The objective of this study was to develop PCR primers that are specific for Streptococcus sanguinis, Streptococcus parasanguinis, and Streptococcus gordonii. We designed the S. sanguinis-, S. parasanguinis-, and S. gordonii-specific primers, Ssa21-F3/Ssa21-R2, Spa17-F/Spa17-R, and Sgo41-F1/Sgo41-R1 respectively, based on the nucleotide sequences of the Ssa21, Spa17, and Sgo41 DNA probes that were screened using inverted dot blot hybridization (IDBH). The species-specificity of these primers was assessed against 43 strains of mitis group streptococci, including clinical strains of S. sanguinis, S. parasanguinis, and S. gordonii. The resulting PCR data revealed that species-specific amplicons had been obtained from all strains of the target species tested, and that none of these amplicons occurred in any other strains from other species. These results suggest that the Ssa21-F3/Ssa21-R2, Spa17-F/Spa17-R, and Sgo41-F1/Sgo41-R1 primers may be useful in detecting S. sanguinis, S. parasanguinis, and S. gordonii at the species level, respectively.
Base Sequence ; Chimera ; DNA ; DNA Probes ; Polymerase Chain Reaction ; Streptococcus ; Streptococcus gordonii

The binding of microorganisms to platelets is a critical step in the development of infective endocarditis. In Streptococcus gordonii, this binding is mediated in part by serine-rich repeat proteins, which interact directly with sialic acid residues located on GPIIb receptors in the platelet membrane. In this study, we found that S. gordonii DL1 strain binds to platelets through bridging between sialic acid residue of fibronectin and serine-rich repeat protein (Hsa). Pretreatment of fibronectin with sialidases specific for alpha(2-3)-linked sialic acids was shown to significantly inhibit binding of the DL1 strain and the binding region(BR) of Hsa protein. Similarly, pre-incubation of bacteria or BR of Hsa with alpha(2-3)-sialyl-N-acetyllactosamine blocked fibronectin binding in the DL1 strain, but not the M99 strain. Together, these data show that the alpha(2-3)-sialic acid residues of fibronectin play an important role in the binding of S. gordonii DL1 to fibronectin through interactions with the Hsa receptor. This interaction is thought to play an important role in the development of pathogenic endocarditis, and may represent an important therapeutic target for the treatment of infective endocarditis.
Bacteria ; Blood Platelets ; Endocarditis ; Etorphine ; Fibronectins* ; Membrane Glycoproteins* ; Membranes ; N-Acetylneuraminic Acid* ; Sialic Acids ; Streptococcus gordonii*

Most oral microorganisms exist as biofilms which initiate formation via the attachment of an early colonizer to host proteins on the tooth surface. Fusobacterium nucleatum act as a bridge between early and late colonizers. Dental biofilms eventually comprise dental pathogens such as Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia. To evaluate the effects of mutual interactions between oral bacteria on the growth of biofilms, periodontopathogens were co-cultured with a 0.4 microm barrier. Streptococcus gordonii inhibited the growth of F. nucleatum and periodontopathogens. However, F. nucleatum, P. gingivalis and T. denticola activated the growth of other bacteria. A co-culture system of early and late colonizers could be a useful tool to further understand bacterial interactions during the development of dental biofilm.
Bacteria ; Biofilms ; Coculture Techniques ; Colon ; Forsythia ; Fusobacterium nucleatum ; Porphyromonas gingivalis ; Proteins ; Streptococcus gordonii ; Tooth ; Treponema denticola

OBJECTIVEThis study aimed to detect the difference in the expression levels of autolysin atIS gene of Streptococcus gordonii (S. gordonii) at different growth stages and pH values, as well as to analyze the factors regulating atlS gene expression in S. gordonii.

METHODSS. gordonii wild strains (ATCC 35105) were collected at different growth stages (early exponential phase, mid-exponential phase, late exponential stage, and platform stage) and pH values (pH 7 and pH 5.5), and total RNA was extracted by using a conventional method. Fluorescence quantitative polymerase chain reaction (FQ-PCR) was used to measure the relative mRNA expression of atlS gene, with bacterial 16S rRNA as internal reference, for a comparison of the mRNA levels of atlS gene expression in S.gordonii at different growth stages and pH values.

RESULTSFQ-PCR results showed that atlS gene expression increased with gradually increasing growth stage under neutral conditions and was higher than that under acidic conditions (P < 0.05).

CONCLUSIONThe atlS gene expression in S. gordonii is influenced by growth stage and pH value factors.

PURPOSE: To report a case of streptoococcus gordonii endophthalmitis after pneumaic retinopexy in a patient with rhegmatogenous retinal detachment. CASE SUMMARY: A 40-year-old man presented with a right eye macula-on retinal detachment extending from 9 to 1 o'clock with one-clock-hour hole at 11 o'clock. After sterilizing with a Betadine solution, 0.6 cc 100% SF6 gas was injected into the vitreous through the pars plana at 11 o'clock. Two days after the injection, eyeball pain, cell and flare, and pupillary membrane developed. Under the diagnosis of endophthalmitis, vitreous tap and intravitreous vancomycin (1.0 mg/0.1 cc) and ceftazime (2.0 mg/0.1 cc) were administered. However the symptoms and signs worsened, so vitrectomy was performed, and intravitrous injections of silicone, vancomycin and ceftazime were administered. Streptococcus gordonii was identified from the excised vitreous. Visual acuity was light perception due to severe retinal necrosis. CONCLUSIONS: In cases of endophthalmitis after pneumatic retinopexy even with meticulous sterilization, a prompt operation is necessary to prevent extensive retinal damage and visual loss due to the possibility of pathogen growth other than conjunctival normal flora.
Adult ; Diagnosis ; Endophthalmitis* ; Humans ; Membranes ; Necrosis ; Povidone-Iodine ; Retinal Detachment ; Retinaldehyde ; Silicones ; Sterilization ; Streptococcus gordonii* ; Streptococcus* ; Vancomycin ; Visual Acuity ; Vitrectomy

Chlorhexidine has long been used in mouth washes for the control of dental caries, gingivitis and dental plaque. Minimal inhibitory concentration (MIC) is the lowest concentration of an antimicrobial substance to inhibit the growth of bacteria. Concentrations lower than the MIC are called sub minimal inhibitory concentrations (sub-MICs). Many studies have reported that sub-MICs of antimicrobial substances can affect the virulence of bacteria. The aim of this study was to investigate the effect of sub-MIC chlorhexidine on biofilm formation and coaggregation of oral early colonizers, such as Streptococcus gordonii, Actinomyces naeslundii and Actinomyces odontolyticus. The biofilm formation of S. gordonii, A. naeslundii and A. odontolyticus was not affected by sub-MIC chlorhexidine. However, the biofilm formation of S. mutans increased after incubation with sub-MIC chlorhexidine. In addition, cell surface hydrophobicity of S. mutans treated with sub-MIC of chlorhexidine, decreased when compared with the group not treated with chlorhexidine. However, significant differences were seen with other bacteria. Coaggregation of A. naeslundii with A. odontolyticus reduced by sub-MIC chlorhexidine, whereas the coaggreagation of A. naeslundii with S. gordonii remained unaffected. These results indicate that sub-MIC chlorhexidine could influence the binding properties, such as biofilm formation, hydrophobicity and coaggregation, in early colonizing streptococci and actinomycetes.
Actinobacteria* ; Actinomyces ; Bacteria ; Biofilms* ; Chlorhexidine* ; Colon* ; Dental Caries ; Dental Plaque ; Gingivitis ; Hydrophobic and Hydrophilic Interactions ; Mouth ; Streptococcus gordonii ; Virulence

PURPOSE: This laboratory study aimed to investigate the effect of doping an acrylic denture base resin material with nanoparticles of ZnO, CaO, and TiO₂ on biofilm formation. MATERIALS AND METHODS: Standardized specimens of a commercially available cold-curing acrylic denture base resin material were doped with 0.1, 0.2, 0.4, or 0.8 wt% commercially available ZnO, CaO, and TiO₂ nanopowder. Energy dispersive X-ray spectroscopy (EDX) was used to identify the availability of the nanoparticles on the surface of the modified specimens. Surface roughness was determined by employing a profilometric approach; biofilm formation was simulated using a monospecies Candida albicans biofilm model and a multispecies biofilm model including C. albicans, Actinomyces naeslundii, and Streptococcus gordonii. Relative viable biomass was determined after 20 hours and 44 hours using a MTT-based approach. RESULTS: No statistically significant disparities were identified among the various materials regarding surface roughness and relative viable biomass. CONCLUSION: The results indicate that doping denture base resin materials with commercially available ZnO, CaO, or TiO₂ nanopowders do not inhibit biofilm formation on their surface. Further studies might address the impact of varying particle sizes as well as increasing the fraction of nanoparticles mixed into the acrylic resin matrix.
Actinomyces ; Biofilms* ; Biomass ; Candida albicans ; Denture Bases* ; Dentures* ; Nanoparticles* ; Particle Size ; Polymethyl Methacrylate ; Spectrometry, X-Ray Emission ; Streptococcus gordonii

Minimal inhibitory concentration (MIC) is the lowest antibiotic concentration that inhibits the visible growth of bacteria. Sub-minimal inhibitory concentration (Sub-MIC) is defined as the concentration of an antimicrobial agent that does not have an effect on bacterial growth but can alter bacterial biochemistry, thus reducing bacterial virulence. Many studies have confirmed that sub-MICs of antibiotics can inhibit bacterial virulence factors. However, most studies were focused on Gram-negative bacteria, while few studies on the effect of sub-MICs of antibiotics on Gram-positive bacteria. In this study, we examined the influence of sub-MICs of doxycycline, tetracycline, penicillin and amoxicillin on biofilm formation and coaggregation of Streptococcus gordonii, Streptococcus mutans, Actinomyces naeslundii, and Actinomyces odontolyticus. In this study, incubation with sub-MIC of antibiotics had no effect on the biofilm formation of S. gordonii and A. naeslundii. However, S. mutans showed increased biofilm formation after incubation with sub-MIC amoxicillin and penicillin. Also, the biofilm formation of A. odontolyticus was increased after incubating with sub-MIC penicillin. Coaggregation of A. naeslundii with S. gordonii and A. odontolyticus was diminished by sub-MIC amoxicillin. These observations indicated that sub-MICs of antibiotics could affect variable virulence properties such as biofilm formation and coaggregation in Gram-positive oral bacteria.
Actinobacteria* ; Actinomyces ; Amoxicillin ; Anti-Bacterial Agents* ; Bacteria ; Biochemistry ; Biofilms* ; Doxycycline ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; Hydrophobic and Hydrophilic Interactions ; Penicillins ; Streptococcus gordonii ; Streptococcus mutans ; Tetracycline ; Virulence ; Virulence Factors

Antibiotics were reported to be able to alter bacterial surface properties in subinhibitory concentrations (sub-MICs). The effects of sub-MICs of certain antibiotics on a bacterial surface property such as hemagglutination, as well as on the cell morphology were studied using Streptococcus gordonii and Staphylococcus aureus. The effect of sub-M1Cs of antibiotics on the binding of these bacteria to immobilized fibrinogen were also investigated. The MICs of antibiotics were determined by culturing S. gordonii and S. aureus in media supplemented with serially diluted drug solutions, and one-half the MIC was used as the sub-MIC of the drugs, unless stated otherwise. Sub-MICs of antibiotics did not affect bacterial agglutination of erythrocytes. Microscopic observation of S. gordonii grown at sub-MIC concentration of 0.02 ug/ml of amoxicillin revealed cell enlargement of 1.6 times those grown without the drug. When grown in the sub-MIC amount of 0.08 ug/ml of cefazolin, most S. gordonii cells were enlarged and elongated into rod-shape, resulting in 3 times the size of the cells grown without the antibiotic. The data from the fibrinogen-binding experiments showed that the binding of S. gordonii to immobilized fibrinogen was increased with all the B-lactam drugs tested; the binding of S. aureus to immobilized fibrinogen, on the other hand, was decreased with the same drugs. The results show that low concentrations of certain B-lactam antibiotics are able to cause alterations in cellular morphology of S. gordonii and affect the binding of S. gordonii and S. aureus to immobilized fibrinogen.
Agglutination ; Amoxicillin ; Anti-Bacterial Agents* ; Bacteria ; Cefazolin ; Cell Enlargement ; Erythrocytes ; Fibrinogen ; Hand ; Hemagglutination ; Staphylococcus aureus* ; Staphylococcus* ; Streptococcus gordonii* ; Streptococcus* ; Surface Properties*

A positional scanning synthetic peptide combinatorial library (PS-SCL) was screened in order to identify antimicrobial peptides against the cariogenic oral bacteria, Streptococcus mutans. Activity against Streptococcus gordonii and Aggregatibacter actinomycetemcomitans was also examined. The library was comprised of six sub-libraries with the format O(1-6)XXXXX-NH2, where O represents one of 19 amino acids (excluding cysteine) and X represents equimolar mixture of these. Each sub-library was tested for antimicrobial activity against S. mutans and evaluated for antimicrobial activity against S. gordonii and A. actinomycetemcomitans. The effect of peptides was observed using transmission electron microscopy (TEM). Two semi-mixture peptides, RXXXXN-NH2 (pep-1) and WXXXXN-NH2 (pep-2), and one positioned peptide, RRRWRN-NH2 (pep-3), were identified. Pep-1 and pep-2 showed significant antimicrobial activity against Gram positive bacteria (S. mutans and S. gordonii), but not against Gram negative bacteria (A. actinomycetemcomitans). However, pep-3 showed very low antimicrobial activity against all three bacteria. Pep-3 did not form an amphiphilic alpha-helix, which is a required structure for most antimicrobial peptides. Pep-1 and pep-2 were able to disrupt the membrane of S. mutans. Small libraries of biochemically-constrained peptides can be used to generate antimicrobial peptides against S. mutans and other oral microbes. Peptides derived from such libraries may be candidate antimicrobial agents for the treatment of oral microorganisms.
Aggregatibacter actinomycetemcomitans ; Amino Acids ; Anti-Infective Agents ; Bacteria ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; Mass Screening* ; Membranes ; Microscopy, Electron, Transmission ; Peptide Library* ; Peptides ; Streptococcus gordonii ; Streptococcus mutans