Cariogenic properties of Streptococcus mutans clinical isolates with sortase defects

Area of Science:

• Microbiology
• Oral Health
• Bacteriology

Background:

• Streptococcus mutans is a primary pathogen responsible for dental caries.
• Surface proteins in S. mutans are crucial for virulence and are anchored by sortase enzymes.
• Previous studies focused on laboratory strains, leaving clinical isolates with sortase defects under-investigated.

Purpose of the Study:

• To investigate the cariogenic properties of clinical isolates of Streptococcus mutans with sortase defects.
• To assess the caries status in human subjects harboring these defective S. mutans isolates.

Main Methods:

• Evaluation of sortase-defective clinical isolates for biofilm formation, sucrose-dependent adhesion, and stress-induced aggregation.
• Assessment of acid production and acid tolerance in vitro.
• Determination of caries indices (deft/DMFT) in subjects carrying the defective isolates.

Main Results:

• Sortase-defective isolates formed less biofilm and exhibited impaired sucrose-dependent adhesion and stress-induced aggregation.
• No significant alterations in acid production or tolerance were observed.
• Glucan-binding protein C was detected in the supernatant of sortase-defective isolates, suggesting impaired surface anchoring.
• Despite reduced in vitro cariogenic potential, subjects harboring these isolates showed existing caries experience.

Conclusions:

• Sortase defects impair cariogenic properties of S. mutans clinical isolates.
• The presence of sortase-defective S. mutans does not necessarily correlate with a reduced risk of dental caries in colonized individuals.