Relation of baseline microbial parameters to future periodontal attachment loss

The relationship between the level of subgingival species at baseline and subsequent attachment loss in a subject was examined. 38 subjects (14-71 years) with prior evidence of periodontal destruction were monitored 2x for pocket depth and attachment level at 6 sites per tooth at baseline and 2 months. A subject was considered to exhibit new attachment loss if 1 or more sites increased 3 mm or more in attachment level in 2 months. Subgingival plaque samples were taken at the baseline visit from the mesial aspect of each tooth (28 sites) using Gracey curettes. Samples were dispersed, diluted and plated on Trypticase soy agar supplemented with 5% sheep blood. After 7 days of anaerobic incubation, the colonies were lifted onto nylon filters, lysed and the DNA fixed to the filters. Digoxygenin-labeled DNA probes were used to enumerate 14 subgingival species. 17 of 38 subjects (44.7%) exhibited new attachment loss in 2 months. The % of the total viable count of each species was averaged for each subject. The species enumerated and the mean % of the total cultivable microbiota averaged across the active and inactive subjects were as follows; B gingivalis 2.3, 1.2; W. recta 1.3, 0.6; B. intermedius I 2.5, 2.0; B. forsythus 1.5, 1.2; A. actinomycetemcomitans serotype a 1.1, 0.8; F. nucleatum ss vincentii 1.1, 1.0; S. intermedius 2.0, 1.9; P. micros 1.5, 1.5; B. intermedius II 1.6, 1.7; A. actinomycetemcomitans serotype b 0.4, 0.6; S. sanguis I 1.8, 2.1; S. sanguis II 2.7, 3.0; V. parvula 3.9, 4.2; C. ochracea 0.9, 1.8.(ABSTRACT TRUNCATED AT 250 WORDS)

Streptococcal adherence to uncoated and saliva-coated restoratives

The adherence of Streptococcus sanguis and S. mutans to seven restoratives in the presence and absence of an artificial salivary pellicle has been investigated. The physiochemical surface characteristics of the bacteria and of the restoratives were also measured, together with the effect of salivary coating of restoratives. Zeta potential of uncoated restoratives showed a positive correlation with the number of adherent S. mutans cells and S. sanguis cells. S. sanguis showed a positive correlation with the hydrophobicity of uncoated restoratives. The surface hydrophobicity was decreased upon saliva coating, whereas the zeta potential was slightly increased. The contact angles or zeta potentials of saliva-coated restoratives were positively correlated with those of uncoated restoratives. The number of adherent cells of both S. sanguis and S. mutans to saliva-coated restoratives were decreased after the coating. Zeta potential of saliva-coated restoratives showed a positive correlation with the numbers of adherent S. mutans cells, suggesting that non-specific electrostatic interactions have an important role in the adherence of this species.

[Non-groupable streptococci: identification, sensitivity to antibiotics (Charles Nicolle Hospital in Tunis)]

50 strains of viridans streptococci isolated from human material are identified by biochemical tests (bile esculin, Cl Na 6,5%, acid production from lactose, mannitol, sorbitol, inulin, arginine, esculin and starch hydrolysis; production of levan and dextran in sucrose media) Streptococcus salivarius and Streptococcus mitis are predominant species. Susceptibility to antibiotics was studied: 70% of viridans streptococci were susceptible to all antibiotics tested, high level resistance to aminoglycoside was not present. The only resistance observed were to tetracycline, macrolides and related drugs.

Incidence of penicillin tolerance among blood culture isolates of Streptococcus sanguis, 1987-88

Laboratories that reported isolations of Streptococcus sanguis from blood cultures to the Communicable Disease Surveillance Centre (CDSC) Colindale were requested to submit strains to Bath Public Health Laboratory to allow the prevalence of penicillin tolerance within different biotypes of this species to be studied. One hundred and fifty one Streptococcus spp were received from 78 United Kingdom laboratories in one year. Strains were identified using the API 20 Strep, and minimum inhibitory concentrations (MICs) of penicillin were determined using the spiral gradient plate method. Penicillin tolerance was detected by spraying beta-lactamase over inoculated gradient plates, reincubating for 48 hours and counting the number of surviving organisms represented by colonies. There were 57 different API identification profiles encountered in the survey. Most S sanguis I/1 strains were penicillin tolerant, most S sanguis II strains were non-tolerant. The overall geometric mean MIC of penicillin was considerably lower for S sanguis I/1 than for all other biotypes. The distribution of biotypes and the geometric mean MIC of penicillin for each biotype were not significantly different for infective endocarditis strains than for all strains tested, suggesting little or no association between penicillin tolerance and the seeding of endocardium. When the reactions obtained using API 20 Strep were compared with a recent taxonomic study of viridans streptococci, 22 of 38 S sanguis I/1 strains could be reclassified as S gordonii; all these strains were penicillin tolerant. Such reclassification would allow likely penicillin tolerant strains to be predicted.

Platelet aggregation induced by uncommon serotypes of Streptococcus sanguis isolated from patients with Behçet's disease

Uncommon serotypes were tested for their ability to induce aggregation in platelet-rich plasma. Both uncommon and common serotypes induced platelet aggregation in rabbit platelet-rich plasma, but serotonin release was higher with the uncommon serotypes. Aggregation at ATP release varied between uncommon and common serotypes. With human platelet-rich plasma, only uncommon serotypes showed aggregation. Differences in serotype selectivity and the rate of aggregation were noted among platelet donors. About half of the patients with Behçet's disease and 30% of health controls showed platelet aggregation. Plasma from non-responder patients with Behçet's disease inhibited aggregation of healthy responder platelets within 20 min. Thus selective binding of uncommon serotypes of Strep. sanguis to platelets might cause the vasculitis in Behçet's disease.

Chemiluminescence of neutrophils from patients with Behçet's disease and its correlation with an increased proportion of uncommon serotypes of Streptococcus sanguis in the oral flora

Zymosan-induced chemiluminescence was investigated in whole blood and in neutrophils: in both, the peak count was frequently elevated in Behçet's disease, and was significantly higher than in healthy controls; similarly the peak time was shorter. There were more uncommon serotypes of Streptococcus sanguis in the oral flora of patients with Behçet's disease. Common serotypes were present in the flora of healthy controls, but not in patients with the disease. The percentage of Strep. sanguis in the oral flora was significantly correlated with the level of chemiluminescence response. Thus infection with uncommon serotypes of Strep. sanguis may play a role in the aetiology of Behçet's disease.

Amylase-binding as a discriminator among oral streptococci

The ability of 51 strains, belonging to Streptococcus sanguis, 'S. mitior', S. oralis and related groups, to bind salivary amylase was studied. Most strains were grouped according to their DNA-relatedness and then compared using 14 phenotypic tests. S. mitis, 'S. mitior' and three relatively new groups of strains ('CR', 'MGH' and 'Tufted mitior') bound salivary amylase, while strains of S. sanguis and S. oralis did not. The ability of strains to bind amylase or not was remarkably consistent within groups and the test proved to be reproducible, rapid and easy to perform. Combination of the amylase-binding test with 6 other conventional physiological tests allowed the construction of a dichotomous identification key which correctly identified 95% of strains for which genetic data was available. These findings suggest that the ability of organisms to bind salivary amylase could become a key test in identification schemes for certain oral streptococci.

Identification of viridans streptococci by pyrolysis-gas chromatography

An isothermal method of pyrolysis-gas chromatography (Py-GC) was used for the identification of viridans streptococci. Pyrograms from 104 reference strains were subjected to a discriminant analysis to produce classification coefficients for the identification of 74 test organisms. Five groups representing recognised species were discriminated but Streptococcus milleri strains could not be distinguished from S. sanguis. If S. milleri and S. sanguis are regarded as a single pyrogroup, only three strains out of 74 were incorrectly identified by Py-GC. A multidimensional scaling analysis of the Py-GC data produced a similar species grouping, but this statistical method was less satisfactory for pyrogram data than discriminant analysis. While Py-GC was moderately successful for the identification of viridans streptococci, this study indicated that the technique has limited use in diagnostic medical microbiology because it is time-consuming and lacks flexibility.

Serological relationships between serotype-III Streptococcus sanguis and Lancefield group-H streptococci

Certain strains of Streptococcus sanguis and group-H streptococci have been shown to have similar physiological properties and serological specificities. Serological studies revealed that serotype-III S. sanguis shared a common antigen with the so-called "British" group-H streptococci, but not with the "American" group-H streptococci. Serotype-III antigen was extracted in cold 5% trichloroacetic acid from isolated cell walls of S. sanguis ATCC 10558, and purified chromatographically. The purified serotype-III antigen consisted of neutral and amino sugars and some phosphorus, and was negatively charged. Hapten inhibition of the quantitative precipitin reaction between serotype-III antigen and antiserum indicated the strong possibility of alpha-glucosidic linkages being an immunodeterminant of the antigen.

Viridans streptococcal endocarditis: clinical, microbiological, and echocardiographic correlations

Infections caused by species within the viridans streptococci have been associated with different clinical characteristics. We studied 36 patients with viridans streptococcal endocarditis. Complications were seen in 10 (32%) of 31 patients with native valve endocarditis and four (80%) of five with prosthetic valve endocarditis and included death in two, valve replacement in six, persistent infection in three, emboli in two, and congestive heart failure in nine. Two-dimensional echocardiograms demonstrated vegetations in 26 (72%) of 36, flail mitral valves in seven, disruption of aortic valve prosthesis in one, and perivalvular abscesses in three (two Streptococcus sanguis I and one Streptococcus intermedius I). All twelve patients with native valve endocarditis who suffered complications had vegetations detected by two-dimensional echocardiography, whereas seven patients with native valve endocarditis without vegetations, as detected by two-dimensional echocardiography, had no complications (P = .03). We found no significant correlation between streptococcal species and clinical outcome. To confirm our identifications, we sent 16 identical viridans streptococcal endocarditis isolates to five institutions; only three of 16 were identified as the same species by all five institutions. We conclude that viridans streptococcal endocarditis can be associated with a virulent clinical course and that there is marked variability in species designations of individual strains by different laboratories.

High-performance liquid chromatographic analysis of bacterial fatty acid composition for chemotaxonomic characterization of oral streptococci

A high-performance liquid chromatographic method was developed to analyze the fatty acid composition of bacterial lipids. After saponification of lipids extracted from bacteria, the liberated fatty acids were labeled with a fluorescence reagent, 4-bromomethyl-7-acetoxycoumarin, followed by reversed-phase high-performance liquid chromatographic separation and fluorescence detection. All bacterial fatty acids were simultaneously separated within 30 min and sensitively determined. This method was applied to the chemotaxonomic characterization of oral streptococci. The fatty acid composition of phospholipids and total lipids distinguished Streptococcus mutans from any other species examined and showed that Streptococcus sanguis had a close taxonomic relationship with Streptococcus salivarius.

Differentiation of Streptococcus sanguis and S. mitior by whole-cell rhamnose content and possession of arginine dihydrolase

Whole-cell rhamnose concentrations were measured in 48 strains of streptococci resembling Streptococcus sanguis and S. mitior. Physiological characteristics were tested by the API-20/Strep system, and it was found that "typical" S. sanguis (arginine positive, aesculin positive) contained significant amounts of rhamnose, while "typical" S. mitior (arginine negative, aesculin negative) contained very low or undetectable amounts of rhamnose. Both groups contained dextran-positive and dextran-negative strains. Organisms that were more difficult to speciate (those giving positive results in the arginine or the aesculin test, but not in both) could also be divided into a rhamnose-positive and a rhamnose-negative group; with one exception, all of the rhamnose-positive strains gave a positive result with arginine in the API-20/Strep test. There were several discrepancies between the results of conventional tests for arginine and aesculin hydrolysis and those of the corresponding API test. The results of conventional tests for arginine hydrolysis did not correlate closely with rhamnose content, and conventional tests for aesculin hydrolysis were less sensitive than API tests. With the API-20/Strep system, S. sanguis can almost always be distinguished from S. mitior by its ability to hydrolyse arginine.

Cell surface hydrophobicity of group D and viridans streptococci isolated from patients with septicaemia

Sixty-three strains of Group D streptococci and viridans streptococci isolated from blood cultures during a two year period were typed to the species level with conventional biochemical tests and API Strep. Streptococcus faecalis was the most common species isolated followed by S. sanguis, S. mitis and S. constellatus (S. milleri). One of the two isolates of S. faecium was a contamination. The reported increasing frequency of this organism and other Group D and viridans streptococci as well as the association of S. bovis with malignant bowel disease indicate the need for full identification of streptococcal isolates from blood cultures. Pronounced surface hydrophobicity as measured with the salt aggregation test (SAT) was expressed by 59/63 (94%) of the blood culture isolates whereas strains isolated from commercial fermentation products and strains passaged several times were hydrophilic. In the presence of human serum albumin which binds to lipoteichoic acid only one strain decreased in surface hydrophobicity. The surface hydrophobicity of two strains even slightly increased indicating that lipoteichoic acid but marginally contributes to surface hydrophobicity of streptococcal cells from these species.

Genetic transformation in Streptococcus sanguis. Effects on genetic transformation by culture filtrates of Streptococcus sanguis (serogroups H and W) and streptococcus mitis (mitior) with reference to identification

Streptococcus sanguis (serogroups H and W) strains are frequently competent in genetic transformation. In a collection of 18 strains of S. sanguis isolated from blood cultures, 12 strains were spontaneously competent in transformation by streptomycin-resistant DNA, and three strains were induced to competence by the use of culture filtrates containing competence factor (CF). Culture filtrates from spontaneously competent S. sanguis strains only induced competence in transformation of strains of the same species. In addition to the three "constitutional" types of S. sanguis with regard to specificity of transformation previously reported (originally represented by the strain Challis, 13b and NCTC 7863), a possible fourth type, (represented by strain 21452) was found. Further studies are required to ascertain the role of these types. The "constitutional" types are characterized by the range of activity of their CF's. These specificities seem useful in identification of S. sanguis and its separation from S. mitis (mitior). Tests of spontaneously competent strains with culture filtrates from other competent strains showed variable effects on the transformation frequencies in different strains.

Genetic transformation in Streptococcus sanguis. Identification, surface spreading and competence of invasive strains of Streptococcus sanguis Lancefield groups H and W and other invasive viridans streptococci

Of 46 viridans streptococci isolated from cases of probably true bacteremia, 26 strains or 56% could be grouped serologically in the Lancefield system. Eight strains (17%) were identified as serogroup H (characteristic of Streptococcus sanguis), ten strains (22%) as serogroup W (a new group antigen found in S. sanguis) and eight strains (17%) as serogroup K (related to S. mitis (mitior)). The high number of serogroupable viridans streptococci was specially due to the introduction of serogroup W and indicates the importance of this serogroup in cases of bacteremia. A set of six diagnostic tests (production of hydrogen peroxide, arginine and esculin hydrolysis, polysaccharide production, Voges-Proskauer reaction, mannitol fermentation) was used for speciation of the viridans streptococci; in addition, search for spreading zones around the colonies was included in the diagnostic procedure. Spreading zones were only present in S. sanguis and occurred more frequently in group H strains than group W strains. The 46 viridans streptococci were tested in genetic transformation. The prevalence of spontaneous competence in strains isolated from the blood was high, particularly in S. sanguis serogroup H (88%) and W (50%). For serogroup H, spontaneous competence was found as frequently among invasive strains as among carrier isolates previously studied.

Serological identification of Streptococcus sanguis and Str mitior

A total of 165 strains of Streptococcus sanguis and Str mitior were selected on the basis of their biochemical reactions using established identification procedures. These strains were also classified using API Database and were then screened against five candidate grouping sera. Biochemical tests and serological identification were in general complementary, but no regular associations between biotype and serological reaction were observed.

The phylogenetic position of Streptococcus and Enterococcus

Streptococcus pyogenes, S. equinus, S. bovis, S. salivarius, S. sanguis, S. mutans, S. rattus, S. cricetus, S. lactis, S. raffinolactis and Enterococcus faecalis have been characterized by oligonucleotide cataloguing of their 16S ribosomal RNA. All the organisms form a loose but coherent group that is phylogenetically equivalent to those of lactobacilli, bacilli, the Brochothrix and Listeria group, and related taxa that constitute one of several sublines within the 'Clostridium' branch of Gram-positive eubacteria. Within the Steptococcus-Enterococcus group, organisms fall into three moderately related clusters defined by Enterococcus, the lactic acid streptococci and streptococci of the pyogenic and oral groups, respectively.

Neuraminidase activity: a biochemical marker to distinguish Streptococcus mitis from Streptococcus sanguis

Selected reference and freshly isolated strains of Streptococcus mitis (mitior) and Streptococcus sanguis were assayed for cell-associated neuraminidase activity by their ability to hydrolyze [3H-] sialyllactitol. A cell-associated neuraminidase was detected with S. mitis and S. sanguis serotype II (reclassified as S. mitis) but not with S. sanguis serotypes I and III. Neuraminidase activity of S. mitis correlated with this organism's inability to hydrolyze arginine, aesculin, and few, if any, sugars. The findings indicate that the presence of cell-associated neuraminidase activity is useful for the taxonomic classification of S. mitis.

Numerical taxonomy of Streptococcus

A numerical taxonomic study of strains of Streptococcus, together with representatives of allied genera, showed 28 reasonably distinct phenons. The major areas, with their phenons, were: (a) enterococcal species group (S. faecalis, S. faecium, 'S. avium' and a proposed new species 'S. gallinarum'); (b) paraviridans species group (S. bovis, S. equinus, S. salivarius, 'S. casseliflavus', S. mutans, S. raffinolactis and an unidentified Oral Group I); (c) lactic species group (S. lactis including S. cremoris); (d) thermophilic species group (S. thermophilus); (e) viridans species group (S. mitis, S. sanguis, a proposed new species 'S. oralis' and 'S. milleri'); (f) pyogenic species group (S. agalactiae, S. pyogenes, S. equi, 'S. equisimilis' including 'S. zooepidemicus, and a cluster of Lancefield Group B strains of human origin); (g) parapyogenic species group (S. uberis, 'S. dysgalactiae', and a cluster of strains of Lancefield Groups R, S and T). Species of Aerococcus, Gemella, Leuconostoc and Pediococcus are very closely related to the streptococci.

Purification and immunochemical characterization of Streptococcus sanguis serotype I carbohydrate antigen

The serotype-specific antigen of Streptococcus sanguis ST3 (serotype I, biotype A) was extracted, chromatographically purified, and characterized by immunological and chemical methods. The antigen was extracted from purified cell walls with hot trichloroacetic acid, followed by ion-exchange chromatography on a DEAE-Sephadex A-25 column and gel filtration through a Sephadex G-100 column. A peak fraction was obtained that gave a single precipitin band when reacted with anti-type I serum. The type I antigen was a polysaccharide composed of glucose, rhamnose, and N-acetylglucosamine in a molar ratio of 1.4:2.5:1.0. Quantitative precipitin inhibition tests with various haptenic sugars indicated that an alpha-glucosidic linkage is the immunodeterminant of the type I antigen.

Immunochemical comparison of cell-wall antigens of various viridans streptococci, including strain 2A2+3 hot from recurrent oral aphthous ulceration in man

Several studies suggest that patients with recurrent aphthous ulceration show cell-mediated and humoral immunity to antigens of Streptococcus sanguis, particularly strain 2A2+3 HOT which is said to be antigenically similar or identical to Strep. sanguis strain ATCC 10556. However, physiological classification as well as analysis of the immunologically dominant cell-wall antigens by immunoelectrophoresis and indirect immunofluorescence showed that the strain is actually a strain of Streptococcus mitis and is antigenically more like ATCC 10557 than ATCC 10556. The findings illustrate the antigenic heterogeneity of the Strep. sanguis and Strep. mitis taxons, and demonstrate the need for antigenic analysis of viridans streptococcal strains used in immunological studies of the aetiology of disease and in antiserum production. Commercial streptococcal group and antisera were also tested.

Antigenic determinant of the Lancefield group H antigen of Streptococcus sanguis

Previous studies indicated that the teichoic acid isolated from strains of Streptococcus sanguis was group specific and defined the Lancefield group H streptococci. To determine the specific antigenic determinants, the antigen was extracted from a group H streptococcus (ATCC 903) by the phenol-water method and purified by column chromatography. The isolated antigen had a glycerol/phosphate/glucose molar ratio of 1:0.9:0.3; the lipid concentration was 7.6% of its dry weight. No nucleic acids were detected, and amino acids constituted approximately 2% of the dry weight. The minimum concentration of antigen required to sensitize erythrocytes for hemagglutination with a 1:1,000 dilution of either group H antiserum or antiteichoic acid serum was 0.02 microgram/ml. Hemagglutination inhibition studies suggested that the major antigenic determinant consisted of an alpha-glucose linked to the glycerol phosphate backbone.

Isolation and immunobiological classification of Streptococcus sanguis from human tooth surfaces

A total of 113 pure cultures of Streptococcus sanguis were obtained from dental plaque samples of 64 subjects. All isolates synthesized glucan from sucrose, elaborated peroxide, and were alpha-hemolytic. Two biotypes and four serotypes were differentiated within the species. Biotype A (95 isolates) fermented salicin and inulin and hydrolyzed arginine and esculin, whereas biotype B (18 isolates) did not possess these activities. The isolates were serotyped with autoclaved extracts against whole-cell antiserum to strains ATCC 10556 or ST3 (serotype I), ATCC 10557 (serotype II), ATCC 10558 (serotype III), and ST7 (serotype IV), by the capillary precipitin test. Serotypes I, II, III, and IV were found to consist of 24, 16, 37, and 15 isolates. Type IV was demonstrated anew in this study. The remaining 21 isolates were not typed because of either multiple reactions or nonreactivity against the standardized typing sera. All isolates of serotype II belonged to biotype B, which resembles Streptococcus mitior physiologically. Five isolates representing four serotypes and an untypable strain were examined for their cariogenicity against specific-pathogen-free Sprague-Dawley rats fed high sucrose diet no. 2000. Organisms of each isolate were established in the mouths of the rats, but only three isolates induced weak caries that were restricted to pits and fissures of occlusal surfaces of the teeth.