Purification and characterization of Staphylococcus aureus type 8 capsular polysaccharide

Area of Science:

• Microbiology
• Immunology
• Biochemistry

Background:

• Staphylococcus aureus clinical isolates are classified into eight types based on capsular polysaccharide.
• Type 8 capsular polysaccharide is prevalent in bacteremic isolates, suggesting its role in staphylococcal disease.

Purpose of the Study:

• To purify and characterize the capsular polysaccharide from Staphylococcus aureus type 8.
• To determine the chemical composition and serological distinctiveness of the type 8 capsular polysaccharide.

Main Methods:

• Purification using ion-exchange chromatography and gel filtration.
• Chemical analysis via gas chromatography, gas chromatography-mass spectrometry, and 13C-nuclear magnetic resonance.
• Serological testing using double diffusion assays with type 8 antiserum.

Main Results:

• The type 8 capsular polysaccharide was successfully purified from three clinical isolates.
• Chemical analysis revealed the polysaccharide is composed of O-acetyl groups, N-acetylfucosamine, and an aminouronic acid similar to N-acetylgalactosaminouronic acid.
• The purified polysaccharide reacted specifically with type 8 antiserum, confirming its serological identity.

Conclusions:

• The type 8 capsular polysaccharide of Staphylococcus aureus is chemically unique.
• It is serologically distinct from teichoic acid and other previously characterized S. aureus polysaccharides.
• This distinct antigen may play a significant role in staphylococcal pathogenesis and disease.