Draft Genome Sequence of Porphyromonas gingivalis Strain 381 Okayama (381OKJP) Stock Culture.

We report the draft genome sequence of Porphyromonas gingivalis strain 381 Okayama (381OKJP). The strain, obtained from the Socransky collection, has been used for experimentation since 1987. This sequence allows for comparisons to other sequenced 381 strains to observe acquisition of mutations and genome rearrangements in a commonly used laboratory strain.

Total bacterial counts on oral mucosa after using a commercial saliva substitute in patients undergoing hematopoietic cell transplantation.

PURPOSE: The commercial saliva substitute Oralbalance has been reported to alleviate symptoms of postradiotherapy xerostomia in head and neck cancer patients. Oralbalance may also be effective for xerostomia in patients undergoing hematopoietic cell transplantation (HCT) with high-dose chemotherapy and total-body irradiation. However, HCT patients are in a severely compromised condition, and saliva substitute must not promote infection. We reported previously that Oralbalance has antimicrobial effects against microbial species detected during HCT in vitro. This study was performed to determine the in vivo effects of Oralbalance on oral mucosal total bacterial counts in patients undergoing HCT. METHODS: A total of 18 neutropenic patients undergoing HCT were enrolled in this study. Before and after 1 week of Oralbalance use, bacterial samples were obtained from patients by wiping an area of varphi1 cm on the buccal mucosa with sterilized cotton swabs. Total bacterial counts of the obtained samples were examined by quantitative polymerase chain reaction amplification of the bacterial 16S ribosomal RNA gene. As controls, bacterial samples were also obtained from ten healthy subjects, and total bacterial counts were examined. RESULTS: No significant increase in bacterial count was observed with use of Oralbalance. None of the patients showed bacterial counts above the range found in healthy controls after using Oralbalance. CONCLUSIONS: In neutropenic patients undergoing HCT, Oralbalance did not increase the total counts of oral mucosal bacteria beyond the range found in healthy controls. Oral care using Oralbalance may alleviate the symptoms induced by hyposalivation without promoting infection.

Highly expressed genes in a rough-colony-forming phenotype of Aggregatibacter actinomycetemcomitans: implication of a mip-like gene for the invasion of host tissue.

Aggregatibacter actinomycetemcomitans, a potent pathogen of periodontitis, typically grows as a rough and adherent colony on primary isolated cultures. The colony transforms into a smooth phenotype during repeated subculture. In this study, we aimed to identify highly expressed genes in the rough-colony-forming phenotype for isolation of host-induced genes. Using a cDNA-subtractive hybridization technique, three genes, homologous to a macrophage infectivity potentiator gene (mip), peroxiredoxin gene (prx) and outer membrane protein gene (ompA), were identified. The expression levels of these genes in the rough-colony-forming phenotype were 4-10-fold higher as compared with the smooth-colony-forming phenotype. Attention was focused on the mip-like gene, and a recombinant protein and a deficient mutant were constructed. The recombinant protein reacted with sera from patients with periodontitis, suggesting the production of the Mip-like protein in periodontal lesions. Viable quantitative invasion assay demonstrated that the viable cell counts of the wild-type strain that invaded HeLa cells were more than fourfold as compared with the mip-deficient mutant. The expression of the mip-like gene, prx-like gene and ompA-like gene may be enhanced in the host, and the mip-like gene may play an important role in the infection of A. actinomycetemcomitans, especially in its invasion of the epithelium.

Distribution of Archaea in Japanese patients with periodontitis and humoral immune response to the components.

There is controversy regarding the existence of archaeal pathogens. Periodontitis is one of the human diseases in which Archaea have been suggested to have roles as pathogens. This study was performed to investigate the distribution of Archaea in Japanese patients with periodontitis and to examine the serum IgG responses to archaeal components. Subgingival plaque samples were collected from 111 periodontal pockets of 49 patients (17 with aggressive periodontitis and 32 with chronic periodontitis), and 30 subgingival plaque samples were collected from 17 healthy subjects. By PCR targeting the 16S rRNA gene, Archaea were detected in 15 plaque samples (13.5% of total samples) from 11 patients (29.4% of patients with aggressive periodontitis and 18.8% of patients with chronic periodontitis). Archaea were detected mostly (14/15) in severe diseased sites (pocket depth > or =6 mm), while no amplicons were observed in any samples from healthy controls. Sequence analysis of the PCR products revealed that the majority of Archaea in periodontal pockets were a Methanobrevibacter oralis-like phylotype. Western immunoblotting detected IgG antibodies against M. oralis in eight of the 11 sera from patients. These results suggest the potential of Archaea (M. oralis) as an antigenic pathogen of periodontitis.

Rapid and simple detection of eight major periodontal pathogens by the loop-mediated isothermal amplification method.

Loop-mediated isothermal amplification (LAMP) was applied to develop a rapid and simple detection system for eight periodontal pathogens: Aggregatibacter (Actinobacillus) actinomycetemcomitans, Campylobacter rectus, Eikenella corrodens, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Treponema denticola and Tannerella forsythia. Primers were designed from the 16S ribosomal RNA gene for each pathogen, and the LAMP amplified the targets specifically and efficiently under isothermal condition at 64 degrees C. To simplify the manipulation of LAMP examination, boiled cells and intact cells suspended in phosphate-buffered saline (PBS) were tested as templates besides extracted DNA template. The detection limits were 1-10 cells per tube using extracted DNA template. However, LAMP methods using boiled cells and intact cells required 10-100 and 100-1000 cells per tube, respectively. LAMPs for A. actinomycetemcomitans, P. gingivalis and P. intermedia were then applied to clinical plaque samples, and the method demonstrated equal or higher sensitivity compared with the conventional real-time PCR method. These findings suggest the usefulness of the LAMP method for the rapid and simple microbiological diagnosis of periodontitis, and the possibility of LAMP examination without the DNA extraction step.

Antimicrobial effects of the saliva substitute, Oralbalance, against microorganisms from oral mucosa in the hematopoietic cell transplantation period.

GOALS: The commercially available saliva substitute Oralbalance has been reported to alleviate symptoms of post-radiotherapy xerostomia in head and neck cancer patients. Oralbalance may also be effective for xerostomia in patients undergoing hematopoietic cell transplantation (HCT) with high-dose chemotherapy and total-body irradiation. However, HCT patients are severely compromised, and saliva substitute must therefore not promote infection. This study was performed to determine the effects of Oralbalance on microbial species identified during HCT. PATIENTS AND METHODS: Microbial identification of oral mucosa was performed in 28 patients undergoing HCT. The antimicrobial effects of Oralbalance against bacteria and fungi detected in the HCT period were examined in vitro. Briefly, bacteria and fungi were spread on agar plates, and 0.1g of Oralbalance gel was applied (about phi1cm). After incubation at 37 degrees C for 24h, the presence of a transparent zone of inhibition around Oralbalance was observed. MAIN RESULTS: Not only bacterial species constituting normal flora of the oral mucosa but also those not usually constituting normal flora, e.g., coagulase-negative Staphylococcus, were detected. A transparent zone was observed around Oralbalance in all bacterial species examined. No transparent zone was observed for Candida albicans, but growth was inhibited in the area where Oralbalance was applied. CONCLUSIONS: Oralbalance does not facilitate increases in microorganisms in the HCT period. Oral care with Oralbalance does not promote infection in patients undergoing HCT.

Periodontal treatment in severe aplastic anemia.

BACKGROUND: Aplastic anemia (AA) is a rare hematologic disease characterized by hypo-cellular bone marrow. The clinical features include fatigue, increased bruising, and gingival bleeding caused by anemia, leukopenia, and thrombocytopenia. A patient with AA is at high risk for infection because of leukopenia. The risk of systemic infection is especially high in AA patients with severe local infections, including periodontitis. Accordingly, periodontal treatment should include antibiotic prophylaxis to reduce the risk of systemic infection. However, treatment of periodontitis in the AA patient is significantly complicated by the bleeding disorder. We present a case report of the successful periodontal treatment of an AA patient with spontaneous gingival bleeding. METHODS: The patient was closely monitored for platelet and neutrophil counts before every treatment. The patient's platelet count was always under 10,000/microl. Therefore, it was necessary to increase platelet counts to over 25,000/microl by transfusion, after which subgingival scaling with anesthesia was performed. When the neutrophil count was less than 2,000/microl, local minocycline chemotherapy was applied to the pockets. Periodontal infection was monitored by detection of bacterial DNA and measurement of serum immunoglobulin (Ig) G titer against periodontal bacteria. RESULTS: Following the physical and chemical treatment, the gingival appearance improved dramatically and the spontaneous gingival bleeding disappeared. Moreover, the IgG titer against periodontal bacteria decreased to normal range and specific periodontal pathogens were no longer detectable in the tested pockets. CONCLUSION: We believe that the treatment strategy in the present report provides new sight into treatment planning for severely medically compromised patients.

Detection of periodontal pathogen Porphyromonas gingivalis by loop-mediated isothermal amplification method.

A method for nucleic acid amplification, loop-mediated isothermal amplification (LAMP) was employed to develop a rapid and simple detection system for periodontal pathogen, Porphyromonas gingivalis. A set of six primers was designed by targeting the 16S ribosomal RNA gene. By the detection system, target DNA was amplified and visualized on agarose gel within 30 min under isothermal condition at 64 degrees C with a detection limit of 20 cells of P. gingivalis. Without gel electrophoresis, the LAMP amplicon was directly visualized in the reaction tube by addition of SYBR Green I for a naked-eye inspection. The LAMP reaction was also assessed by white turbidity of magnesium pyrophosphate (a by-product of LAMP) in the tube. Detection limits of these naked-eye inspections were 20 cells and 200 cells, respectively. Although false-positive DNA amplification was observed from more than 10(7) cells of Porphyromonas endodontalis, no amplification was observed in other five related oral pathogens. Further, quantitative detection of P. gingivalis was accomplished by a real-time monitoring of the LAMP reaction using SYBR Green I with linearity over a range of 10(2)-10(6) cells. The real-time LAMP was then applied to clinical samples of dental plaque and demonstrated almost identical results to the conventional real-time PCR with an advantage of rapidity. These findings indicate the potential usefulness of LAMP for detecting and quantifying P. gingivalis, especially in its rapidity and simplicity.

Quantitative real-time PCR using TaqMan and SYBR Green for Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, tetQ gene and total bacteria.

Accurate quantification of bacterial species in dental plaque is needed for microbiological diagnosis of periodontal diseases. The present study was designed to assess the sensitivity, specificity and quantitativity of the real-time PCR using the GeneAmp Sequence Detection System with two fluorescence chemistries. TaqMan probe with reporter and quencher dye, and SYBR Green dye were used for sources of the fluorescence. Primers and probes were designed for Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia and total bacteria based on the nucleotide sequences of the respective 16S ribosomal RNA genes. Since spread of antibiotic resistance genes is one of the crucial problems in periodontal therapy, quantitative detection of tetQ gene, which confers resistance to tetracycline, was included in the examination. The detection of P. gingivalis, P. intermedia and A. actinomycetemcomitans was linear over a range of 10-10(7) cells (10-10(7) copies for tetQ gene), while the quantitative range for total bacteria was 10(2)-10(7) cells. Species-specific amplifications were observed for the three periodontal bacteria, and there was no significant difference between the TaqMan and SYBR Green chemistry in their specificity, quantitativity and sensitivity. The SYBR Green assay, which was simpler than TaqMan assay in its manipulations, was applied to the clinical plaque samples. The plaque samples were obtained from eight patients (eight periodontal pockets) before and 1 week after the local drug delivery of minocycline. Although the number of P. gingivalis, P. intermedia and A. actinomycetemcomitans markedly decreased after the antibiotic therapy in most cases, higher copy numbers of the tetQ gene were detectable. The real-time PCR demonstrated sufficient sensitivity, specificity and quantitativity to be a powerful tool for microbiological examination in periodontal disease, and the quantitative monitoring of antibiotic resistance gene accompanied with the antibiotic therapy should be included in the examination.

Fermentable-sugar-level-dependent regulation of leukotoxin synthesis in a variably toxic strain of Actinobacillus actinomycetemcomitans.

Actinobacillus actinomycetemcomitans, a Gram-negative periodontopathic bacterium, produces a leukotoxin belonging to the RTX family. The production of leukotoxin varies greatly among different strains of this species and under different culture conditions. A toxin-production-variable strain, 301-b, stably produces significant amounts of leukotoxin in anaerobic fructose-limited chemostat cultures, but does not do so in the presence of excess fructose. This communication describes the cloning and sequencing of the leukotoxin promoter region from 301-b, showing that this strain has a promoter region similar to that from strain 652, a moderately toxic strain. Northern blot analysis using a leukotoxin gene probe demonstrated that change in toxin production in response to the level of external fructose was due to alteration in the transcriptional level of the leukotoxin gene. Pulsing of fructose into the fructose-limited chemostat culture remarkably reduced the intracellular cAMP level from 40 pmol (mg dry wt cells)(-1) to 3.1 pmol (mg dry wt cells)(-1), which was restored when the culture was returned to fructose-limited conditions. Further, it was found that addition of external cAMP to the culture with excess fructose resulted in an apparent recovery of leukotoxin production. Taken together, these findings indicate that a cAMP-dependent mechanism, possibly a catabolite-repression-like system, may be involved in the regulation of leukotoxin production in this bacterium.