Prevalence of Eikenella corrodens and Actinobacillus actinomycetemcomitans in the dental plaque of dogs

Antibiotic stewardship for reptiles

This review discusses the general principles underlying responsible antibiotic usage in reptiles. Very little evidence underlies antibiotic usage in reptiles, and there are no published guidelines for responsible antibiotic usage. A literature search was performed to review the evidence for bacterial involvement in the pathology of selected common diseases of reptiles, allowing the development of recommendations for responsible antibiotic treatment of those diseases.

Resolving the Contradictory Functions of Lysine Decarboxylase and Butyrate in Periodontal and Intestinal Diseases

Periodontal disease is a common, bacterially mediated health problem worldwide. Mastication (chewing) repeatedly traumatizes the gingiva and periodontium, causing traces of inflammatory exudate, gingival crevicular fluid (GCF), to appear in crevices between the teeth and gingiva. Inadequate tooth cleaning causes a dentally adherent microbial biofilm composed of commensal salivary bacteria to appear around these crevices where many bacteria grow better on GCF than in saliva. We reported that lysine decarboxylase (Ldc) from Eikenella corrodens depletes the GCF of lysine by converting it to cadaverine and carbon dioxide. Lysine is an amino acid essential for the integrity and continuous renewal of dentally attached epithelium acting as a barrier to microbial products. Unless removed regularly by oral hygiene, bacterial products invade the lysine-deprived dental attachment where they stimulate inflammation that enhances GCF exudation. Cadaverine increases and supports the development of a butyrate-producing microbiome that utilizes the increased GCF substrates to slowly destroy the periodontium (dysbiosis). A long-standing paradox is that acid-induced Ldc and butyrate production support a commensal (probiotic) microbiome in the intestine. Here, we describe how the different physiologies of the respective tissues explain how the different Ldc and butyrate functions impact the progression and control of these two chronic diseases.

Dental Plaque Flora of the Dog with Reference to Fastidious and Anaerobic Bacteria Associated with Bites

Animal bite wounds are amongst the most common types of traumatic injuries in humans. The organisms isolated from these wounds generally reflect the oral flora of the biting animal and may be fastidious in nature and difficult to identify. This study was undertaken to determine the prevalence of Eikenella corrodens, Actinobacillus actinomycetemcomitans, Porphyromonas and Prevotella spp. in supragingival dental plaque collected from the right maxillary canine and carnassial teeth and the right mandibular canine tooth of dogs. In part one of the study, 30 dogs were used. E. corrodens was found in 62% of these dogs and 44% of individual plaque samples. A. actinomycetemcomitans was not detected in any of the dogs sampled. In pan two, 34 dogs were used to determine the prevalence of the black pigmented anaerobic bacilli (Porphyromonas and Prevotella spp.). Porphyromonas gingivalis was present in 68% of these dogs and 47% of individual plaque samples. Prevotella intermedia was present in 44% of the dogs and 23% of individual plaque samples. The recently described Porphyromonas canoris, Porphyromonas salivosa, Porphyromonas cangingivalis, Porphyromonas cansulci, Porphyromonas crevioricanis and Prevotella denticola species were isolated from only 9%, 6%, 3%, 3%, 3% and 3% of dogs respectively. Porphyromonas gingivicanis was not isolated from any of the animals sampled. In conclusion, black-pigmented anaerobic bacilli were isolated from 91% of the animals sampled and therefore constitute a significant risk with respect to bite wound infections. It is also suggested that the prevalence of E. corrodens in wound infections has been underestimated in previous reports because of use of inappropriate techniques for detecting this organism.

Molecular detection of feline and canine periodontal pathogens

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It is concluded that the feline oral flora is highly diverse than canine oral flora.

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Porphyromonas gingivalis, Prevotella nigrescens and Porphyromonas gulae were the dominant species in cats and dogs.

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T. forsythia, C. ochracea, and C. sputigena in cats and T. forsythia, C. ochracea, C. sputigena T. denticola and, E. corrodens, in dogs showed that the prevalence was lower than 10%. E. corrodens in cats and, P. intermedia, A. actinomycetemcomitans, and C. rectus in dogs were also isolated from the swab samples with less than 30% percentage.

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A balanced diet for cats and dogs should be provided to reduce the formation of residues in the oral flora. Daily rinsing with antiseptic solutions may also be helpful against the development of periodontal pathogens.

Periodontal disease is the most common infectious disease of cats and dogs which are strongly associated with periodontal pathogens. The primary etiologic factor in the formation of periodontal disease is microbial dental plaque accumulation on teeth. In our research, we aimed to investigate the presence of periodontal disease-related bacterial species in dental plaques of cats and dogs. Specimens collected from 50 cats and 51 dogs with periodontal disease examined in terms of periodontal pathogens by polymerase chain reaction (PCR) using primers directed to 16S rRNA and tdpA genes. Our findings indicate the presence of periodontal disease-related pathogens, especially Porphyromonas gingivalis (cats 96%, dogs 88%), Prevotella nigrescens (cats 90%, dogs 57%) and, Porphyromonas gulae (cats 70%, dogs 39%). In addition, the prevalence of Tannerella forthysia (cats 2%, dogs 4%) well-known pathogen in cats and dogs were isolated with an extremely low percentage.

Furthermore, our results suggest that the feline oral cavity microbiota has considerably more diversity than dogs. Consequently, daily oral hygiene practices may become essential for controlling the pathogenic bacteria which have clinical importance and in preventing the propagation of microorganisms in the oral cavity of cats and dogs.

Effects of immunization with natural and recombinant lysine decarboxylase on canine gingivitis development

Periodontal disease, gingival inflammation (gingivitis) and periodontal attachment loss (periodontitis), causes tooth loss and susceptibility to chronic inflammation. Professionally scaling and cleaning the teeth regularly controls the disease, but is expensive in companion animals. Eikenella corrodens is common in canine oral cavities where it is a source of lysine decarboxylase (LDC). In human dental biofilms (plaques), LDC converts lysine to cadaverine and impairs the gingival epithelial barrier to bacteria. LDC vaccination may therefore retard gingivitis development. Year-old beagle dogs provided blood samples, and had weight and clinical measurements (biofilm and gingivitis) recorded. After scaling and cleaning, two dogs were immunized subcutaneously with 0.2mg native LDC from E. corrodens and 2 sets of four dogs with 0.2mg recombinant LDC purified from Escherichia coli. A third set of 4 dogs was immunized intranasally. Rehydragel(®), Emulsigen(®), Polygen™ or Carbigen™ were used as adjuvant. Four additional pairs of dogs were sham-immunized with each adjuvant alone (controls). Immunizations were repeated twice, 3 weeks apart, and clinical measurements were obtained after another 2 weeks, when the teeth were scaled and cleaned again. Tooth brushing was then stopped and the diet was changed from hard to soft chow. Clinical measurements were repeated after 1, 2, 3, 4, 6 and 8 weeks. Compared with sham-immunized dogs, gingivitis was reduced over all 8 weeks of soft diet after subcutaneous immunization with native LDC, or after intranasal immunization with recombinant LDC in Carbigen™, but for only 6 of the 8 weeks after subcutaneous immunization with recombinant LDC in Emulsigen(®) (repeated measures ANOVA). Subcutaneous vaccination induced a strong serum IgG antibody response that decreased during the soft diet period, whereas intranasal immunization induced a weak serum IgA antibody response that did not decrease. Immunization with recombinant LDC may provide protection from gingivitis if procedures are optimized.

Topographic distribution of bacteria associated with oral malodour on the tongue

OBJECTIVE

To investigate the topographic distribution of bacterial types and loads associated with mid-morning oral malodour on the tongue surface.

DESIGN

Fifty subjects with good oral health and at least 20 natural uncrowned teeth were included. Samples were taken with sterile brushes from the dorsal anterior (DA), dorsal middle (DM), dorsal posterior (DP), dorsal posterior to the circumvallate papillae (DPCP), lateral posterior (LP) and ventral posterior (VP) tongue surfaces. Samples were cultured on appropriate media for anaerobic bacteria, aerobic bacteria, Gram-negative anaerobic bacteria, volatile sulphur compound (VSC)-producing bacteria and Streptococcus saliuarius. Malodour was assessed by trained judges on an intensity basis.

RESULTS

The counts of all bacterial groups were consistently highest at the DPCP surface. Mean VSC-producing bacterial counts (colony forming units/brush x10(5)) were 1.45, 5.67, 32.52, 88.94, 6.46 and 0.33 at DA, DM, DP, DPCP, LP and VP surfaces, respectively. Anaerobic, Gram-negative and VSC counts at DPCP surfaces increased with malodour intensity, whereas aerobic and S. saliuarius counts decreased; however these differences were not statistically significant.

CONCLUSION

It is concluded that the DPCP area consistently carries the highest load of bacteria capable of contributing to oral malodour. The study demonstrates that tongue surfaces not accessible to routine oral hygiene procedures can significantly contribute to oral malodour.

Inflammation associated with implants with different surface types

OBJECTIVES

The aim of this study was to determine the nature of the inflammatory infiltrate associated with different transmucosal implant surfaces in dogs.

METHODS

Three experimental and one control single-stage implants were randomly placed on each side of the jaw in eight dogs. The transmucosal portion of the test implants consisted of an acid-etched surface (type A), a machined surface with a circumferential groove (type C) and a surface prepared by mild anodic oxidation (type D). The control was a standard machined surface (type B). In order to determine the response to the different surfaces, plaque control was carried out twice weekly following placement of the implants for the entire period of the experiment. At 6 months, gingival biopsies and plaque samples were obtained. The area of inflammatory infiltrate and the nature of the infiltrating cell types were determined using immunohistology. Real-time polymerase chain reaction was used to identify putative periodontal pathogens.

RESULTS

Inflammatory infiltrates were associated with all implant surfaces and were commonly found subepithelially and perivascularly. T cells were the predominant infiltrating cell type in all lesions, associated with the different surfaces. In all lesions the CD4 : CD8 ratio was approximately 2 : 1. Statistical analysis showed that the type C surface (machined surface with a groove) had significantly larger inflammatory infiltrates than the type B surface (machined surface without a groove; P<0.05). No statistically significant differences were found with respect to the size of the inflammatory infiltrates or in terms of the nature of infiltrating cells. However, despite the intensive plaque control regime, plaque was present on all implant surfaces at the time of biopsy 6 months after placement. All implants had similar numbers of Tannerella forsythia, Fusobacterium nucleatum and Porphyromonas gingivalis. Actinobacillus actinomycetemcomitans, was not detected in any sample.

CONCLUSIONS

These results suggest that the development of inflammation associated with implants is independent of surface type, but is nevertheless associated with the presence of plaque. The different surfaces had no influence on the nature of the infiltrate, with T cells being the predominant cell type in all lesions. Finally, the different implant surface types seemed not to influence the peri-implant microbiota. However, the presence of the circumferential groove tended to be associated with larger infiltrates. Whether this is due to increased plaque accumulation remains to be determined.

Evaluation of bacterial nitrate reduction in the human oral cavity

It is hypothesized that the enterosalivary nitrate circulation encourages nitrate reducing bacteria to reside within the oral cavity. Nitrite production may then limit the growth of acidogenic bacteria as a result of the production of antimicrobial oxides of nitrogen, including nitric oxide. This study was carried out with 10 subjects to characterize oral nitrate reduction and identify the bacteria responsible. Nitrate reduction varied between individuals (mean 85.4 +/- 15.9 nmol nitrite min(-1) with 10 ml 1 mm KNO(3) mouth wash) and was found to be concentrated at the rear of the tongue dorsal surface. Nitrate reductase positive isolates identified, using 16S rDNA sequencing, from the tongue comprised Veillonella atypica (34%), Veillonella dispar (24%), Actinomyces odontolyticus (21%), Actinomyces naeslundii (2%), Rothia mucilaginosa (10%), Rothia dentocariosa (3%) and Staphylococcus epidermidis (5%). Nitrite production rates, using intact and permeabilized cells, of the major tongue nitrate reducers were determined in the presence of methyl and benzyl viologen. Under anaerobic conditions in the presence of nitrate, rates in decreasing order were: A. odontolyticus > R. mucilaginosa > R. dentocariosa > V. dispar > V. atypica. In conclusion, Veillonella spp. were found to be the most prevalent taxa isolated and thus may make a major contribution to nitrate reduction in the oral cavity.

Protective effect of salivary nitrate and microbial nitrate reductase activity against caries

To test the hypothesis that a combination of high salivary nitrate and high nitrate-reducing capacity are protective against dental caries, 209 children attending the Dental Institute, Barts and The London NHS Trust were examined. Salivary nitrate and nitrite levels, counts of Streptococcus mutans and Lactobacillus spp., and caries experience were recorded. Compared with control subjects, a significant reduction in caries experience was found in patients with high salivary nitrate and high nitrate-reducing ability. Production of nitrite from salivary nitrate by commensal nitrate-reducing bacteria may limit the growth of cariogenic bacteria as a result of the production of antimicrobial oxides of nitrogen, including nitric oxide.

Possible association between amniotic fluid micro-organism infection and microflora in the mouth

OBJECTIVE

To determine whether oral bacteria are found in the amniotic cavity.

DESIGN

Laboratory based analysis of clinical samples.

SETTING

Royal London Hospital, Whitechapel.

POPULATION

Forty-eight women attending for elective caesarean section.

METHODS

Dental plaque, a high vaginal swab, amniotic fluid and chorioamnion tissue were taken from women with intact membranes.

MAIN OUTCOME MEASURES

Samples were investigated using culture and microscopy for the presence of microorganisms. Amniotic fluid was analysed by polymerase chain reaction (PCR) for the presence of the ubiquitous 16S rRNA gene specific to most eubacteria. Samples were analysed using PCR genus and species specific primers directed to bacterial taxa found as part of the normal oral microflora (Streptococcus spp. and Fusobacterium nucleatum). Levels of prostaglandin E2 and cytokines were measured in amniotic fluid.

RESULTS

Amniotic fluid was positive for universal bacteria PCR, Streptococcus spp. PCR and F. nucleatum PCR in 34/48, 20/48 and 7/48 of cases, respectively. Streptococcus spp. and F. nucleatum were cultured from the dental plaque, vagina and amniotic fluid of 48/48, 14/48, 0/48 and 29/48, 6/48, 0/48 subjects, respectively. A significant association was found between detection of microbial DNA (universal and F. nucletum) and complications in previous pregnancies including miscarriage, intrauterine death, neonatal death, preterm delivery and premature rupture of membranes (P < 0.05 and P < 0.01, respectively). Prostaglandin E2 and cytokine levels, with the exception of IL-1alpha, were not significantly different between women with and without evidence of infection.

CONCLUSIONS

The results indicate that Streptococcus spp. and F. nucleatum in the amniotic fluid may have an oral origin.

Catalase-positive Eikenella corrodens and Eikenella-like isolates of human and canine origin

Ten catalase-positive isolates and one catalase-negative isolate that had been assigned to Eikenella corrodens were compared to the nomenclatural type strain regarding selected phenotypic and molecular features and chromosomal deoxyribonucleic acid (DNA) relatedness using the spectrophotometric method. Five catalase-positive human isolates were assigned to the genomic species Eikenella corrodens on the basis of high DNA relatedness levels. Three others, among them strain Chen UB 204, exhibited only moderate degrees of DNA relatedness to the type strain and with each other. Two catalase-positive isolates from dogs were closely interrelated, but yielded only low degrees of DNA binding with Eikenella corrodens and the Eikenella-like human isolates. These findings confirm that the human eikenellas comprise more than one genomic species and that the canine strains represent a distinct taxonomic entity. The differentiation of the strains investigated by conventional phenotypic features, hydrolytic enzyme reactions, and cellular carbohydrate patterns was considered.

Prevalence of Porphyromonas and Prevotella species in the dental plaque of dogs

The prevalence and populations of Porphyromonas and Prevotella species were determined in three samples of dental plaque from each of 34 healthy dogs. Porphyromonas gingivalis was present in 68 per cent of the dogs and 47 per cent of the plaque samples. The counts of P gingivalis increased with age (P < 0.1), the amount of plaque (P < 0.05) and the degree of gingivitis (P < 0.1). Prevotella intermedia was present in 44 per cent of the dogs and 23 per cent of the plaque samples. The counts of P intermedia were correlated with the amount of plaque (P < 0.05) and the degree of gingivitis (P < 0.1). Porphyromonas canoris, P salivosa, P cangingivalis, P cansulci, P crevioricanis and Prevotella denticola were isolated from only 9, 6, 3, 3, 3 and 3 per cent of the dogs, respectively. Porphyromonas gingivicanis was not isolated from any of the animals sampled. There was a highly significant (P < 0.001) correlation between the amount of plaque, the extent of gingivitis and the age of the dog.

Clinical and microbiologic evaluation of a resin modified glass ionomer cement for orthodontic bonding

This study evaluated the clinical performance of a new resin modified glass ionomer cement, Geristore (Den-Mat Corp., Santa Maria, Calif.), for the bonding of orthodontic brackets and its effect on certain caries-associated microorganisms. This cement has been shown to possess increased mechanical properties and long-term fluoride release. There were 716 brackets bonded in 40 patients (17 males and 23 females), with a split-mouth technique and a composite resin, Phase II (Reliance, Itasca, III.), as a control. Bond failures were recorded up to 1 year. Plaque scores and plaque samples were taken from the area of the bonding adhesive in 20 patients, before, at 1 week, and 5 months after the placement of brackets. The plaque samples were investigated for the presence of Streptococcus mutans and lactobacilli. The overall bond failure rate was found to be 8.9% for Geristore and 3.1% for Phase II (p < 0.05). Labially, there was no significant difference (p > 0.05) in bond failure rate: 3.8% for Geristore and 1.7% for Phase II. The proportions of S. mutans and lactobacilli in plaque taken from around Geristore cement were reduced at 1 week and 5 months, when compared with Phase II resin, and this reduction was statistically significant (p < 0.05) at 1 week. Results of this study suggest that Geristore may be of use in the labial segments, especially in caries prone patients, in whom demineralization at debond may present an esthetic and restorative problem several years after treatment.