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PubMed2006

Horizontal transfer of the immunoglobulin A1 protease gene (iga) from Streptococcus to Gemella haemolysans.

Bacterial IgA1 proteases share the ability to cleave human IgA1 at the hinge region. Nature has developed this trait along at least five independent evolutionary lineages. To obtain further insight into the phylogeny and function of IgA1 proteases, the nucleotide sequence of the iga gene that encodes the IgA1 protease was determined from two Streptococcus mitis strains and one Gemella haemolysans strain. Heterologous expression in Escherichia coli confirmed that the genes encode human IgA1-cleaving activity. IgA1 proteases from Streptococcus and G. haemolysans shared structural features, including a motif typical for zinc-dependent metalloproteases of clan MA(E) family M26 and an N-terminal signal sequence followed by an LPXTG cell-wall-anchor motif and two putative membrane-spanning domains. In addition, they all harboured a repeat region preceding the active site of the protease. In the streptococcal IgA1 proteases, a G5 domain, which has been suggested to bind N-acetylglucosamine, was identified. Conservation of these structures in otherwise diverse proteases suggests that they are essential to the biological function of the enzyme. The phylogenetic distribution of homologous iga genes and conservation of gene order in the iga gene region in different Streptococcus species, combined with the sequence homologies, strongly suggest that the iga gene is more ancient in Streptococcus than in G. haemolysans, and therefore that the IgA1 protease gene was transferred from Streptococcus to G. haemolysans.

Base Sequence↗
PubMed1995

Increased proportions of bacteria capable of cleaving IgA1 in the pharynx of infants with atopic disease.

Based on the observation that children with a history of atopic disease show significantly increased levels of cleaved secretory IgA in nasopharyngeal secretions, we have previously formulated the hypothesis that bacteria-induced local deficiencies of the immune barrier of the upper respiratory tract may be a contributing factor in the development and perpetuation of atopic diseases. To evaluate this hypothesis, 25 infants were subjected to clinical, bacteriologic, and immunologic examination at the age of 18 mo, 30 mo, and 5 y. The 11 infants, who showed clinical and immunologic evidence of atopic disease at the age of 18 mo, harbored significantly higher proportions of IgA1 protease-producing bacteria (median, 36%; range, 14-64%) than the 14 healthy infants (median, 5%; range, 0.4-14%). No statistically significant differences were observed at the two subsequent examinations, but healthy children showed a statistically significant increase in proportions of IgA1 protease-producing bacteria in the pharynx with increasing age. IgA1 protease-producing bacteria detected included Streptococcus mitis biovar 1, Haemophilus influenzae, Haemophilus parahaemolyticus, Streptococcus pneumoniae, and Neisseria meningitidis, of which the first mentioned species was mainly responsible for the difference observed at the 18-mo examination. Percentage proportions of IgA1 protease-producing bacteria were significantly related to passive smoking which may stimulate the premature and more pronounced pharyngeal colonization of the atopic infants with the IgA1 protease-producing variant of S. mitis biovar 1. The results of the study support the hypothesis that IgA1 protease-producing bacteria colonizing the upper respiratory tract jeopardize the local immune barrier and, thereby, may facilitate the penetration of potential allergens resulting in atopic disease.

Bacterial Infections↗
PubMed2006

Garenoxacin treatment of experimental endocarditis caused by viridans group streptococci.

The activity of garenoxacin was compared to that of levofloxacin or penicillin in a rabbit model of Streptococcus mitis group (penicillin MIC, 0.125 microg/ml) and Streptococcus sanguinis group (penicillin MIC, 0.25 microg/ml) endocarditis. Garenoxacin and levofloxacin had MICs of 0.125 and 0.5 microg/ml, respectively, for both study isolates. Rabbits with catheter-induced aortic valve endocarditis were given no treatment, penicillin at 1.2x10(6) IU/8 h intramuscularly, garenoxacin at 20 mg/kg of body weight/12 h intravenously, or levofloxacin at 40 mg/kg/12 h intravenously. For both isolates tested, garenoxacin area under the curve (AUC)/MIC and maximum concentration of drug in serum (Cmax)/MIC ratios were 368 and 91, respectively. Rabbits were sacrificed after 3 days of treatment; cardiac valve vegetations were aseptically removed and quantitatively cultured. For S. mitis group experimental endocarditis, all studied antimicrobial agents were more active than no treatment (P<0.001), whereas for S. sanguinis group endocarditis, no studied antimicrobial agents were more active than no treatment. We conclude that AUC/MIC and Cmax/MIC ratios may not predict activity of some quinolones in experimental viridans group endocarditis and that garenoxacin and levofloxacin may not be ideal choices for serious infections caused by some quinolone-susceptible viridans group streptococci.

Animals↗
PubMed2005

The salivary microbiota as a diagnostic indicator of oral cancer: a descriptive, non-randomized study of cancer-free and oral squamous cell carcinoma subjects.

BACKGROUND: The purpose of the present investigation was to determine if the salivary counts of 40 common oral bacteria in subjects with an oral squamous cell carcinoma (OSCC) lesion would differ from those found in cancer-free (OSCC-free) controls. METHODS: Unstimulated saliva samples were collected from 229 OSCC-free and 45 OSCC subjects and evaluated for their content of 40 common oral bacteria using checkerboard DNA-DNA hybridization. DNA counts per ml saliva were determined for each species, averaged across subjects in the 2 subject groups, and significance of differences between groups determined using the Mann-Whitney test and adjusted for multiple comparisons. Diagnostic sensitivity and specificity in detection of OSCC by levels of salivary organisms were computed and comparisons made separately between a non-matched group of 45 OSCC subjects and 229 controls and a group of 45 OSCC subjects and 45 controls matched by age, gender and smoking history. RESULTS: Counts of 3 of the 40 species tested, Capnocytophaga gingivalis, Prevotella melaninogenica and Streptococcus mitis, were elevated in the saliva of individuals with OSCC (p < 0.001). When tested as diagnostic markers the 3 species were found to predict 80% of cancer cases (sensitivity) while excluding 83% of controls (specificity) in the non-matched group. Diagnostic sensitivity and specificity in the matched group were 80% and 82% respectively. CONCLUSION: High salivary counts of C. gingivalis, P. melaninogenica and S. mitis may be diagnostic indicators of OSCC.

Adolescent↗
PubMed2005

Influence of fluoride, hydrogen peroxide and lactic acid on the corrosion resistance of commercially pure titanium.

Titanium is widely used in dental implantology and orthopaedics due to its excellent corrosion resistance and mechanical properties. However, it has been reported that Ti is sensitive to F(-), H(2)O(2) and lactic acid. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to investigate the corrosion resistance of CP-Ti disks after 9 days immersion in different test solutions, based on artificial saliva containing F(-) (0.5% and 2.5%), H(2)O(2) (0.1% and 10%) and/or lactic acid. Because activated macrophages and bacteria can also release locally some of these oxidative compounds, we investigated the role of these cells when plated onto titanium disks. The surface roughness (R(a)) was highly increased when titanium disks were immersed in artificial saliva containing F(-), H(2)O(2) and lactic acid. After 21 days of cell culture, R(a) was significantly increased on disks incubated with activated-J774.2 cells or Streptococcus mitis. AFM appeared to be more sensitive than SEM in evaluating the corrosion of the titanium. Chemical species, either environmental or those released by macrophages and bacteria, can provoke a marked attack of the titanium surface.

Animals↗
PubMed2005

Bacterial adhesion to silica sand as related to Gibbs energy variations.

Bacterial adhesion to silica sand was related to variations in system Gibbs energy DeltaG(adh). Two typical Gram-positive bacterial strains of Streptococcus mitis and Lactobacillus casei were used as the model bacteria in this research. Impacts of solution chemistry and goethite coating of silica sand on bacterial adhesion were also explored. S. mitis and L. casei had negative DeltaG(adh) with both uncoated and goethite-coated silica sand, demonstrating their adhesion potentials to these substrate. After goethite coating, DeltaG(adh) decreased (negatively increased) for both S. mitis and L. casei. In the presence of rhamnolipid biosurfactant, DeltaG(adh) increased (negatively decreased) in answer to the increase of the rhamnolipid biosurfactant concentration. Bacterial percentage adhesion to silica sand corresponded to DeltaG(adh). This study demonstrated that bacterial adhesion to substrate could be explained in terms of bacterial, substratum and intervening medium physicochemical surface properties, which can be independently determined based on contact angle measurements.

Bacterial Adhesion↗
PubMed2006

Commensal oral bacteria antigens prime human dendritic cells to induce Th1, Th2 or Treg differentiation.

In various immunopathologic conditions, bacterial flora induce an immune response which results in inflammatory manifestations, e.g. periapical granuloma. Dendritic cells provide the main orchestration of specific immune responses. The aim of our study was to test the capacity of distinct oral bacterial antigens (prepared from Streptococcus mitis, Propionibacterium acnes, and Bacteroides spp.) to prime human dendritic cells for stimulation of the T-lymphocyte response. To assess the T-lymphocyte response, the expression of CD25, CD69, intracellular interferon gamma (cIFN-gamma), and intracellular interleukin 4 (cIL-4) was determined. Dendritic cells were prepared from leukocyte buffy coat from healthy blood donors. Monocytes were stimulated with IL-4 and GM-CSF and dendritic cells activated with bacterial lysates. Cell suspensions contained up to 90% dendritic cells, which represented 2-12% of the initial number of mononuclear cells. Lymphocyte subsets that developed in lymphocyte cultures after 1 week of stimulation were analyzed by flow cytometry. Dendritic cells, primed with antigens of Bacteroides fragilis have shown significantly higher activation and expression of intercellular IFN-gamma by T lymphocytes compared to negative controls. The dendritic cells primed with antigens of P. acnes had no effect on T-lymphocyte activation or cytokine production; instead they induced differentiation of T lymphocytes into CD25bright cells (regulatory T cells) with a potentially inhibitory effect on immune response. Dendritic cells primed with antigens of S. mitis induced increased expression of cIL-4. We conclude that commensal oral bacteria antigens prepared from B. fragilis, S. mitis, and P. acnes prime human dendritic cells to induce Th1, Th2, and T(reg) differentiation, respectively. This may advance our understanding of immunopathologic manifestations in the oral cavity and offer new possibilities for redirecting immune responses in mucosal vaccination.

Antigens, Bacterial↗
PubMed2005

Microflora cultivable from minocycline strips placed in persisting periodontal pockets.

OBJECTIVE: The microflora that develops on minocycline strips, used as an adjunct in non-surgical periodontal therapy was studied. DESIGN AND METHODS: Minocycline (1.4 mg in polycaprolactone vehicle) and control strips were applied into all residual pockets (PD > or = 5mm, > or =2 pockets/subject) of patients with chronic periodontitis 1 month after a course of non-surgical periodontal therapy. Strips were inserted and retained for 3 days, changed to new strips for 3 more days and then removed. Strips were recovered from 14 (eight test, six control) of the 34 participants at day 0 (strip inserted, left for 30 s, removed), days 3 and 6, for (i) anaerobic culture, (ii) coliforms culture, using MacConkey agar, (iii) yeast culture, using Sabouraud's dextrose agar. RESULTS: The mean anaerobic cfu/strip (x10(5); control/test) were 2/6, 24/2, 11/2 at days 0, 3 and 6, respectively (P > 0.05). The corresponding mean proportion of Gram-negative rods and fusiforms were 27%/21%, 27%/15% and 55%/8%. The proportions of Gram-negative rods on test strips by day 6 were significantly reduced (P < 0.05). A significantly increased prevalence of Streptococcus mitis biovar 1 was found on spent test strips (control versus test; 0% versus 38%, Fisher exact test, P = 0.01). Coliform prevalence at days 0, 3 and 6 on control/test strips were 0/13%, 50%/38% and 50%/13%. Yeasts were occasionally isolated. CONCLUSIONS: The findings indicated that the minocycline strips but not the control strip supported a microbial colonisation compatible with periodontal health by day 6.

Administration, Oral↗
PubMed2005

Vegetation and bilateral congenital coronary artery fistulas.

This report describes the case of a man who presented with fever, weight loss, and Streptococcus mitis septicemia. He was found to have congenital bilateral coronary artery fistula, a rare condition. There was no evidence of vegetation on the heart valves on transthoracic or transesophageal echocardiography. Instead, transesophageal echocardiography showed vegetation within the coronary sinus near its entrance into the right atrium. Coronary angiography confirmed the presence of a left circumflex artery to coronary sinus fistula and a right coronary artery to coronary sinus fistula. To the authors' knowledge this combination of findings has never been reported before.

Adult↗
PubMed2004

Bacterial desorption in water-saturated porous media in the presence of rhamnolipid biosurfactant.

We investigated the effects of transients in elution chemistry on bacterial desorption in water-saturated porous media. Two typical Gram-positive bacterial strains of Lactobacillus casei and Streptococcus mitis were used as the model bacteria in this research. These two strains were first deposited in the porous medium, after which the medium with deposited bacteria was flushed with rhamnolipid biosurfactant solutions with a step increase in concentrations, and pulse-type bacterial releases were obtained. Bacterial desorption was quantified from bacterial breakthrough curves. It was found that bacterial retention in silica sand corresponded to bacterial interaction free energies with silica sand evaluated at the equilibrium distance, which were calculated based on independently determined bacterial, sediment and solution surface thermodynamic properties. With the increase in rhamnolipid biosurfactant concentrations, interactions between bacteria and silica sand decreased, and consequently less bacteria were retained. The decrease in interactions between bacteria and silica sand with increasing rhamnolipid biosurfactant concentrations was attributed to a decrease in the solution electron acceptor parameter of the Lewis acid/base component of surface tension, gamma3+. The increase in rhamnolipid biosurfactant concentrations favored the decrease in solution gamma3+, and consequently decreased the interactions between bacteria and silica sand.

Bacterial Physiological Phenomena↗
PubMed1992

Streptococcal and enterococcal bacteremia in patients with cancer.

Eighty-two episodes of bacteremia due to streptococci (including the genus Enterococcus) in 78 patients hospitalized at Institut Jules Bordet between 1986 and 1988 were reviewed. The incidence ranged from 5.5 to 7.6 per 1,000 admissions (16% of all bacteremias). Enterococcus faecalis, Streptococcus sanguis, and Streptococcus mitis were the most prevalent isolates, followed by Streptococcus angionosus, Streptococcus salivarius, and large colony-forming beta-hemolytic species (A, B, C, and G). Twenty-one episodes were polymicrobial. One-half of the patients had solid tumors, and one-half had hematologic malignancies. Forty-two patients were neutropenic (less than 1,000 polymorphonuclear neutrophils/microL). Only 15 episodes were acquired outside the hospital, and 11 episodes were breakthrough bacteremias. Twenty patients died within 1 month of the onset of streptococcal bacteremia. Five patients, two of whom were neutropenic, had fatal adult respiratory distress syndrome. The source of bacteremia remained undetermined in 35.4% of the episodes; the oral mucous membrane and the gastrointestinal tract were the most frequently recognized associated sites of infection. No unexpected antimicrobial resistance was observed except in two penicillin-resistant strains, one S. mitis and one E. faecium. No relation between peak or trough serum bactericidal titers and outcome could be demonstrated.

Adult↗
PubMed2002

Biofilm dispersal of Neisseria subflava and other phylogenetically diverse oral bacteria.

Polystyrene petri dishes containing liquid medium were inoculated with single-cell suspensions of a fresh clinical isolate of Neisseria subflava and were incubated under conditions of low vibration. N. subflava colonies grew firmly attached to the surface of the dish, while the broth remained clear. Growing colonies released cells into the medium, resulting in the appearance of 10(2) to 10(4) small satellite colonies attached to the surface of the dish in an area adjacent to each mature colony after 24 h. Satellite colonies grew in patterns of streamers shaped like jets and flares emanating from mature colonies and pointing toward the center of the dish. This dispersal pattern evidently resulted from the surface translocation of detached biofilm cells by buoyancy-driven convection currents that were generated due to slight temperature gradients in the medium. Streamers of satellite colonies ranged from 2 to >40 mm in length. Satellite colonies in very long streamers were relatively uniform in size regardless of their distance from the mature colony, suggesting that mature colonies released single cells or small clusters of cells into the medium and that the detachment, surface translocation, and subsequent surface reattachment of released cells were a transitory process. Incubation of N. subflava single cells in a perfused biofilm fermentor resulted in a large spike of the number of CFU in the perfusate after 9.5 h of growth, consistent with a rapid release of cells into the medium. Biofilm colonies of several other phylogenetically diverse oral bacteria, including Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, Streptococcus mitis, and a prevalent but previously uncultured oral Streptococcus sp., exhibited similar temperature-dependent dispersal patterns in broth culture. This in vitro spreading phenotype could be a useful tool for studying biofilm dispersal in these and other nonflagellated bacteria and may have physiological relevance to biofilm dispersal in the oral cavity.

Agar↗
PubMed1994

Mucin-sulphatase activity of some oral streptococci.

Mucin-sulphatase activity, measured using a 35S-[SO4(2-)]-labelled colonic mucin substrate, was detected in whole cells of Streptococci isolated from the human oral cavity. The highest levels of sulphatase activity were found in all strains of Streptococcus salivarius, Streptococcus mitis and in half of the strains of Streptococcus mutans tested. Little or no activity was detected in 9 of the 11 Streptococcus oralis strains examined, in the 4 Streptococcus constellatus strains, and in the 3 Streptococcus anginosus isolates tested. The highest enzyme levels were obtained from the two fresh Streptococcus gordonii isolates. This is the first report of such activity in oral microorganisms. Streptococcal mucin-sulphatase may contribute to the destruction of salivary mucins and mitigate their protective functions in the oral cavity, and be a determinant in the development of dental caries.

Culture Media↗
PubMed1999

Prevalence of the amylase-binding protein A gene (abpA) in oral streptococci.

Salivary amylase binds specifically to a number of oral streptococcal species. This interaction may play an important role in dental plaque formation. Recently, a 585-bp gene was cloned and sequenced from Streptococcus gordonii Challis encoding a 20.5-kDa amylase-binding protein (AbpA). The goal of this study was to determine if related genes are present in other species of oral streptococci. Biotinylated abpA was used in Southern blot analysis to screen genomic DNA from several strains representing eight species of oral streptococci. This probe hybridized with a 4.0-kb HindIII restriction fragment from all 13 strains of S. gordonii tested. The probe did not appear to bind to any restriction fragments from other species of amylase-binding oral streptococci including Streptococcus mitis (with the exception of 1 of 14 strains), Streptococcus crista (3 strains), Streptococcus anginosus (1 strain), and Streptococcus parasanguinis (1 strain), or to non-amylase-binding oral streptococci including Streptococcus sanguinis (3 strains), Streptococcus oralis (4 strains), and Streptococcus mutans (1 strain). Primers homologous to sequences within the 3' and 5' ends of abpA yielded products of 400 bp following PCR of genomic DNA from the Southern blot-positive strains. Several of these PCR products were cloned and sequenced. The levels of similarity of these cloned products to the abpA of S. gordonii Challis ranged from 91 to 96%. These studies reveal that the abpA gene appears to be specific to S. gordonii and differs from genes encoding amylase-binding proteins from other species of amylase-binding streptococci.

Amylases↗
PubMed1990

Adherence of mutans streptococci to other oral bacteria.

Adherence of mutans streptococci to strains of Actinomyces viscosus, Streptococcus sanguis, and Streptococcus mitis immobilized on a nitrocellulose membrane was measured. Strains of Streptococcus mutans, S. sobrinus, and S. rattus bound in a lactose-independent manner to a variety of the actinomyces and streptococci. Most of these reactions could proceed in the presence of whole saliva although adherence of S. rattus BHT to the streptococci was inhibited by salivary molecules. In contrast, adherence of S. mutans 10449 and KPSK2 to A. viscosus, S. sanguis, and S. mitis was enhanced by salivary molecules. S. mutans KPSK2, S. sobrinus OMZ 176, and S. rattus FA-1 binding to A. viscosus NC3 and S. sanguis G9B exhibited saturation kinetics. Adherence to A. viscosus NC3 was of a higher avidity than adherence to S. sanguis G9B. Attachment of S. mutans KPSK2 to S. sanguis G9B and of S. mutans OMZ 176 to A. viscosus NC3 and S. sanguis G9B was inhibited by heat treatment of the mutans streptococci. Attachment of S. mutans KPSK2 to A. viscosus NC3 and of S. rattus FA-1 to A. viscosus NC3 and S. sanguis G9B was unaffected by heat. These observations suggest that the mutans streptococci can adhere to a variety of early plaque bacteria by several distinct mechanisms. Such interactions may be important in the colonization of tooth surfaces by the mutans streptococci.

Actinomyces↗
PubMed1982

Adsorption of lysozyme from human whole saliva by Streptococcus sanguis 903 and other oral microorganisms.

Several strains of Streptococcus sanguis, Streptococcus mutans, Streptococcus mitis, Actinomyces viscosus, and Actinomyces naeslundii plus fresh isolates of Streptococcus salivarius were surveyed for their abilities to deplete lysozyme from human-whole-saliva supernatant. Bacteria were incubated in saliva for 60 min at 37 degrees C and then removed by centrifugation, and the recovered supernatant solutions were assayed for lysozyme activity by using whole cells of Micrococcus lysodeikticus as the substrate. Mean lysozyme depletions by bacterial strains varied over a wide (eightfold) range. The greatest mean depletion of lysozyme (60 to 70%) was observed with S. sanguis (biotype I), serotype b of S. mutans, and the fresh S. salivarius isolates. The lowest mean depletion was noted with S. mitis (15%) and biotype II S. sanguis (ca. 30%). The remaining species and strains exhibited an intermediate degree of depletion. In studies with S. sanguis 903, lysozyme was depleted by normal or heated (90 degrees C, 30 min) bacteria and could be recovered from the organism. Furthermore, under appropriate conditions, lysozyme depletion by cells at 0 and 37 degrees C was very similar. On the basis of these observations, we concluded that depletion was due to the adsorption of lysozyme by the organism. With S. sanguis 903, lysozyme adsorption depended on the concentration of bacteria, time of incubation, and the ionic strength of the medium. The extent of adsorption, however, was independent of pH's of 3.9 to 8.3. When a low concentration of S. sanguis 903 was used, lysozyme adsorption reached saturation (4 mug of adsorbed lysozyme per 10(7) cells) at 20 mug of lysozyme added per ml. Salivary lysozyme adsorption by several other oral microorganisms (A. viscosus WVU 626 and WVU 627, S. sanguis 73x11, S. mutans BHT, and S. salivarius NG) was similar to that of S. sanguis 903 in sensitivity to ionic strength. Lysozyme adsorption by S. sanguis 903 from either a buffer solution or a saliva supernatant was more sensitive to ionic strength at 0 than at 37 degrees C. On the basis of results from experiments in saliva versus buffer, we concluded that saliva had no major effect on the extent of lysozyme adsorption by S. sanguis 903 other than providing a source of ionic strength. A comparison of pH and ionic strength effects on lysozyme adsorption by S. sanguis 903 with literature reports of lysozyme lysis of whole cells and hydrolysis of cell walls, peptidoglycan, and (GlcNAc)(4) suggested that adsorption by S. sanguis 903 was more dependent on electrostatic interactions than was lysozyme catalysis. The possibility is discussed that anionic bacterial surface components mediate lysozyme adsorption and temper the potential effects of lysozyme on the microorganisms.

Actinomyces↗
PubMed1993

Oral streptococcal colonization of infants.

The objective of this study was to determine the prevalence and proportions of different streptococcal species among the streptococcal flora during infancy. A total of 60 oral samples were collected by oral swabbing of the buccal mucosa and alveolar ridges of 18 infants before tooth eruption and from buccal and lingual surfaces of teeth after tooth eruption. A total of 549 isolates on mitis salivarius agar were speciated, principally by recently revised biochemical criteria of Kilian et al. Streptococcus mitis biovar 1 predominated, both in prevalence (89%) and proportion of oral streptococci recovered in each sample (median = 87% of streptococcal flora). Streptococcus salivarius was also prevalent (94%) but generally represented a small percentage of the total streptococcal flora (median = 3%). Streptococcus oralis and Streptococcus anginosus strains were detected in approximately one third of predentate and dentate infants in the first year of life. Streptococcus sanguis strains were not detected before tooth eruption, but could be detected in 7/14 of the infants with teeth. Thus, S. mitis constitutes the major component of the initially colonizing streptococcal microbiota of the young infant.

Alveolar Process↗
PubMed1980

Role of bacterial interactions in the colonization of oral surfaces of Actinomyces viscosus.

The effects of several microbial residents of human oral cavities on the attachment of Actinomyces viscosus T14V to tooth surfaces were assessed by using the saliva-coated hydroxyapatite (sHA) in vitro system. Attachment to sHA by A. viscosus T14V was not inhibited in the presence of Streptococcus mutans GS5, either in the presence or absence of sucrose. Precoating sHA beads with S. mutans in the presence of sucrose also did not retard strain T14V attachment. However, the presence of Streptococcus sanguis M5 during strain T14V attachment markedly inhibited the interaction of A. viscosus T14V with sHA, whereas another S. sanguis strain, strain G9B, produced relatively weak inhibition. The inhibitory effect of S. sanguis M5 appeared to result from the direct interaction of this organism with A. viscosus T14V. Conversely, the presence of strain T14V markedly increased the attachment of S. sanguis M5 to sHA while partially inhibiting the attachment of S. sanguis G9B. Moreover, sHA beads precoated with A. viscosus T14V bound much higher levels of S. sanguis M5 relative to uncoated sHA, whereas S. sanguis G9B attachment was only weakly inhibited. It was also observed that sHA beads precoated with either S. sanguis M5 or G9B inhibited subsequent attachment by strain T14V. These results suggest the possibility that the attachment sites for both S. sanguis strains partially overlap those for A. viscosus T14V. Streptococcus mitis weakly inhibited attachment of strain T14V to sHA, and both Streptococcus salivarius and Lactobacillus casei had little effect on attachment. In addition, both a radioisotope attachment assay and fluorescent microscopy demonstrated no significant attachment of A. viscosus T14V to human epithelial cells.

Actinomyces↗