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PCR for detection and identification of Streptococcus sobrinus
T Igarashi1, A Yamamoto1, N Goto1
1Department of Oral Microbiology, Showa University School of Dentistry, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
Journal of Medical Microbiology
|December 29, 2000
Summary
A new Polymerase Chain Reaction (PCR) method accurately detects Streptococcus sobrinus and Streptococcus mutans, common cariogenic bacteria. This highly specific assay identifies S. sobrinus in 83% of dental plaque samples, revealing a higher prevalence than previously thought.
Area of Science:
- Microbiology
- Molecular Biology
- Dental Research
Background:
- Streptococcus sobrinus and Streptococcus mutans are key cariogenic bacteria.
- Accurate detection methods are crucial for understanding oral microbiome dynamics and developing targeted interventions.
Purpose of the Study:
- To develop and validate a specific Polymerase Chain Reaction (PCR) method for detecting Streptococcus sobrinus.
- To differentiate S. sobrinus from other mutans streptococci using PCR.
Main Methods:
- Oligonucleotide primers were designed based on dextranase (dex) gene sequences.
- PCR was used to amplify a specific DNA fragment from S. sobrinus.
- The specificity of the PCR assay was tested against various oral bacteria, including other mutans streptococci.
- The detection limit of the PCR was determined using purified DNA and bacterial colony-forming units (cfu).
Main Results:
- The developed PCR method specifically amplified DNA from S. sobrinus, yielding a 1610-bp fragment.
- No PCR products were observed for S. mutans or other oral bacteria tested, confirming high specificity.
- The assay could detect as little as 100 fg of S. sobrinus DNA or 9 cfu.
- Application to human dental plaque revealed an 83% prevalence of S. sobrinus, significantly higher than previously reported estimates.
Conclusions:
- The described PCR method is highly specific and sensitive for the detection and identification of Streptococcus sobrinus.
- This assay is suitable for differentiating S. sobrinus from S. mutans and other related species.
- The high prevalence of S. sobrinus found in dental plaque highlights its significant role in oral health and suggests a need for revised epidemiological data.