Mitis group streptococci (MGS) were classified based on the nucleotide sequences 16S rRNA gene (16S rDNA) and comprised 13 Streptococcus species. However, 16S rDNA homogeneity among MGS was too high to discriminate between clinical strains at the species level, notably between Streptococcus mitis, Streptococcus oralis, Streptococcus pneumoniae, and Streptococcus pseudopneumoniae. The purpose of this study was to discriminate between 37 strains of MGS isolated from Korean oral cavities using phylogenetic analysis of the DNA-dependant RNA polymerase beta-subunit gene (rpoB). 16S rDNA and rpoB from clinical strains of MGS were sequenced using the dideoxy chain termination method and analyzed using MEGA version 5 software. The resulting phylogenetic data showed that the rpoB sequences could delineate clinical strains of MGS at the species level. Phylogenetic analysis of rpoB is therefore a useful approach for identifying MGS at the species level.
Base Sequence ; Discrimination (Psychology) ; DNA, Ribosomal ; DNA-Directed RNA Polymerases ; Genes, rRNA ; Streptococcus ; Streptococcus mitis ; Streptococcus oralis ; Streptococcus pneumoniae

OBJECTIVETo detect and analyze two important genes, comE and luxS, in quorum sensing signal pathway from Streptococcus oralis (S. oralis).

METHODSThe total genomic DNA of S. oralis NH521 (a clinically isolated strain) was firstly extracted. The comE and luxS genes were then amplified by polymerase chain reaction (PCR) and further sequenced. The obtained sequences were compared with related sequences in GenBank.

RESULTSTarget bands of both comE and luxS genes were detected by electrophoresis. The obtained gene sequences were similar to the corresponding sequences from another S. oralis strain (luxS, 95.0%; comE, 99.6%); however, comparing to gene sequences of another species Streptococcus mutans, comE was more divergent (12.7%) than luxS gene (74.1%).

CONCLUSIONThis study successfully amplified and sequenced comE and luxS genes from S. oralis NH521 strain. The luxS gene accumulated more mutations than comE gene did between two S. oralis strains, but comE gene is more divergent than luxS gene between two Streptococcus species.

Bacterial Proteins ; Carbon-Sulfur Lyases ; Polymerase Chain Reaction ; Quorum Sensing ; Signal Transduction ; Streptococcus mutans ; Streptococcus oralis

OBJECTIVETo investigate the influence of a broad range of environmental conditions on initial rates of hydrogen peroxide produced by Streptococcus oralis (S. oralis).

METHODSFor each rate measurement, 1 ml aliquots of 10(12) cells/L mid-logarithmic phase S. oralis in TSBY were centrifuged and respectively washed by phosphate buffer containing 0.01-10 mmol/L glucose or sucrose, phosphate buffer with 5.0-7.5 pH or Bis-Tris buffer containing 0.01-100 mmol/L Ca(2+), 0.01-100 mmol/L F(-) or 0.01-100 mmol/L HFPO(3)(-). After S. oralis was cultured in respective buffer for 10, 20 and 30 min at 37 degrees C, the concentration of hydrogen peroxide in supernatant was assayed spectrophotometrically in 96-well micro-plate by ABTS-HRP at A(405).

RESULTSSynthesis rate of hydrogen peroxide by S. oralis was 7.48 micromol/L per minute without carbohydrate, the synthesis rate of hydrogen peroxide by S. oralis increased with 0.01-10 mmol/L glucose and 0.01-10 mmol/L sucrose, but there was no statistically significant difference in synthesis rate among the carbohydrate groups. The rates of H2O2 synthesis were inhibited in the buffer at pH 5.0-6.0, compared with pH 7.0 (P < 0.05). Ca(2+) had little influence on the rate of H2O2 synthesis. IC(50) of H2O2 synthesis rates by S. oralis responded to FHPO(3)(-) and F(-) were 12.65 mmol/L and 1.90 mmol/L respectively.

CONCLUSIONSEnvironmental conditions may influence the synthesis rate of H2O2 by S. oralis.

Culture Media ; chemistry ; Glucose ; Hydrogen Peroxide ; metabolism ; Hydrogen-Ion Concentration ; Metals, Heavy ; Streptococcus oralis ; metabolism

BACKGROUND: Viridans group streptococci (VGS) are being increasingly reported as pathogens causing septicemia in neutropenic and other immunocompromised patients since 1980s. In the past, VGS were nearly uniformly susceptible to beta-lactam antimicrobial agents, aminoglycosides, tetracyclines, and macrolides. Several recent published studies, however, indicate that antimicrobial resistance may be emerging as a problem with VGS. The purpose of this study was to determine the antimicrobial susceptibility of VGS strains isolated from blood cultures in recent period. METHODS: A total of 45 consecutive strains of VGS isolated from blood cultures between May 2001 and March 2002 at Wonju Christian Hospital were tested for antimicrobial susceptibility. Identification of VGS were performed by API Strep 32(bioMerieux sa, Marcy-l'Etoile, France) commercial kit. Antimicrobial susceptibility tests were done by NCCLS recommended disk diffusion method and penicillin MICs were determined by E test. RESULTS: Among the 45 VGS strains, frequently isolated organisms were Streptococcus mitis (31.1%), Streptococcus oralis (17.8%), Streptococcus constellatus (11.1%), and Streptococcus anginosus (8.9%). Overall intermediate-and resistant rates to antimicrobial agents of VGS were as follows: penicillin; 26.7% and 8.9%, erythromycin; 4.4% and 28.9%, clindamycin 2.2% and 22.2%, and ceftriaxone; 4.4% and 6.7%, respectively. Resistant rates of Streptococcus mitis and Streptococcus oralis were as follows: penicillin; 50% vs 50%, erythromycin 43% vs 37%, clindamycin 21% vs 37%, and ceftriaxone 7% vs 25%, respectively. CONCLUSIONS: These results indicate the species-related variability of susceptibility among VGS isolated from blood in recent period. In addition to S. mitis, S. oralis also displayed high rates of resistance to penicillin, macrolides, and ceftriaxone. The difference in susceptibilities between species of VGS indicates the importance of accurate identification and the need for continuing monitoring of antimicrobial resistance.
Aminoglycosides ; Anti-Infective Agents ; Ceftriaxone ; Clindamycin ; Diffusion ; Erythromycin ; Gangwon-do ; Immunocompromised Host ; Macrolides ; Penicillin Resistance ; Penicillins ; Sepsis ; Streptococcus anginosus ; Streptococcus constellatus ; Streptococcus mitis ; Streptococcus oralis ; Tetracyclines ; Viridans Streptococci*

OBJECTIVEThe purpose of this study is to construct a pyruvate oxidase gene deficiency variant strain of Streptococcus oralis (S. oralis).

METHODSThe sopox gene, which was got using polymerase chain reaction (PCR), and the 130-basepair segment of which was cut down with endonuclease BamHI, and transferred into S. oralis (ATCC10557) by using electrotransformation. The authors obtained a variant strain of S. oralis, and then the catalase activity of the first culture and 3-4 subcultures was examined.

RESULTSThe authors obtained a pyruvate oxidase gene deficiency variant strain of S. orlis. The catalase activity examination showed that the ability of producing H2 O2 of the variant strain of S. orlis declined, whose catalase activity was between those of the positive control (ATCC10557) and the negative control (Escherichia coli, JM109). But the produced H2 O2 quantity of their subcultures was less than that of the negative control.

CONCLUSIONThe construction of the pyruvate oxidase gene deficiency variant strain of Streptococcus oralis is successful.

Cloning, Molecular ; Genes, Bacterial ; Genetic Engineering ; Genetic Variation ; Polymerase Chain Reaction ; Pyruvate Oxidase ; genetics ; Streptococcus oralis ; enzymology ; genetics

Toothbrushes play an essential role in oral hygiene. However, they can be significant in microbial transmission and can increase the risk of infection, since they can serve as a reservoir for microorganisms in healthy, oral-diseased and medically ill adults. This study was conducted to evaluate toothbrush contamination in six toothbrushes donated from four people. Two participants each supplied two toothbrushes - one used in the bathroom and one used in the workplace. The other two people each donated two toothbrushes used in the workplace. Polymerase chain reaction was used to construct a 16S rRNA clone library. Sequences of cloned DNA were compared with those from the reference organisms provided by GenBank. A total 120 clones, representing 20 clones for each toothbrush, were analyzed. They are composed of six pylum, 46 genera and 79 species. The most dominant species were Streptococcus oralis, Streptococcus parasanguinis and Haemophilus parainfluenzae. Enterobacter and Escherichia were recovered from toothbrushes used domestically. Toothbrushes used in the workplace did not contain Enterobacteria.
Adult ; Bacteria ; Clone Cells ; Databases, Nucleic Acid ; DNA ; Enterobacter ; Enterobacteriaceae ; Escherichia ; Haemophilus parainfluenzae ; Humans ; Oral Hygiene ; Polymerase Chain Reaction ; Streptococcus ; Streptococcus oralis

PURPOSE: Pneumonia is rather common and benign disease in children but its course is various. Many clinicians used the empirical antibiotics to treat pneumonia without identification of causative organism. This study was performed to find the pathogenic organism from the fluid culture by bronchoscopy with BAL (bronchoalveolar lavage) in severe pneumonia patients. METHODS: We studied 21 cases (male 15, female 6) who were admitted with severe pneumonia in the Department of Pediatrics, Sunlin Hospital from March to October in 1999. These patients had no underlying disease such as immunologic deficiency. We took laboratory tests including CBC, CRP, ESR, PB smear, mycoplasmal antibody and blood culture at admission day. We performed bronchoscopy with BAL, and wet smear and culture of that fluid. RESULTS: Organisms were cultured in nineteen cases out of 21 cases. Seven cases of Streptococcus mitis, five of Stenotrphomonas maltophilia, five cases of Streptococcus oralis, two of Moraxella species, two of Acinetobacter junii, one of Acinetobacter spesies, one Staphylococcus hominus, one alpha-h-Streptococcus, one Klebsiella pneumoniae, one Pseudomonas aeruginosa, one Enterobacter cloacae. Two organisms were cultured in nine cases. CONCLUSION: The positive rate of BALF culture was very high (90.5%). But, further studies are necessary for the patients with severe pneumonia preceded the use of antibiotics.
Acinetobacter ; Anti-Bacterial Agents ; Bronchoalveolar Lavage* ; Bronchoscopy ; Child ; Enterobacter cloacae ; Female ; Humans ; Klebsiella pneumoniae ; Moraxella ; Pediatrics ; Pneumonia* ; Pseudomonas aeruginosa ; Staphylococcus ; Streptococcus mitis ; Streptococcus oralis

Human mouth environment is known to include a variety bacteria, including Streptococcus spp., Staphylococcus spp., Actinomyces spp., Lactobacillus spp., Candida spp., Enterobacteriaceae, et al. Human oral microorganisms can cause dental caries, gingivitis, periodontitis, respiratory tract infection, and cardiovascular disease. Thus, right denture cleaning is essential to oral and general human health. The aim of this study was to evaluate the bactericidal effect of a sodium dichloroisocyanurate-based effervescent tablet (Aos Denti Germ, Aos Company, Chungbuk, Korea) against oral microorganisms. A total of 5 species Streptococcus spp. (Streptococcus anginosus, Streptococcus mitis, Streptococcus mutans, Streptococcus oralis, and Streptococcus sobrinus), Actinomyces oris, Candida albicans, and Escherichia coli were used in this study. All strains were exposed to the distilled water prepared with effervescent tablet. After the exposure, the mixture of strains and effervescent tablet was inoculated onto blood agar or MacConkey agar plate and cultured at 36℃. All strains were killed immediately on exposure to effervescent tablet. The results suggested that effervescent tablet could be used as an effective denture cleanser for dental hygiene.
Actinomyces ; Agar ; Bacteria ; Candida ; Candida albicans ; Cardiovascular Diseases ; Chungcheongbuk-do ; Dental Caries ; Denture Cleansers ; Dentures* ; Enterobacteriaceae ; Escherichia coli ; Gingivitis ; Humans ; Lactobacillus ; Mouth ; Oral Hygiene ; Periodontitis ; Respiratory Tract Infections ; Sodium ; Staphylococcus ; Streptococcus ; Streptococcus mitis ; Streptococcus mutans ; Streptococcus oralis ; Water

OBJECTIVETo elucidate the molecular structure of pyruvate oxidase gene promoter.

METHODSThe 1.30 kb fragment with promoter activity, amplified from upstream of Streptococcus oralis pyruvate oxidase gene (Sopox), was cloned into vector PBK-CMV. The positive transformed E. coli JM109 clone was selected, the recombinant plasmid was further identified with restriction mapping analysis. The positive recombinant plasmid was studied with sequence analysis.

RESULTSAfter digesting the recombinant plasmid with Hind III, 1% agarose electrophoresis showed 1.30 kb fragment, which was consistent with predicted size. Sequence analysis revealed 1,350 bp.

CONCLUSIONThe Sopox promoter region is sequenced. Further characterization of the Sopox promoter region will elucidate the molecular mechanism of H2O2 production of streptococcus oralis.

Base Sequence ; Cloning, Molecular ; Escherichia coli ; genetics ; Genes, Bacterial ; Humans ; Hydrogen Peroxide ; metabolism ; Molecular Sequence Data ; Plasmids ; genetics ; Promoter Regions, Genetic ; genetics ; Pyruvate Oxidase ; genetics ; Sequence Analysis, DNA ; Streptococcus oralis ; enzymology ; genetics

Trans-trans farnesol (tt-farnesol) is a bioactive sesquiterpene alcohol commonly found in propolis (a beehive product) and citrus fruits, which disrupts the ability of Streptococcus mutans (S. mutans) to form virulent biofilms. In this study, we investigated whether tt-farnesol affects cell-membrane function, acid production and/or acid tolerance by planktonic cells and biofilms of S. mutans UA159. Furthermore, the influence of the agent on S. mutans gene expression and ability to form biofilms in the presence of other oral bacteria (Streptococcus oralis (S. oralis) 35037 and Actinomyces naeslundii (A. naeslundii) 12104) was also examined. In general, tt-farnesol (1 mmol x L(-1)) significantly increased the membrane proton permeability and reduced glycolytic activity of S. mutans in the planktonic state and in biofilms (P < 0.05). Moreover, topical applications of 1 mmol x L(-1) tt-farnesol twice daily (1 min exposure/treatment) reduced biomass accumulation and prevented ecological shifts towards S. mutans dominance within mixed-species biofilms after introduction of 1% sucrose. S. oralis (a non-cariogenic organism) became the major species after treatments with tt-farnesol, whereas vehicle-treated biofilms contained mostly S. mutans (>90% of total bacterial population). However, the agent did not affect significantly the expression of S. mutans genes involved in acidogenicity, acid tolerance or polysaccharide synthesis in the treated biofilms. Our data indicate that tt-farnesol may affect the competitiveness of S. mutans in a mixed-species environment by primarily disrupting the membrane function and physiology of this bacterium. This naturally occurring terpenoid could be a potentially useful adjunctive agent to the current anti-biofilm/anti-caries chemotherapeutic strategies.
Actinomyces ; physiology ; Biofilms ; drug effects ; Cell Membrane Permeability ; drug effects ; Colony Count, Microbial ; Durapatite ; Farnesol ; pharmacology ; Gene Expression Regulation, Bacterial ; drug effects ; Glycolysis ; Humans ; Hydrogen-Ion Concentration ; Microbial Viability ; drug effects ; Plankton ; drug effects ; Saliva ; microbiology ; Streptococcus mutans ; drug effects ; genetics ; physiology ; Streptococcus oralis ; physiology