Viridans Streptococci
Viridans Streptococci - Related Videos
09:36
Studying Oxidative Stress Caused by the Mitis Group Streptococci in Caenorhabditis elegans
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Cited by 1 •
2019
The nematode Caenorhabditis elegans is an excellent model to dissect host-pathogen interactions. Described here is a protocol to infect the worm with members of the mitis group streptococci and determine activation of the oxidative stress response against H2O2 produced by this group of organisms.
11:09
An Analytical Tool-box for Comprehensive Biochemical, Structural and Transcriptome Evaluation of Oral Biofilms Mediated by Mutans Streptococci
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Cited by 30 •
2011
Biofilms formed on tooth surfaces are highly complex and exposed to constant innate and exogenous environmental challenges, which modulate their architecture, physiology and transcriptome. We developed a toolbox to examine the composition, structural organization and gene expression of oral biofilms, which can be adapted to other areas of biofilm research.
02:14
Preparation of Streptococcus mitis Culture for Host-Pathogen Interaction Studies
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2025
Source: Naji, A., et al. Studying Oxidative Stress Caused by the Mitis Group Streptococci in Caenorhabditis elegans. J. Vis. Exp. (2019).This video demonstrates the method for culturing Streptococcus mitis under microaerophilic conditions using Todd-Hewitt Yeast Extract, or THY agar medium, to prepare bacterial cultures for host-pathogen interaction studies.
11:28
A Reference Broth Microdilution Method for Dalbavancin In Vitro Susceptibility Testing of Bacteria that Grow Aerobically
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Cited by 33 •
2015
Here, we present a protocol for determination of dalbavancin susceptibility of clinically relevant Gram-positive bacteria using a broth microdilution reference methodology.
09:12
An Introduction to the Laboratory Mouse: Mus musculus
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2023
Mice (Mus musculus) are an important research tool for modeling human disease progression and development in the lab. Despite differences in their size and appearance, mice share a distinct genetic similarity to humans, and their ability to reproduce and mature quickly make them efficient and economical candidate mammals for scientific study. This video provides a brief overview of mice, both as organisms and in terms of their many advantages as experimental models. The discussion features an...
FAQs
Extracellular glucans produced by Streptococcus mutans promote attachment to tooth surfaces. This adhesive matrix helps oral bacteria remain associated with enamel rather than being removed. In clinical context, this species-specific property links colonization behavior to dental disease and distinguishes it functionally from other viridans streptococci.
The transition from colonization to disease depends partly on host conditions and species-specific adhesion. Some viridans streptococci can attach to platelet-fibrin deposits on damaged cardiac valves, creating a site where infection may develop. This mechanism helps explain their association with infective endocarditis in susceptible patients.
Damaged cardiac valves and immunocompromised states increase concern because they reduce the barrier between colonization and invasive disease. In these settings, organisms that normally inhabit the oral cavity or gastrointestinal tract may act as opportunistic pathogens. Clinical interpretation therefore depends on both the isolate and the patient’s underlying condition.
Characterization begins with colony morphology and hemolysis, including the commonly observed alpha-hemolytic pattern. Because these findings alone do not establish the species, laboratories also assess catalase, optochin susceptibility, bile solubility, and biochemical or molecular features. Combining results supports more reliable identification and helps guide subsequent clinical decisions.
Optochin susceptibility and bile solubility are components of the laboratory panel used to characterize isolates showing relevant streptococcal features. They should be interpreted with colony morphology, hemolysis, catalase testing, and biochemical or molecular results rather than treated as isolated proof of identity. The combined profile improves diagnostic classification.
Species-level characterization matters because viridans streptococci do not share identical clinical behavior. Streptococcus mutans is associated with glucan-mediated tooth adhesion, whereas other members can adhere to platelet-fibrin deposits and contribute to endocarditis. More precise identification therefore connects laboratory findings with the likely clinical significance of the isolate.
Laboratory characterization supports diagnosis and targeted antimicrobial therapy by combining observable traits with biochemical or molecular testing. This approach helps distinguish clinically meaningful species-specific behavior within a diverse group. In a patient with a susceptible site or immune compromise, the resulting identification can provide a stronger basis for interpreting infection and selecting therapy.