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Differences in cariogenicity between fresh isolates of Streptococcus sobrinus and Streptococcus mutans
J J de Soet1, C van Loveren, A J Lammens
1Department of Oral Microbiology, Academic Center of Dentistry Amsterdam, The Netherlands.
Caries Research
|January 1, 1991
Summary
Freshly isolated Streptococcus sobrinus strains demonstrated higher cariogenic potential in rats compared to Streptococcus mutans. This suggests differences in glycolytic activity may contribute to the increased acid production and tooth decay caused by S. sobrinus.
Area of Science:
- Microbiology
- Dental Research
- Oral Health
Background:
- Streptococcus sobrinus is recognized for its in vitro cariogenic properties, including significant acid production and adherence to enamel.
- Previous cariogenicity studies often utilized long-term laboratory strains, potentially not reflecting the behavior of fresh bacterial isolates.
- Understanding the virulence of fresh isolates is crucial for accurate assessment of dental caries risk.
Purpose of the Study:
- To compare the cariogenicity and acidogenicity of fresh isolates of Streptococcus sobrinus and Streptococcus mutans.
- To evaluate the colonization efficiency and impact on dental caries in a rat model using fresh bacterial strains.
Main Methods:
- Nine fresh isolates each of S. sobrinus and S. mutans from human dental plaque were inoculated into rats.
- Rats were maintained on a diet high in sucrose and glucose (SSP 20/5) for 42 days.
- Caries assessment, bacterial colonization counts (using monoclonal antibodies), and in vitro acid production (pH-stat system) were performed.
Main Results:
- Four S. sobrinus and three S. mutans strains failed to colonize the rats.
- Colonizing strains represented a significant portion (39-78%) of the cultivable microflora.
- S. sobrinus colonization resulted in significantly more advanced dentinal lesions than S. mutans (p < 0.05).
- In vitro, S. sobrinus exhibited more rapid acid production between pH 6.5 and 5.0 compared to S. mutans (p < 0.01).
Conclusions:
- Freshly isolated strains of Streptococcus sobrinus exhibit greater cariogenic potential in vivo in rats than fresh isolates of Streptococcus mutans.
- The enhanced cariogenicity of S. sobrinus may be attributed to its superior glycolytic properties, leading to faster acid production.
- These findings highlight the importance of studying fresh clinical isolates to accurately assess the virulence of oral bacteria.