Distribution of Streptococcus mutans strains with collagen-binding proteins in the oral cavity of IgA nephropathy patients

BACKGROUND

IgA nephropathy (IgAN) is the most common primary chronic glomerulonephritis; however, its precise initiating pathogenesis remains unclear. Streptococcus mutans is a major pathogen of human dental caries. S. mutans strains with the cnm gene encoding Cnm, a collagen-binding protein, have been reported to contribute to the development of systemic diseases. However, the contribution of S. mutans with Cnm in the development of IgAN has not been reported. The aim of this study was to investigate the prevalence of cnm-positive S. mutans in IgAN patients and clarify the effects of cnm-positive S. mutans on the histological pathology of IgAN.

METHODS

We identified the cnm gene in S. mutans isolated in saliva specimens, which were collected from IgAN patients (n = 53) and control subjects (n = 50). We evaluated the collagen-binding properties of S. mutans in IgAN patients and controls. The clinical parameters and histological scores were also assessed in IgAN patients.

RESULTS

The rates of S. mutans isolation in IgAN and control groups were 84.0 and 84.9 %, respectively, not significantly dfferent. cnm-positive strains were significantly more prevalent in the IgAN group than in controls (32.1 vs. 14.0 %, p < 0.05). With regard to collagen-binding assays, the binding rates of cnm-positive strains were significantly higher in the IgAN group than in controls (96.6 vs. 30.0, p < 0.05). In addition, the segmental glomerulosclerosis scores were significantly higher in cnm-positive patients with IgAN than in cnm-negative patients with IgAN (0.94 vs. 0.57, p < 0.05).

CONCLUSION

cnm-positive S. mutans strains are potentially associated with the pathogenesis of IgAN.

Detection of Helicobacter pylori DNA in inflamed dental pulp specimens from Japanese children and adolescents

The oral cavity has been implicated as a source of Helicobacter pylori infection in childhood. Various PCR methods have been used to detect H. pylori DNA in oral specimens with various detection rates reported. Such disparity in detection rates complicates the estimation of the true infection rate of H. pylori in the oral cavity. In the present study, we constructed a novel PCR system for H. pylori detection and used it to analyse oral specimens. Firstly, the nucleotide alignments of genes commonly used for H. pylori detection were compared using the complete genome information for 48 strains registered in the GenBank database. Candidate primer sets with an estimated amplification size of approximately 300-400 bp were selected, and the specificity and sensitivity of the detection system using each primer set were evaluated. Five sets of primers targeting ureA were considered appropriate, of which a single primer set was chosen for inclusion in the PCR system. The sensitivity of the system was considered appropriate and its detection limit established as one to ten cells per reaction. The novel PCR system was used to examine H. pylori distribution in oral specimens (40 inflamed pulp tissues, 40 saliva samples) collected from Japanese children, adolescents and young adults. PCR analysis revealed that the detection rate of H. pylori in inflamed pulp was 15 %, whereas no positive reaction was found in any of the saliva specimens. Taken together, our novel PCR system was found to be reliable for detecting H. pylori. The results obtained showed that H. pylori was detected in inflamed pulp but not saliva specimens, indicating that an infected root canal may be a reservoir for H. pylori.

Identification and functional analysis of an ammonium transporter in Streptococcus mutans

Streptococcus mutans, a Gram-positive bacterium, is considered to be a major etiologic agent of human dental caries and reported to form biofilms known as dental plaque on tooth surfaces. This organism is also known to possess a large number of transport proteins in the cell membrane for export and import of molecules. Nitrogen is an essential nutrient for Gram-positive bacteria, though alternative sources such as ammonium can also be utilized. In order to obtain nitrogen for macromolecular synthesis, nitrogen-containing compounds must be transported into the cell. However, the ammonium transporter in S. mutans remains to be characterized. The present study focused on characterizing the ammonium transporter gene of S. mutans and its operon, while related regulatory genes were also analyzed. The SMU.1658 gene corresponding to nrgA in S. mutans is homologous to the ammonium transporter gene in Bacillus subtilis and SMU.1657, located upstream of the nrgA gene and predicted to be glnB, is a member of the PII protein family. Using a nrgA-deficient mutant strain (NRGD), we examined bacterial growth in the presence of ammonium, calcium chloride, and manganese sulfate. Fluorescent efflux assays were also performed to reveal export molecules associated with the ammonium transporter. The growth rate of NRGD was lower, while its fluorescent intensity was much higher as compared to the parental strain. In addition, confocal laser scanning microscopy revealed that the structure of biofilms formed by NRGD was drastically different than that of the parental strain. Furthermore, transcriptional analysis showed that the nrgA gene was co-transcribed with the glnB gene. These results suggest that the nrgA gene in S. mutans is essential for export of molecules and biofilm formation.

Venous reddening as a possible sign of hyperperfusion after superficial temporal artery-middle cerebral artery anastomosis for moyamoya disease: case report

Here we report a case of moyamoya disease in which cortical veins reddened after superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis, following postoperative hyperperfusion. A 37-year-old man with moyamoya disease suffered cerebral infarction in his right hemisphere. Single photon emission computed tomography (SPECT) showed impaired cerebral blood flow (CBF) in both cerebral hemispheres. The patient underwent STA-MCA anastomosis in the right cerebral hemisphere. During operation, soon after declamping the STA, cortical veins near the anastomosis site changed its color from blue to red. This change was repeatable by clamping and declamping of the STA. Postoperative SPECT and computed tomography (CT) demonstrated increased CBF and subarachnoid hemorrhage at the anastomosis site, suggesting the occurrence of postoperative hyperperfusion. By strictly controlling the patient's blood pressure, the syndrome resolved 1 week after the operation. We propose that the venous reddening after STA-MCA anastomosis may be a sign of postoperative hyperperfusion.

Correlation of age with distribution of periodontitis-related bacteria in Japanese dogs

We analyzed the distribution of 11 periodontitis-related bacterial species in dental plaque collected from 176 Japanese dogs divided into young (less than 2 years of age), middle-aged (2-7 years of age) and elderly (more than 8 years of age) groups using a polymerase chain reaction method. Clinical examination revealed that no dogs in the young group were affected by periodontitis, whereas the rates for gingivitis and periodontitis were high in the middle-aged and elderly groups. In addition, the total numbers of bacterial species in the middle-aged and elderly groups were significantly greater than in the young group. Our findings suggest that age is an important factor associated with the distribution of periodontitis-related bacteria and periodontal conditions in dogs.

Aggravation of inflammatory bowel diseases by oral streptococci

OBJECTIVES

Streptococcus mutans can aggravate colitis in mice. We evaluated the virulence of colitis using type strains as well as blood isolates of several oral streptococcal species.

MATERIALS AND METHODS

We investigated the susceptibility of blood isolates of several oral streptococci to phagocytosis, adhesion to and invasion of hepatic cells and interferon-γ secretion. A mouse model of dextran sodium sulphate-induced colitis was used to evaluate bacterial aggravation of colitis. In addition, interferon-γ antibody was administered to mice with prominent aggravation of colitis.

RESULTS

In vitro analyses showed that Streptococcus sanguinis ATCC 10556 was a possible virulent strain among type strains of several oral streptococci, and that analysis of blood isolates of S. sanguinis TW289 revealed a potential virulent strain. Intravenous administration of ATCC 10556 and TW289 caused prominent aggravation of dextran sodium sulphate-induced colitis, and histopathological examinations showed that interferon-γ secretion due to infection of hepatic cells caused colitis aggravation. Administration of interferon-γ antibody suppressed TW289-induced colitis.

CONCLUSION

These results suggest that some virulent oral streptococcal strains are associated with the aggravation of colitis induced by enhanced secretion of interferon-γ when they invade the bloodstream.

Multilocus sequence typing of Streptococcus mutans strains with the cbm gene encoding a novel collagen-binding protein

OBJECTIVE

Streptococcus mutans, an oral pathogen associated with infective endocarditis (IE), possesses two genes encoding collagen-binding proteins, namely cnm and cbm. In this study, we used multilocus sequence typing (MLST) of S. mutans with the cbm gene.

DESIGN

Forty-five S. mutans strains including 15 strains with the cnm gene, 15 strains with the cbm gene, and 15 strains without these two genes were analysed by MLST. In addition, the collagen-binding properties as well as the abilities to adhere to and invade human umbilical vein endothelial cells (HUVEC) were also evaluated for all strains.

RESULTS

In the groups of cnm-positive and cbm-positive strains, all properties, including collagen binding, adhesion, and invasion were significantly greater than those of the cnm-cbm-negative group. Moreover, MLST revealed three clonal complexes of S. mutans possessing the cbm gene. These three clones showed no close relatedness with clones of strains containing the cnm gene. Among three clones harbouring the cbm gene, two clones belong to serotype k, and appeared to be associated with the pathogenesis of IE due to their strong collagen binding and relatively enhanced abilities to adhere to and invade endothelial cells. However, such properties were relatively weak in the other non-serotype k clone possessing the cbm gene.

CONCLUSIONS

MLST indicated a difference in evolution between S. mutans strains with the cbm gene and those with the cnm gene. In addition, this technique also suggested the importance of cbm-positive S. mutans clones relative to the pathogenesis of IE.

The effect on the bones of condensed phosphate when used as food additives: Its Importance in Relation to Preventive Medicine

Based on the fact that chemical products such as binding agents are produced by mixing three kinds of phosphates with different ratios, we mixed metaphosphate, polyphosphate and pyrophosphate. Each was made to Na-phosphate, K-phosphate, and Ca-phosphate and each was mixed with commercial feeds so that the content of P would be approximately 0.1, 0.15, 0.3, 0.4, 0.6 and 1.0%. The prepared pellets were given to ICR, CF # 1 and AKR strains of mice at 29 days of age for 680 days and observations were made through this experimental period at different stages. The observations were also carried out on the mice administered with the experimental feeds for 1.5 months from 9 to 10.5 months of age. The observations were compared with those of the control group at all times. As a result, plasma 1 α, 25 (OH)(2) D(3) and P levels were always significantly higher in the phosphate administered groups relative to the control. Urine P and Fe increased while urine Ca decreased in the phosphate-treated groups.The effect of phosphates on the bones was studied taking soft X-ray pictures of hind legs and applying microdensitometry to them. Through these observations we recognized thinning of the cortex of bones, reduction of marrow trabecules and development of osteophyte. Histological observations disclosed that changes in knee joint tissues were apparent; that is, a decrease in or an irregular loss of the number of cells in superficial, intermediate, and radial strata of the joint cartilage, proliferation of subchondral bone, and the development of osteophytes were noted. As for muscles, diameters of musclar fibers became smaller; in particular, type II fibers showed greater shrinkage. Regarding kidneys, swelling and atrophy of glomerular capillaries, proliferation of mesangial cells, nephroselerosis, swelling, thinning, and loss of tubular epithelium, interstitial tissue inflammation, development of cylindruria, and deposition of calcium were observed. All these changes seem to be a particularly advanced aspect of the changes which are more pronounced with increasing dose and age.These changes were found even in the group administered with the feed containing 0.1% phosphorus, and, these changes were dependent on the concentration level of P. It was observed that administration to older subjects for a short term (1.5 months) produced effects stronger than those to younger subjects administered for a long term (10.5 months).The effects of condensed Ca-phosphate on bones were similar to those of condensed Na- and K-phosphates, and, hence, it was supposed that these effects were caused by phosphate radicals.

Potential involvement of collagen-binding proteins of Streptococcus mutans in infective endocarditis

OBJECTIVE

Streptococcus mutans, a major pathogen of dental caries, is considered to be one of the causative agents of infective endocarditis (IE). Two types of cell surface collagen-binding proteins, Cnm and Cbm, have been identified in the organism. The aim of the present study was to analyze these proteins as possible etiologic factors for IE.

MATERIALS AND METHODS

The binding activities of S. mutans strains to collagen types I, III, and IV were analyzed relative to the presence of Cnm and Cbm, as were their adhesion and invasion properties with human umbilical vein endothelial cells (HUVEC). In addition, distributions of the genes encoding Cnm and Cbm in S. mutans-positive heart valve specimens extirpated from IE and non-IE patients were analyzed by PCR.

RESULTS

Most of the Cbm-positive strains showed higher levels of binding to type I collagen as well as higher rates of adhesion and invasion with HUVEC as compared to the Cnm-positive strains. Furthermore, the gene encoding Cbm was detected significantly more frequently in heart valve specimens from IE patients than from non-IE patients.

CONCLUSIONS

These results suggest that the collagen-binding protein Cbm of S. mutans may be one of the potential important factor associated with the pathogenesis of IE.

Surface Andreev bound states of superfluid 3He and Majorana fermions

Superfluid (3)He is an intensively investigated and well characterized p-wave superfluid. In the bulk Balian-Werthamer state, which is commonly called the (3)He B phase, the superfluid gap is opened isotropically but near a flat boundary such as a wall of a container it can harbor interesting quasi-particle states inside the gap. These states are called surface Andreev bound states, and have not been experimentally explored in detail. Transverse acoustic impedance measurement has revealed their existence and provided spectroscopic details of the dispersion of the bound states. Recent theoretical arguments claim that the surface Andreev bound states of the superfluid (3)He B phase can be recognized as the edge states of the topological superfluid and be regarded as a Majorana fermion, a fancy particle which has not been confirmed in elementary particle physics. In this review, we present up-to-date knowledge on the surface Andreev bound states of the (3)He B phase revealed by acoustic spectroscopy and the possible realization of a Majorana fermion, along with related studies on this topic.

Infection of specific strains of Streptococcus mutans, oral bacteria, confers a risk of ulcerative colitis

Although oral bacteria-associated systemic diseases have been reported, association between Streptococcus mutans, pathogen of dental caries, and ulcerative colitis (UC) has not been reported. We investigated the effect of various S. mutans strains on dextran sodium sulfate (DSS)-induced mouse colitis. Administration of TW295, the specific strain of S. mutans, caused aggravation of colitis; the standard strain, MT8148 did not. Localization of TW295 in hepatocytes in liver was observed. Increased expression of interferon-γ in liver was also noted, indicating that the liver is target organ for the specific strain of S. mutans-mediated aggravation of colitis. The detection frequency of the specific strains in UC patients was significantly higher than in healthy subjects. Administration of the specific strains of S. mutans isolated from patients caused aggravation of colitis. Infection with highly-virulent specific types of S. mutans might be a potential risk factor in the aggravation of UC.

Distribution of periodontopathic bacterial species in dogs and their owners

OBJECTIVE

Presently, a large number of individuals consider their companion animals as family members and have close contact with them in daily life. The purpose of the present study was to analyze the distribution of periodontopathic bacterial species in oral specimens taken from dogs and their owners.

DESIGN

Dental plaque specimens were collected from 66 dogs and 81 members of 64 families who came to an animal clinic or dog training school in Okayama, Japan, in 2011. Bacterial DNA was extracted from each specimen and PCR analyses using primers specific for 11 periodontopathic species, Porphyromonas gingivalis, Porphyromonas gulae, Treponema denticola, Tannerella forsythia, Capnocytophaga ochracea, Capnocytophaga sputigena, Prevotella intermedia, Prevotella nigrescens, Aggregatibacter actinomycetemcomitans, Campylobacter rectus, and Eikenella corrodens were performed.

RESULTS

P. gulae (71.2%), T. forsythia (77.3%), and C. rectus (66.7%) were frequently found in the dogs, whereas the detection rates of those species in humans were less frequent at 16.0%, 30.9%, and 21.0%, respectively. P. gulae was identified in 13 human subjects and each of their dogs was also positive for the species. Furthermore, E. corrodens and T. denticola in specimens obtained from dogs were correlated with their presence in specimens from owners who had close contact with them.

CONCLUSIONS

These results suggest that several periodontopathic species could be transmitted between humans and their companion dogs, though the distribution of periodontopathic species in both is generally different.

Diversity of fimbrillin among Porphyromonas gulae clinical isolates from Japanese dogs

Porphyromonas gulae, a gram-negative black-pigmented anaerobe, is a pathogen for periodontitis in dogs. An approximately 41-kDa fimbrial subunit protein (FimA) encoded by fimA is regarded as associated with periodontitis. In the present study, the fimA genes of 17 P. gulae strains were sequenced, and classified into two major types. The generation of phylogenetic trees based on the deduced amino acid sequence of FimA of P. gulae strains along with sequences from several strains of Porphyromonas gingivalis, a major cause of human periodontitis, revealed that the two types of FimA (types A and B) of P. gulae were similar to type I FimA and types II and III FimA of P. gingivalis, respectively. A PCR system for classification was established based on differences in the nucleotide sequences of the fimA genes. Analysis of 115 P. gulae-positive oral swab specimens from dogs revealed that 42.6%, 22.6%, and 26.1% of them contained type A, type B, and both type A and B fimA genes, respectively. Experiments with a mouse abscess model demonstrated that the strains with type B fimA caused significantly greater systemic inflammation than those with type A. These results suggest that the FimA proteins of P. gulae are diverse with two major types and that strains with type B fimA could be more virulent.

Involvement of a periodontal pathogen, Porphyromonas gingivalis on the pathogenesis of non-alcoholic fatty liver disease

Background

Non-alcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome that is closely associated with multiple factors such as obesity, hyperlipidemia and type 2 diabetes mellitus. However, other risk factors for the development of NAFLD are unclear. With the association between periodontal disease and the development of systemic diseases receiving increasing attention recently, we conducted this study to investigate the relationship between NAFLD and infection with Porphyromonas gingivalis (P. gingivalis), a major causative agent of periodontitis.

Methods

The detection frequencies of periodontal bacteria in oral samples collected from 150 biopsy-proven NAFLD patients (102 with non-alcoholic steatohepatitis (NASH) and 48 with non-alcoholic fatty liver (NAFL) patients) and 60 non-NAFLD control subjects were determined. Detection of P. gingivalis and other periodontopathic bacteria were detected by PCR assay. In addition, effect of P. gingivalis-infection on mouse NAFLD model was investigated. To clarify the exact contribution of P. gingivalis-induced periodontitis, non-surgical periodontal treatments were also undertaken for 3 months in 10 NAFLD patients with periodontitis.

Results

The detection frequency of P. gingivalis in NAFLD patients was significantly higher than that in the non-NAFLD control subjects (46.7% vs. 21.7%, odds ratio: 3.16). In addition, the detection frequency of P. gingivalis in NASH patients was markedly higher than that in the non-NAFLD subjects (52.0%, odds ratio: 3.91). Most of the P. gingivalis fimbria detected in the NAFLD patients was of invasive genotypes, especially type II (50.0%). Infection of type II P. gingivalis on NAFLD model of mice accelerated the NAFLD progression. The non-surgical periodontal treatments on NAFLD patients carried out for 3 months ameliorated the liver function parameters, such as the serum levels of AST and ALT.

Conclusions

Infection with high-virulence P. gingivalis might be an additional risk factor for the development/progression of NAFLD/NASH.