Restriction endonuclease-fragment polymorphisms of oral viridans streptococci, compared by conventional and field-inversion gel electrophoresis.

Oral streptococci formerly classified as Streptococcus sanguis or Streptococcus mitis have recently been divided into four species. Two additional species have also been proposed for this group. Each species is genetically distinct, but they have many traits in common, which makes it difficult for clinical isolates to be identified by phenotypic tests. Genotypic comparison may provide an alternative approach. This study used DNA fingerprint analysis for comparison of genotypes of 21 reference strains--classified as Streptococcus gordonii, Streptococcus sanguis, Streptococcus oralis, "Streptococcus parasanguis", or "Streptococcus crista" in previous DNA hybridization studies--and 17 clinical and laboratory strains placed in those groups on the basis of phenotypic tests. HinDIII and PvuII digests were run in conventional horizontal agarose gels. SfiI digests of reference strains and two laboratory strains were run in field-inversion gels. Fingerprint patterns were compared by visual examination, cluster analysis of densitometric traces, and lane-matching software. Only two "S. crista" strains and two parent mutant lineages showed fingerprint patterns that were identical by visual examination. Fingerprint patterns of all other strains were unique. Cluster analysis results could not be considered valid, since replicate lanes in different gels were not grouped together. HinDIII and PvuII digests contained too many bands for correct matching by lane-matching software. SfiI digests were correctly matched by computer, with the same results as visual examination. Results indicate that the diversity of strains within these streptococcal species was too great to permit species identification by DNA fingerprint patterns. This genotypic diversity suggests that isolates from unrelated hosts may have been separate for long periods of time.(ABSTRACT TRUNCATED AT 250 WORDS)

Antimicrobial proteins in human unstimulated whole saliva in relation to each other, and to measures of health status, dental plaque accumulation and composition.

Saliva antimicrobial proteins may interact in a common system to influence the oral ecology. Clinical studies of antimicrobial protein action thus may require a multiple-protein approach. Multivariate statistical methods have been used to describe possible patterns of interaction for lysozyme, lactoferrin, salivary peroxidase and secretory IgA in stimulated parotid saliva. However, oral microbes are most likely to encounter antimicrobial proteins in mixed resting saliva. Relationships among levels of lysozyme, lactoferrin, salivary peroxidase, and secretory IgA therefore were investigated in whole saliva from 216 subjects, and an attempt made to relate interperson variation in those proteins to differences in health and status, and dental plaque accumulation and composition. All proteins were significantly (alpha = 0.05) correlated with each other (r = 0.38-0.52, p less than 0.001). There was only one axis of common variation among proteins, and that axis was significantly correlated (p less than 0.001) with total protein (r = 0.84) and flow rate (r = -0.56). That pattern deviated from the previous finding that proteins of acinar origin tended to vary independently from proteins of ductal origin in stimulated parotid saliva. The difference between parotid and whole saliva may reflect constitutive secretion of all proteins at low levels of stimulation. Common variation of unstimulated saliva proteins suggests that antimicrobial actions can be compared in subjects at population extremes. There were no significant associations between antimicrobial proteins in whole saliva and measures of health status or plaque accumulation. However, the proportions of Streptococcus sanguis were significantly correlated with lysozyme (r = -0.26), lactoferrin (r = -0.34), peroxidase (r = -0.30), total protein (r = -0.37), flow rate (r = 0.24) and principal-components scores (r = -0.33) in a subset of subjects (n = 85) where commercial biochemical tests were used to supplement species identification by colony morphology. Those findings may indicate that saliva antimicrobial proteins can affect the composition of dental plaque.

Temporomandibular joint dysfunction and selected health parameters in the elderly.

Little research has focused on temporomandibular joint dysfunction (TMJD) in the elderly. The present study describes relationships between TMJD and selected health parameters in a population of 75- to 94-year-old Roman Catholic sisters (nuns). Mental, physical, and oral assessments made on 117 sisters identified 26 with TMJD. Among all sisters, TMJD was not associated with age, education, mental impairments, hand coordination, handgrip strength, mobility, or use of walking aids. In 75- to 84-year-old sisters, TMJD was positively associated with self-reported arthritis (p = 0.12), edentulism (p = 0.09), and the presence of complete dentures (p = 0.05), and negatively associated with the number of teeth present (p = 0.05), especially the posterior teeth. These associations were weaker in 85- to 94-year-old sisters. This study suggests that TMJD is associated with the presence of complete dentures and a low number of teeth, especially the posterior teeth.

Phenotypic characterization of Streptococcus sanguis virulence factors associated with bacterial endocarditis.

Certain strains of Streptococcus sanguis adhere (Adh+) selectively to human platelets and, in plasma, induce them to aggregate (Agg+) into in vitro thrombi. In this study, we examined 18 recent endocarditis and dental plaque isolates of microorganisms that were biotyped as S. sanguis for coexpression of platelet interactivity phenotypes with another possible virulence factor in bacterial endocarditis, dextran synthesis. Detectable production of extracellular glucosyltransferase ranged from 0.2 to 66 mU/mg of culture fluid for 10 representative strains tested. Production of extracellular or cell-associated glucosyltransferase, fructosyltransferase, and soluble or insoluble dextrans was not necessarily coexpressed with platelet interactivity phenotypes, since the levels of production of soluble and insoluble dextrans varied among representative Adh+ Agg+ and Adh- Agg- strains. Analysis of a second panel of 38 fresh dental plaque isolates showed that S. sanguis distributes in a reproducible manner into the possible phenotype groups. Strains with different platelet interactivity phenotypes were distinguished with a panel of four murine monoclonal antibodies (MAbs) raised against Adh+ Agg+ strain 133-79 and screened to rule out artifactual reactions with antigenic components in culture media. The MAbs reacted selectively with Adh+ Agg+ strains in a direct-binding, whole-cell, enzyme-linked immunosorbent assay and also inhibited their interactions with platelets. Analysis of minimal tryptic digests of many strains, including variants that failed to bind the MAbs, suggested that some noninteractivity phenotypes possess cryptic surface determinants. Since the ability to adhere to platelets and induce them to aggregate is relatively stable, these traits may be useful in a phenotyping scheme for these Lancefield nontypeable streptococci.

Responses of platelets to strains of streptococcus sanguis: findings in healthy subjects, Bernard-Soulier, Glanzmann's, and collagen-unresponsive patients.

The ability of endocarditis and dental strains of Streptococcus sanguis to induce platelet aggregation in plasma (PRP) from normal subjects were examined and compared to responses of PRP with known platelet membrane glycoprotein (GP) and response defects. S. sanguis strains differed in their ability to induce normal PRPs to aggregate. Strains that induced PRP aggregation in more than 60% of donors were significantly faster agonists (mean lag times to onset of aggregation less than 6 min) than those strains inducing response in PRPs of fewer than 60% of donors. Platelets from patients with Bernard-Soulier syndrome aggregated in response to strains of S. sanguis. In contrast, platelets from patients with Glanzmann's thrombasthenia and from a patient with a specific defect in response to collagen were unresponsive to S. sanguis. These observations show that GPIb and V are not essential, but GPIIb-IIIa and GPIa are important in the platelet response mechanism to S. sanguis. Indeed, the data suggests that the platelet interaction mechanisms of S. sanguis and collagen may be similar.