[MGB probes detect Streptococcus mutans and Streptococcus sobrinus in real time]

Area of Science:

• Microbiology
• Molecular Biology
• Dental Public Health

Background:

• Streptococcus mutans (S. mutans) and Streptococcus sobrinus (S. sobrinus) are key etiological agents of dental caries.
• Rapid and accurate detection methods are crucial for epidemiological studies and clinical diagnostics.
• Understanding the distribution of these bacteria in children with rampant caries is important for targeted interventions.

Purpose of the Study:

• To develop and evaluate a real-time polymerase chain reaction (PCR) assay using minor groove binder (MGB) probes for the rapid detection and differentiation of S. mutans and S. sobrinus.
• To investigate the prevalence of S. mutans and S. sobrinus in the oral microbiota of preschool children suffering from rampant caries.

Main Methods:

• Minor groove binder (MGB) probes were designed targeting the gtf gene specific to S. mutans and S. sobrinus.
• Real-time PCR assays were performed on reference strains and dental plaque samples from 92 children with rampant caries.
• The performance of the MGB probe assay was evaluated against conventional methods.

Main Results:

• The MGB probes specifically amplified target sequences, enabling accurate differentiation between S. mutans and S. sobrinus.
• Real-time detection showed distinct fluorescence patterns, although results aligned with cultivation methods.
• S. mutans was detected in 96.7% of children, while S. sobrinus was found in 32.6%. All S. sobrinus-positive samples also contained S. mutans.

Conclusions:

• The developed real-time PCR assay utilizing MGB probes is effective for rapid and simultaneous detection and differentiation of S. mutans and S. sobrinus.
• The high prevalence of S. mutans in children with rampant caries underscores its significant role in early childhood caries.
• This molecular tool offers a valuable approach for epidemiological surveillance and diagnosis of cariogenic streptococci.