[Changes in surface characteristics of group A streptococci].

Area of Science:

• Microbiology
• Bacterial Pathogenesis
• Streptococcal Infections

Background:

• Group A Streptococcus (GAS) is a significant human pathogen.
• Bacterial surface characteristics, including hydrophobicity, influence host-pathogen interactions.
• M protein is a key virulence factor in GAS, affecting surface properties.

Purpose of the Study:

• To investigate the surface hydrophobicity of GAS strains.
• To correlate surface characteristics with M protein production and growth phase.
• To assess the impact of sub-inhibitory antibiotic concentrations on GAS surface properties.

Main Methods:

• Utilized salt aggregation technique to assess surface hydrophobicity.
• Employed adhesion to n-hexadecane assay to evaluate surface properties.
• Examined four GAS strains in both log and stationary growth phases.
• Pretreated bacteria with sub-minimum inhibitory concentrations (sub-CMI) of clindamycin and imipenem.

Main Results:

• A strong correlation between surface hydrophobicity and M protein production was observed, particularly in the stationary growth phase.
• Adhesion to n-hexadecane revealed growth-phase-dependent differences unrelated to M protein.
• Clindamycin treatment significantly decreased hydrophobicity in M+ strains and during stationary phase.
• M- strains and imipenem treatment showed minimal changes in surface properties.

Conclusions:

• Bacterial surface hydrophobicity in GAS is linked to M protein expression and growth phase.
• Antibiotic pretreatment, specifically with clindamycin, can modulate GAS surface characteristics.
• These findings provide insights into GAS virulence mechanisms and potential therapeutic targets.