Many of the protective immune responses of old people are impaired and this leads to an increased risk of oral bacterial infections. Little is known about the interaction between the systemic immune response on one hand and oral infections and oral diseases on the other. Here, we conducted an epidemiological study of the independent elderly to determine the relationships between activated natur...

A more sensitive test agar was developed to detect oral microbes with relatively low dextranase activity and to identify dextranase-negative mutants. Several oral streptococci that had previously been scored as dextranase negative readily decolorized the new, blue dextran-containing medium. To assess whether dextranase plays a role in glucan synthesis by oral streptococci, various glucan synthe...

INTRODUCTION Streptococcus mutans and Streptococcus sobrinus are the main causative organisms for enamel demineralization during orthodontic treatment. In this study, we analyzed the prevalence of cariogenic streptococci adhering to incisor brackets. METHODS Four incisor brackets from both the maxilla and the mandible were collected from 80 patients at debonding, immediately after the visible...

Bacteriophage lytic enzymes quickly destroy the cell wall of the host bacterium to release progeny phage. Because such lytic enzymes specifically kill the species in which they were produced, they may represent an effective way to control pathogenic bacteria without disturbing normal microflora. In this report, we studied a murein hydrolase from the streptococcal bacteriophage C(1) termed lysin...

background/purpose: although habitual consumption of xylitol reduces cariogenic streptococci levels, its effect on beneficial oral streptococci is less clear. the main aim of the study is to investigate the effect of short-term xylitol consumption on the oral beneficial streptococci level of saliva, streptococcus sanguinis and s. mitis . material and methods: twenty four volunteers with a media...

Dental caries-associated oral streptococci are called the mutans streptococci, with Streptococcus mutans and Streptococcus sobrinus being the most prevalent caries-associated organisms in humans. Strains of the mutans streptococci are highly conserved within not only mothers and their children but also racial groups, suggesting vertical transmission of this organism within human populations. It...

Endocarditis is frequently attributable to oral streptococci, but mechanisms of pathogenesis are not well understood, although monocytes appear to be important. High titers of interleukin-12 (IL-12) are produced by peripheral blood mononuclear cells (PBMC) after engaging Streptococcus mutans, but monocytes in developing endocardial vegetations tend to disappear rather than become macrophages. T...

To persist in the oral cavity, bacteria must be able to tolerate rapid and substantial environmental fluctuations, particularly in pH and nutrient source and availability. Various species of Streptococcus, one of the most abundant genera in the mouth, are associated with oral health, as well as with dental caries. Cariogenic streptococci depend on a biofilm lifestyle for survival and persistenc...