotriene B(4), and the biosynthesis interaction product, lipoxin (LX)A(4). Neutrophils from peripheral blood of LJP patients, but not from asymptomatic donors, also generated LXA(4), suggesting a role for this immunomodulatory molecule in periodontal disease. To characterize host responses of interest to periodontal pathogens, Porphyromonas gingivalis was introduced within murine dorsal air pouches. In the air pouch cavity, P. gingivalis elicited leukocyte infiltration, concomitant with elevated PGE(2) levels in the cellular exudates, and upregulated COX-2 expression in infiltrated leukocytes. In addition, human neutrophils exposed to P. gingivalis also upregulated COX-2 expression. Blood borne P. gingivalis gave significant increases in the murine tissue levels of COX-2 mRNA associated with both heart and lungs, supporting a potential role for this oral pathogen in the evolution of systemic events. The administration of metabolically stable analogues of LX and of aspirin-triggered LX potently blocked neutrophil traffic into the dorsal pouch cavity and lowered PGE(2) levels within exudates. Together, these results identify PMN as an additional and potentially important source of PGE(2) in periodontal tissues. Moreover, they provide evidence for a novel protective role for LX in periodontitis, limiting further PMN recruitment and PMN-mediated tissue injury that can lead to loss of inflammatory barriers that prevent systemic tissue invasion of oral microbial pathogens.

ADRF Trebitsch Scholarship. The microbial contamination of toothbrushes. A pilot study

Ten individuals were each supplied with a new toothbrush of the same type and brand, together with identical tubes of fluoridated toothpaste. After a three-week period, during which subjects were asked to follow their usual oral hygiene practices, the toothbrushes were collected and assayed for microbial contamination using a range of selective growth media. The total microbial load per toothbrush was found to be 10(4) to 10(5) colony forming units. Staphylococci were found on all toothbrushes and streptococci on all but one. These two genera were also quantitatively dominant. Candida, corynebacteria, pseudomonads and coliforms were identified in 70, 60, 50 and 30 per cent of toothbrushes, respectively. However, mutans streptococci, lactobacilli and black-pigmented Gram-negative anaerobic rods were not detected on any of the toothbrushes. For each individual, information on variables such as toothbrush rinsing practices and post-brushing storage methods and environment was collected. No obvious relationship between such variables and microbial load was apparent but it is suggested that more extensive studies are needed, taking into account additional parameters such as age and degree of toothbrush wear and the use of pre-brushing mouthwashes.

Infective endocarditis associated with orthodontic treatment: a case report

A case of acute bacterial endocarditis associated with orthodontic treatment is described and the problems associated with orthodontic treatment for 'at risk' patients are discussed. The American Heart Association recommendations for orthodontic patients are summarized, and the general recommendations of the Endocarditis Working Party of the British Society for Antimicrobial Chemotherapy are appended.

Hemianopsia from occipital lobe abscess after dental care

We treated four patients who developed a homonymous hemianopsia from a bacterial abscess in the occipital lobe of the brain. All four patients were treated successfully by surgical drainage of the abscess and administration of parenteral antibiotics for at least six weeks. Despite cure of the brain abscess, each patient was left with a permanent residual homonymous visual field defect. Cultures from the abscess fluid in three of the four patients grew oral flora. Moreover, each patient had a history of dental care two to four weeks before the onset of visual symptoms. A history of recent dental treatment in a patient with a new hemianoptic field defect should alert the ophthalmologist to the possibility of a bacterial abscess in the occipital lobe.

Organ distribution of gut-derived bacteria caused by bowel manipulation or ischemia

Translocation of carbon-14-labeled Escherichia coli from the gut was studied at the specified times in the following groups of rats: Group 1, 5 hours after ligation of the superior mesenteric artery; Group 2, 5 hours after laparotomy and exposure of the superior mesenteric artery with gentle removal and replacement of the intestines; and Group 3, 5 hours after handling but no surgical manipulation. Both living and dead bacteria were administered by means of gavage, and the effect of viability, intestinal ischemia without reperfusion, and bowel manipulation on the translocation of enteric bacteria was assessed. We demonstrated that (1) even gentle bowel manipulation causes bacteremia as great as that associated with ligation of the superior mesenteric artery; (2) dead E. coli are absorbed into the blood in the presence of bowel manipulation or ischemia but less effectively than are live E. coli; (3) live bacteria are found in highest concentration in the lung and in descending order in the liver, kidney, heart, and spleen; (4) dead bacteria absorbed from the gut are found in highest concentration in the kidney and the liver. Lesser amounts are found in the lung, spleen, and heart.

Toothbrushing and transient bacteremia in patients undergoing orthodontic treatment

A study was made to determine the extent of bacteremia experienced by patients undergoing orthodontic treatment with fixed appliances during periods of routine oral hygiene--namely, brushing the teeth. Sixteen orthodontic patients made up the population--11 who practiced good oral hygiene and five who demonstrated poor oral hygiene. Blood was drawn aseptically from the median cubital vein of the subjects before and 15 minutes after brushing the teeth. An aliquot of each blood specimen was added to separate blood culture bottles and incubated at 37 degrees C for a period of up to 5 days. Blood was also used to determine the immune status of the subjects. Anaerobic bacteria were recovered from the blood of nine of the 16 patients studied; aerobic bacteria were not recovered. A negative blood culture before brushing and positive blood culture after brushing were expected but did not occur. Some subjects showed bacteremia before brushing and a negative blood culture after brushing. Others showed bacteremia before and after brushing. The unexpected results could be attributed to the patients eating and/or brushing before starting the test. The study showed the capacity of specific anaerobic bacteria to remain in the bloodstream for a 15-minute period. It also demonstrated a presence of bacteria in the bloodstream before the test began.

Plaque and systemic disease: a reappraisal of the focal infection concept

The review presented here covers metastatic local and systemic disease secondary to the accumulation of plaque or the formation of other pathogenic microbial depots in the mouth. At least 3 pathways may link oral infection to secondary disease, to wit metastatic infection due to transient bacteremia, metastatic immunological injury, and metastatic toxic injury. The available evidence is presented and examples are provided. They concern among others such divergent diseases as acute bacterial myocarditis, infective endocarditis, brain abscess, uveitis and iridocyclitis, trigeminal and atypical facial neuralgia, unilateral facial paralysis, fever of "unknown' origin, and neutrophil dysfunction.

Ill effects of improper oral hygeine procedure

Improper use of the tools that prevent tooth decay and gingival disease can also produce harmful effects. For example, dental floss can cause inflammation; toothbrushes could cause abscesses; and water-irrigation devices might drive foreign material into soft tissue. This report discusses the effects of incorrect oral hygiene, the signs the practioner should notice, and the proper corrective steps. Although effective oral hygiene is essential for the maintenance of healthy teeth and supporting tissues, analysis of the literature and clinical observation suggested that six problem areas may be associated with common oral hygiene measures. --Overly vigorous toothbrushing or using the wrong type of brush for the technique often leads to cervical tooth abrasion, gingival irritation, and gingival recession, or all of these problems. --Uncontrolled or overly vigorous dental flossing may lead to irritation, ulceration, or defects of the gingiva. Proximal root surfaces are rarely abraded. --Dentifrices, mouthwashes, and chewing gum may elicit allergic or toxic reactions in susceptible persons. These reactions take a variety of traumatic injuries, especially if used at high pressure. Perhaps, detailed individual instruction should be given by dental personnel before use. --Abscess of gingival tissues may occur from implantation of fragments of such oral hygiene aids as toothbrush bristles and toothpicks. --Bacteria may enter the bloodstream during certain oral hygiene measures, especially in patients with advanced chronic gingival disease. The rate of occurrence is unknown because of conflicting results in different studies. These bacteremias are of concern to patients who have rheumatic heart disease, prosthetic heart valves, prosthetic joints, and renal dialysis shunts, or fistulas used in renal dialysis. A classification of oral hygiene-caused disorders is proposed, based on the injury and the causative agent.