Related Experiment Video
Updated: Jul 26, 2026
09:36
Studying Oxidative Stress Caused by the Mitis Group Streptococci in Caenorhabditis elegans
Published on: March 23, 2019
Inhibitory activity of Streptococcus mitis against oral bacteria
Microbios
|January 1, 1979
Summary
Three Streptococcus mitis strains exhibit potent antagonistic properties against diverse oral bacteria. These bacteria produce hydrogen peroxide and an unisolated factor, contributing to their broad inhibitory activity in the oral microbiome.
Area of Science:
- Oral microbiology
- Bacteriology
- Antimicrobial research
Background:
- Oral microbiome composition is crucial for dental health.
- Understanding bacterial interactions can reveal novel therapeutic targets.
- Streptococcus mitis is a common oral commensal with potential antagonistic roles.
Purpose of the Study:
- To investigate the antagonistic properties of Streptococcus mitis strains.
- To identify the mechanisms behind the observed inhibition of oral bacteria.
- To characterize the inhibitory factors produced by S. mitis.
Main Methods:
- Culturing and isolation of three Streptococcus mitis strains.
- Testing inhibitory activity against a panel of Gram-positive and Gram-negative oral bacteria (facultative and anaerobic).
- Assessing the role of hydrogen peroxide in aerobic inhibition.
- Limited characterization of a second, unisolated inhibitory factor using plate cultures.
Main Results:
- Streptococcus mitis strains demonstrated significant inhibition against a wide spectrum of oral bacteria.
- Hydrogen peroxide production was confirmed and partially responsible for aerobic inhibitory activity.
- A second, distinct inhibitory factor was produced both aerobically and anaerobically but remained unisolated.
Conclusions:
- Streptococcus mitis possesses significant antagonistic capabilities against various oral bacteria.
- The observed inhibition is mediated by hydrogen peroxide and at least one other uncharacterized factor.
- These findings highlight S. mitis as a potential source for novel antimicrobial agents in oral care.
More Related Videos
Related Concept Videos
01:18Surface Membrane Barriers
The skin and mucous membranes serve as the primary line of defense against pathogens by providing both physical and chemical protection. These barriers are essential in preventing the entry and establishment of microbes, thereby maintaining the integrity of the host.
The outer layer of the skin, the epidermis, is a robust barrier comprising layers of closely packed keratinized cells. This dense arrangement prevents microbes from penetrating the body. The periodic shedding of epidermal cells...
The outer layer of the skin, the epidermis, is a robust barrier comprising layers of closely packed keratinized cells. This dense arrangement prevents microbes from penetrating the body. The periodic shedding of epidermal cells...
01:27The Oral Microbiota
The oral microbiome includes a complex ecosystem comprising over 700 microbial species, identified through genomic sequencing and culture-based analyses to date. This community includes a core microbiome, found universally among individuals, and a variable component influenced by environmental factors such as diet, lifestyle, and host genetics. Site-specific conditions, including oxygen gradients, pH levels, and nutrient availability, determine the spatial distribution of these microorganisms...
01:28Development of the Oral Microbiota
The establishment of the oral microbiome begins before birth, challenging the long-held belief that the fetal oral cavity is sterile. The presence of oral microbes such as Streptococcus and Fusobacterium in amniotic fluid suggests that microbial exposure may occur in utero, potentially through translocation from the maternal oral or gastrointestinal tract. This early colonization primes the neonatal immune system and sets the stage for subsequent microbial succession. Maternal health,...
01:29Microbiota of the Respiratory Tract
The human respiratory tract, comprising the upper and lower segments, serves as a critical interface with the external environment. The upper respiratory tract (URT)—including the nostrils, sinuses, pharynx, and oropharynx—is heavily colonized by microbes, while the lower respiratory tract (LRT), composed of the larynx, trachea, bronchi, and lungs, was long thought to be sterile. However, recent molecular studies have revealed that the lungs are not devoid of microbes but act more like...
01:25Inhibitors of Bacterial Protein Synthesis
Aminoglycosides constitute a highly potent class of bactericidal antibiotics that exert their antimicrobial effects by targeting the bacterial ribosome, specifically disrupting protein synthesis. These polycationic molecules consist of amino-modified sugars linked via glycosidic bonds to an aminocyclitol core such as 2-deoxystreptamine or streptamine. Their strong positive charges facilitate tight binding to the negatively charged phosphate backbone of ribosomal RNA (rRNA), primarily at the 16S...
01:25Clinical Significance of Antibiotic Resistance
Methicillin-resistant Staphylococcus aureus (MRSA) presents a critical public health threat, arising from its capacity to resist β-lactam antibiotics due to acquisition of the mecA gene within the staphylococcal cassette chromosome mec (SCCmec). This gene encodes penicillin-binding protein 2a (PBP2a), which impairs binding efficacy of methicillin and other β-lactams. MRSA has evolved into distinct clonal lineages impacting humans and animals alike, reinforcing its significance within the One...