Agglutination of Staphylococcus aureus by rabbit sera

Area of Science:

• Microbiology
• Immunology
• Bacteriology

Background:

• Staphylococcus aureus serotyping is essential for epidemiological studies.
• Traditional methods may be limited in specificity and sensitivity.
• The role of specific bacterial components in agglutination reactions requires further elucidation.

Purpose of the Study:

• To investigate the mechanism of Staphylococcus aureus agglutination in normal rabbit serum.
• To determine the role of protein A and immunoglobulin G (IgG) in this agglutination.
• To evaluate alternative methods for Staphylococcus aureus serotyping.

Main Methods:

• Testing 137 Staphylococcus aureus strains for agglutination in normal rabbit serum.
• Utilizing F(ab(1))(2)-fragments of IgG and immunoglobulin M (IgM) to identify reactive components.
• Correlating agglutination patterns with protein A content in the strains.

Main Results:

• 87 out of 137 Staphylococcus aureus strains showed agglutination.
• Agglutination was attributed to the Fc-part of immunoglobulin G (IgG).
• High or moderate protein A content correlated with agglutination; low or absent protein A did not.

Conclusions:

• The interaction between the Fc part of IgG and protein A is a key factor in Staphylococcus aureus agglutination.
• This Fc-IgG/protein A interaction is important for Staphylococcus aureus serotyping.
• Alternative serotyping methods using F(ab(1))(2) fragments of IgG or intact IgM are proposed.